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  • Coleoptera
  • Wheat
  • paleolimnology
  • stress
  • Springer  (788)
  • 1995-1999  (452)
  • 1980-1984  (336)
  • 1925-1929
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  • 1
    Electronic Resource
    Electronic Resource
    The impact of the egg parasitoid Uscana lariophaga on Callosobruchus maculatus populations and the damage to cowpea in a traditional storage system (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 289-295 
    Details
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Trichogrammatidae ; Uscana lariophaga ; Coleoptera ; Bruchidae ; Callosobruchus maculatus ; cowpea ; storage pest ; biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In West Africa, Uscana lariophaga (Hymenoptera: Trichogrammatidae) parasitizes the eggs of Callosobruchus maculatus (Coleoptera: Bruchidae), an important pest of stored cowpea. The impact of the egg parasitoid on pest populations was evaluated in clay pots used in traditional storage in Niger. At the beginning of the storage period cowpeas were infested with different densities of larval instars and adults of C. maculatus and inoculated with one density of U. lariophaga. The higher the initial densities of C. maculatus, the better the egg parasitoid was able to establish itself and to control the population of C. maculatus, limiting the damage to cowpea. After three months of storage, the egg parasitoid significantly reduced the number of C. maculatus adults by 68 at the lowest and 86 percent at the highest initial density of the beetle; the percentage of damaged beans was reduced by 13 and 19% respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003555413273
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of leaf pubescence in Salix borealis on host- plant choice and feeding behaviour of the leaf beetle, Melasoma lapponica (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 297-303 
    Details
    ISSN: 1570-7458
    Keywords: leaf pubescence ; host-plant preference ; consumption rate ; feeding behaviour ; delayed induced resistance ; Coleoptera ; Chrysomelidae ; Kola Peninsula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Density of leaf trichomes in Salix borealis affected both the choice of individual host plants and feeding behaviour of adults and last instar larvae of the willow feeding leaf beetle, Melasoma lapponica. Beetles clearly preferred shaved disks to unshaved ones taken from the same leaf; this preference was highest in leaves of the most pubescent plants. High leaf pubescence explained the low preference for willow clones from the high density site in among-site preference trials; shaving significantly increased the consumption of these pubescent willow clones. In no-choice experiments, the food consumption by both adults and last instar larvae decreased with an increase in leaf pubescence. The time budget of adults did not depend on leaf pubescence of the host plants, however adults compelled to feed on highly pubescent plants changed their feeding sites twice as often as on less pubescent willow clones. Larvae feeding on highly pubescent plants spend moving three times as much time as larvae feeding on less pubescent plants. Combined with our earlier observations on the increase in leaf pubescence in the year(s) following defoliation, these data suggest that leaf hairiness may have contributed to the delayed induced resistance in S. borealis by disturbing the feeding behaviour of M. lapponica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003591204999
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  • 3
    Electronic Resource
    Electronic Resource
    Field trapping of Metamasius hemipterus with synthetic aggregation pheromone (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 453-460 
    Details
    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Metamasius hemipterus ; aggregation pheromone ; redundancy ; field trapping ; sex-ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The five synthetic pheromone components of the West Indian sugarcane borer (WISB), Metamasius hemipterus (L.) (Coleoptera, Curculionidae) were tested in the field. The combination of sugarcane (SC) and the major pheromone compound, 4-methyl-5-nonanol (1) was attractive. However, the addition of 2-methyl-4-heptanol (2) or 2-methyl-4-octanol (3) was required to reach high catch levels while 5-nonanol (4) or 3-hydroxy-4-methyl-5-nonanone (5) did not enhance WISB attraction. The redundancy phenomenon, here reported for the first time in rhynchophorinous species, was observed between compounds 2 and 3. SC +1 +3 was more attractive than living male baits, however, the sex-ratio of the catches was equivalent between both treatments. The sex-ratio of catches was affected by the qualitative composition of the pheromone formulation. Compound 3 had a sexual role, attracting more females while 5 seemed to play an aggregation role, luring both sexes in the same proportion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343468
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of selected physical and chemical treatments of Colorado potato beetle eggs on host acceptance and development of the parasitic wasp, Edovum puttleri (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 237-245 
    Details
    ISSN: 1570-7458
    Keywords: physical and chemical effects ; parasitization ; Colorado potato beetle ; Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae ; Edovum puttleri ; Hymenoptera ; Eulophidae ; UV irradiation ; host age ; freezing ; kairomone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of various physical and chemical treatments of Colorado potato beetle [Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)] eggs on parasitization and development of the egg parasitoid Edovum puttleri (Hymenoptera: Eulophidae) were investigated. UV irradiation did not affect host acceptance but reduced host suitability for UV exposure times ≥90 min. Susceptibility of host eggs to UV irradiation varied with host age; eggs were most vulnerable to damage from irradiation at 12, 18, and 24 h post-oviposition. The rate of parasitization also was influenced by host age. Percent parasitization was greatest in freshly laid eggs and 24–30 h old eggs. Seventy-seven percent of host eggs frozen at −20 °C (5 min) were parasitized by E. puttleri, but extended exposure of eggs to −20 °C reduced both acceptance and suitability. Host eggs that had been washed with hexane (removal of kairomone and sticky layer) also were parasitized. After 5 min of washing, application of kairomone significantly increased the rate of parasitism (from 74.7% to 88.2%), but with longer periods of washing, kairomone application had no significant effect on percent parasitism. Thus, the sticky material(s) coating the egg did not appear to be essential for parasitization to occur. Our results provide effective methods and times for treating Colorado potato beetle eggs to maximize parasitization and development of E. puttleri.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026425813762
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  • 5
    Electronic Resource
    Electronic Resource
    Factors influencing dispersal of larval Coleomegilla maculata from the weed Acalypha ostryaefolia to sweet corn (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 313-322 
    Details
    ISSN: 1570-7458
    Keywords: Coleoptera ; Coccinellidae ; Coleomegilla maculata ; Euphorbiaceae ; Acalypha ostryaefolia ; Zea mays ; dispersal ; predator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The polyphagous predator, Coleomegilla maculata (DeGeer) (Coleoptera: Coccinellidae), commonly oviposits on the native weed, Acalypha ostryaefolia Riddell (Euphorbiaceae), in and around Kentucky sweet corn fields. Cannibalism of eggs by C. maculata adults and larvae is drastically lower on A. ostryaefolia than on nearby sweet corn plants. We examined ovipositional preference of C. maculata for A. ostryaefolia plants or sweet corn plants, dispersal of larvae from A. ostryaefolia plants, capability for dispersal of larvae across bare soil (e.g., to nearby plants), ability of larvae to climb from ground level up A. ostryaefolia plants or sweet corn plants, and effect of A. ostryaefolia borders adjacent to sweet corn plots on C. maculata population density in sweet corn. The ovipositional preference study revealed that C. maculata laid more eggs on A. ostryaefolia than on corn. First-instar C. maculata that hatched from egg clusters on A. ostryaefolia dispersed predominantly by falling, rather than crawling, to the ground. Glandular trichomes on A. ostryaefolia petioles and stems apparently inhibited intraplant movement of first instars, resulting in those larvae falling directly from leaves to the ground. Some first instars were capable of moving at least 8 m across bare soil in 24 h. From the ground, significantly more first instars climbed sweet corn plants than climbed A. ostryaefolia plants. Significantly more larvae were present in sweet corn plots bordered by A. ostryaefolia plants than in sweet corn plots without an A. ostryaefolia border. These findings show that physical attributes of companion plants can significantly influence natural enemy populations on crop plants by affecting interplant dispersal of natural enemies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026429217088
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of lectins, CRY1A/CRY1B Bt α-endotoxin, PAPA, protease and ;4-amylase inhibitors, on the development of the rice weevil, Sitophilus oryzae, using an artificial seed bioassay (1997)
    Springer
    Entomologia experimentalis et applicata 82 (1997), S. 201-211 
    Details
    ISSN: 1570-7458
    Keywords: biomonitor ; Coleoptera ; Curculionidae ; lectin ; PAPA ; E-64 ; artificial seeds ; protease inhibitor ; weevil ; Sitophilus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An artificial maize seed bioassay was developed to evaluate potential resistance factors against the rice weevil, Sitophilus oryzae. Weevils reared in artificial seeds compared to those reared in whole maize seeds: (i) developed faster, (ii) had similar within-seed developmental mortalities, (iii) were lighter in weight upon emergence and (iv) oviposited the same number of eggs. Using this bioassay we found that E-64, a cysteine protease inhibitor, decreased the number of emerged adults per seed and delayed within-seed developmental time, suggesting that the rice weevil utilizes a cysteine protease to digest its dietary protein. Weevils fed inhibitors of trypsin and chymotrypsin, Bowman-Birk and Kunitz inhibitors respectively, developed normally. Para-amino-l-phenylalanine (PAPA), a non-protein amino acid implicated as an insect resistance factor in Vigna vexillata, was lethal at dietary levels of 0.2% (w/w) and higher. An extract from Amaranthus caudatus seeds delayed the developmental time of the rice weevil at dietary levels of 0.2% (w/w) and increased mortality at dietary levels of 1.0% (w/w). Several proteins tested, including Griffonia simplicifolia agglutinin II, phytohemagglutinin extract containing common bean α-amylase inhibitor, pokeweed agglutinin, Bacillus thuringiensis CRY1A/CRY1B endotoxin, and an α-amylase inhibitor from wheat, had no effect on the rice weevil. The artificial maize seed bioassay was adapted by pelleting the seed for use with an ultrasonic insect feeding monitor to determine the finding activity of rice weevils as they developed from egg hatch to pupation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1002925301696
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  • 7
    Electronic Resource
    Electronic Resource
    Reproductive status and flight activity of the overwintered Colorado potato beetle (1999)
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 443-448 
    Details
    ISSN: 1570-7458
    Keywords: Colorado potato beetle ; Coleoptera ; Chrysomelidae ; mating ; flight ; insecticide resistance management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mating behavior of post-diapause Colorado potato beetles, Leptinotarsa decemlineata (Say), was observed within an overwintering site, a rotated potato field, newly colonized potato plants, and under laboratory conditions. The influence of spring mating on beetle flight in the presence and in the absence of host plants was investigated using a computer-linked flight mill system. Diapause was terminated simultaneously in male and female beetles, and the first matings were observed as early as within the first 24 h after the beetles emerged from the soil (60–90 DD accumulated). The beetles mated within the overwintering site, the potato field, and the fields rotated out of potatoes. Mating status did not affect flight behavior of overwintered beetles; however, unfed beetles displayed higher flight activity than fed beetles. Most flight activity took place soon after flight muscle regeneration, and then declined sharply by the 5th day after flight initiation. Mating in or near overwintering sites soon after diapause termination might be an important factor in providing gene flow between insecticide-resistant and insecticide-susceptible Colorado potato beetle populations, and should be considered in designing resistance management plans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003603107890
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  • 8
    Electronic Resource
    Electronic Resource
    Flight initiation byProstephanus truncatus in relation to time of day, temperature, relative humidity and starvation (1995)
    Springer
    Entomologia experimentalis et applicata 75 (1995), S. 273-277 
    Details
    ISSN: 1570-7458
    Keywords: Prostephanus truncatus ; larger grain borer ; Coleoptera ; Bostrichidae ; flight initiation ; take-off ; wingopening ; stored products insect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies were carried out in the laboratory on the influences of time of day, temperature, relative humidity and starvation on flight initiation byProstephanus truncatus (Horn) (Coleoptera: Bostrichidae). Flight occurred throughout the 12 h photophase and at the beginning of the scotophase but peaked at 2–0 h before darkness. Temperature exerted a significant effect on flight. The frequency of flight take-off increased with temperature over the range 20–30°C but declined sharply at 35°C. Flight activity increased with starvation up to a maximum at 2 days after which it began to decline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02382263
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  • 9
    Electronic Resource
    Electronic Resource
    Allozyme variation among Brazilian and U.S. populations of Rhyzopertha dominica resistant to insecticides (1997)
    Springer
    Entomologia experimentalis et applicata 84 (1997), S. 49-57 
    Details
    ISSN: 1570-7458
    Keywords: allozymes ; genetic variation ; Rhyzopertha dominica ; Brazil ; USA ; insecticide resistance ; Coleoptera ; Bostrichidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The lesser grain borer (Rhyzopertha dominica (F.)) is an important pest of stored grain in many parts of the world (Paleartic, Ethiopian, Oriental, Australian, Neotropical, and Neartic regions) with the ability to fly long distances. These insects have been shown to be resistant to organophosphorus insecticides in several studies. Polyacrylamide gel electrophoresis was used to assess the genetic variability within and among eight Brazilian and seven United States populations of R. dominica and to determine how insecticide resistance may be spreading within both countries. Significant variation in allele frequency among populations was observed at all six polymorphic enzyme loci that were examined. The Brazilian and U.S. populations were genetically differentiated from one another; populations within the U.S. and those within Brazil were also differentiated from one another. The mean genetic similarity among the seven U.S. populations collected in a small region in northeast Kansas was smaller than that among eight Brazilian populations collected in a relatively large geographical area. These results are consistent with the resistance ratios to chlorpyriphos-methyl in R. dominica populations from Brazil and the U.S. and the information available concerning patterns of flight activity in this insect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003018305244
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  • 10
    Electronic Resource
    Electronic Resource
    Selection of fruits for oviposition by the chestnut weevil, Curculio elephas (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 71-78 
    Details
    ISSN: 1570-7458
    Keywords: chestnut weevil ; Coleoptera ; Curculionidae ; selection of fruits ; host-markers ; larval noise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Under field conditions, females of the chestnut weevil Curculio elephas select their oviposition sites. In sleeve experiments, when the number of fruits is limited, females avoid 17% of available chestnuts and concentrate their eggs in the others. In the field, on average, 56.3 and 27.8% of the infested fruits contain one or two immatures (eggs and larvae). The oviposition site selection is neither influenced by host size nor by the presence of immature conspecifics. Choice experiments in the laboratory suggest that female weevils do not deposit repellent chemical markers on the fruits. Moreover, sleeve experiments indicate that selection is not influenced by the noise made by larvae while feeding inside a fruit. In general, the most probable hypothesis is that Curculio elephas exploits only hosts of highest feeding quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003178026887
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  • 11
    Electronic Resource
    Electronic Resource
    Genetic differentiation of groundnut seed-beetle populations in Senegal (1998)
    Springer
    Entomologia experimentalis et applicata 87 (1998), S. 171-180 
    Details
    ISSN: 1570-7458
    Keywords: Caryedon serratus ; Coleoptera ; Bruchidae ; genetic differentiation ; biotypes ; Senegal ; groundnut ; Caesalpinioideae ; Leguminosae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Caryedon serratus, the groundnut seed-beetle, is a major pest of groundnut (Arachis hypogaea), an introduced legume in the subfamily Papilionoideae. Native hosts of C. serratus in Senegal include Bauhinia rufescens, Cassia sieberiana, Piliostigma reticulatum and Tamarindus indica, all of which belong to the legume subfamily Caesalpinioideae. The biology and natural history of C. serratus suggest that it is a candidate for population differentiation via host-race formation. Evidence for host-tree associated differentiation in C. serratus would be important for the design of rational pest management practices. To test this possibility, we analyzed the genetic structure of 20 adult collections of C. serratus from six sites in Western Senegal, on its five hosts. Results show a strong differentiation of insects from different host trees, with specimens from C. sieberiana possibly representing a sibling species and insects from B. rufescens a distinct host-race.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003268331207
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  • 12
    Electronic Resource
    Electronic Resource
    Mortality in Oryzaephilus surinamensis following short-term exposure to conditioned kernels by high-density culture (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 555-557 
    Details
    ISSN: 1570-7458
    Keywords: Oryzaephilus surinamensis ; Coleoptera ; Cucijidae ; population density ; semiochemicals ; lethal secretions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343481
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  • 13
    Electronic Resource
    Electronic Resource
    Effects of fumonisin B1 on growth and metabolism of larvae of the yellow mealworm, Tenebrio molitor (1998)
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 135-143 
    Details
    ISSN: 1570-7458
    Keywords: yellow mealworm ; contaminated diet ; fungi ; Fusarium moniliforme ; mycotoxins ; feeding bioassay ; toxicity ; nutritional indices ; Coleoptera ; Tenebrionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The chronic and acute toxicity of fumonisin B1 (FB1), a mycotoxin from Fusarium moniliforme, to the larvae of the yellow mealworm, Tenebrio molitor, was assessed. The toxin was administered via the diet or injected directly into the larvae. Young T. molitor larvae fed on a diet containing 450 µg FB1 per g diet exhibited reduced growth performance but only after consuming the fumonisin-contaminated diet for several weeks. FB1-contaminated diet also reduced the rate of carbon dioxide production, food consumption and protein metabolism. The concentrations of FB1 in the diet did not increase mortality, even when tested at the highest dose of 450 µg FB1 per g of diet. Injection of 25 ng FB1 per larva decreased the CO2 production, but became significant only 11 days after the injection and was reversible with time. A parallel analysis of the retention of FB1 by the larvae indicated that about 40% of the ingested FB1 was excreted in the faeces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003141712796
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  • 14
    Electronic Resource
    Electronic Resource
    Fecundity and juvenile survival of shape Bembidion lampros and Tachyporus hypnorum (1998)
    Springer
    Entomologia experimentalis et applicata 87 (1998), S. 301-309 
    Details
    ISSN: 1570-7458
    Keywords: Age-dependent fecundity ; Coleoptera ; Carabidae ; Staphylinidae ; life history traits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fecundity and development from first instar larvae to adult beetles were studied for Bembidion lampros Herbst (Coleoptera; Carabidae) and Tachyporus hypnorum F. (Coleoptera; Staphylinidae). Both species reproduce in arable fields, where they are known to contribute to the natural control of cereal aphids. They are univoltine and have similar life cycles and development times. T. hypnorum females laid approximately 3 times more eggs than B. lampros females. Relative lifetime fecundity of B. lampros was very low with an average of 10 eggs per female. Based on the time where half of the populations had dispersed from the overwintering sites into an arable field B. lampros started egg-lay 100°D (°C〉9) and T. hypnorum 200°D (°C〉3) after dispersal. Mortality in the juvenile stages was found to be an important factor in the population dynamics of both B. lampros and T. hypnorum. The survival from first instar larvae to adults was on average 34% for B. lampros independent of soil type, 21% for T. hypnorum developed in sandy soil and 49% when developed in clayey soil under semi-field conditions. Enlargement of B. lampros and T. hypnorum populations to increase the natural control of aphids during their establishment in cereal fields may be possible if the conditions for juvenile development are improved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003228006214
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  • 15
    Electronic Resource
    Electronic Resource
    Deathwatch beetle, Xestobium rufovillosum, in historical buildings: monitoring the pest and its predators (1999)
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 97-104 
    Details
    ISSN: 1570-7458
    Keywords: deathwatch beetle ; Xestobium rufovillosum ; Coleoptera ; Anobiidae ; timber pest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Trapping and monitoring experiments were conducted in the roof spaces of four buildings infested with deathwatch beetle, Xestobium rufovillosum de Geer (Coleoptera: Anobiidae). Data from sticky traps and an ultra-violet insectocutor showed that adult deathwatch beetles were trapped from May to July. The beetles were attracted to natural and UV light, and more beetles were caught on white coloured traps than yellow, blue or red traps. Deathwatch beetles comprised 30–40% of all arthropods caught. The weekly trap catch of all arthropods, including deathwatch beetle, was positively correlated with ambient temperature. Adult beetles flew in buildings at ambient temperatures greater than 17 °C. Arthropods caught in the buildings were categorised as resident, over-wintering or non-resident arthropods. Predatory spiders comprised 13% of arthropods caught and the predatory beetle, Korynetes caeruleus de Geer, was found in all four buildings. There was no evidence of other predators or parasitoids of the deathwatch beetle
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003824910137
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  • 16
    Electronic Resource
    Electronic Resource
    Avoidance of willows from moderately polluted area by leaf beetle, Melasoma lapponica: effects of emission or induced resistance? (1996)
    Springer
    Entomologia experimentalis et applicata 79 (1996), S. 355-362 
    Details
    ISSN: 1570-7458
    Keywords: aerial pollution ; heavy metals ; sulphur dioxide ; feeding preference ; Salix ; Melasoma lapponica ; Coleoptera ; Chrysomelidae ; population density ; induced resistance ; plant communication ; Kola Peninsula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied preference for willows along a pollution gradient on the Kola Peninsula, Russia, by the leaf beetle, Melasoma lapponica. Multiple tests with leaf disks demonstrated low preference for Salix borealis, S. caprea and S. phylicifolia from the plot situated 14 km from the smelter, in comparison with conspecific plants from plots situated at 1 and 29 km distances. This pattern was observed when testing beetles orginating from any plot both in 1993 and 1994, using both young and mature leaves of S. borealis. Although fumigation of S. borealis with realistic SO2 concentration (100 μg/m3) increased plant palatability, preference for plants from our study plots did not correlate with plot-specific mean SO2 concentrations. Furthermore, no correlation with foliar concentrations of the main metal pollutants (Ni and Cu) was found. Palatability of plants was negatively correlated with population density of M. lapponica, which peaked in the moderately polluted plot 14 km from the smelter. Within this plot, beetles clearly preferred non-damaged bushes of S. borealis to previously damaged bushes. We therefore conclude that low preference of S. borealis from the moderately polluted area was caused by plant resistance induced by severe damage from M. lapponica in previous years rather than by pollution impact. However, S. caprea and S. phylicifolia had little damage from M. lapponica, and low palatability of these species in the moderately polluted plot suggests changes in plant quality similar to changes in heavily damaged bushes of S. borealis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186294
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  • 17
    Electronic Resource
    Electronic Resource
    Intraspecific variability in adult flea beetle behaviour and larval performance on an atypical host plant (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 160-162 
    Details
    ISSN: 1570-7458
    Keywords: Phyllotreta nemorum ; Barbarea vulgaris ; Coleoptera ; Chrysomelidae ; Cruciferae ; resistance ; genetics of insects ; inheritance ; Y-linkage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194748
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  • 18
    Electronic Resource
    Electronic Resource
    Potential impact of Coleomegilla maculata predation on adaptation of Leptinotarsa decemlineata to Bt-transgenic potatoes (1997)
    Springer
    Entomologia experimentalis et applicata 82 (1997), S. 91-100 
    Details
    ISSN: 1570-7458
    Keywords: Bacillus thuringiensis ; Leptinotarsa ; Coleomegilla ; potato ; resistance ; Coleoptera ; Coccinellidae ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between Leptinotarsa decemlineata Say egg density and Coleomegilla maculata DeGeer predatory behavior was investigated at different spatial scales (plant-to-plant and plot-to-plot). Both adult C. maculata location and daily egg consumption rates were monitored over time in greenhouse and field tests. Despite aggregation in areas of highest prey density by C. maculata, egg consumption was inversely related to egg mass density at the smallest and the largest spatial scales tested. The experimental data on predation rates in high and low density field treatments were included in a mathematical model to simulate impact of natural enemies on the rate of L. decemlineata adaptation to Bt-toxin-expressing transgenic potato plants when Bt-expressing plants are mixed at the plot-to-plot level with normal potato plants. Results showed that C. maculata predatory behavior could decrease the rate at which L. decemlineata adapted to Bt-toxins if plot-to-plot mixed-plantings were used.
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    URL: http://dx.doi.org/10.1023/A:1002935706990
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    Cholesterol oxidase: an oöstatic and larvicidal agent active against the cotton boll weevil,Anthonomus grandis (1995)
    Springer
    Entomologia experimentalis et applicata 74 (1995), S. 253-258 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Anthonomus grandis ; cholesterol oxidase ; insecticidal protein ; oöstatic agent ; transgenic cotton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The enzyme cholesterol oxidase (E.C. 1.1.3.6), purified fromStreptomyces culture filtrate was previously found to have oral insecticidal activity on neonate larvae of the boll weevil (Anthonomus grandis grandis Boheman) from a laboratory population. In the present study, second instar larvae were also controlled by the enzyme at diet concentrations similar to those which control neonates (12 day LC50=2.4 μg.ml−1 in diet). Larvae from field-collected adults were similarly susceptible to cholesterol oxidase in the diet. When ingested by adult females during the mating/pre-oviposition period, cholesterol oxidase greatly reduced subsequent oviposition (83% reduction in eggs laid as compared to controls) and larval survival (97% reduction from controls). Dissection of treated adult females revealed poorly developed ovaries and few developing oöcytes. These studies were conducted to further evaluate the utility of cholesterol oxidase in a program to establish boll weevil-resistant transgenic cotton.
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    URL: http://dx.doi.org/10.1007/BF02381789
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    Response of the pollen beetle Meligethes aeneus to volatiles emitted by intact plants and conspecifics (1997)
    Springer
    Entomologia experimentalis et applicata 84 (1997), S. 183-188 
    Details
    ISSN: 1570-7458
    Keywords: Meligethes aeneus ; pollen beetle ; Coleoptera ; Nitidulidae ; Brassica napus ; oilseed-rape ; Y-tube-olfactometer ; host plant location ; epideictic pheromone ; sex determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The response of the pollen beetle Meligethes aeneus Fab. (Coleoptera, Nitidulidae) to the volatiles of undamaged plants and conspecifics was tested in a Y-tube-olfactometer-bioassay. Beetles that had hibernated preferred significantly the volatiles emitted by their most important host plant, oilseed-rape (Brassica napus L. ‘Lorar’) in the early bud-stage. However, the odour emitted by rye (Secale cereale L.), tomato plants (Solanum lycopersicum L.), and yarrow (Achillea millefolium L.) were also attractive when tested against the corresponding growing-medium. Dock plants (Rumex obtusifolius L.) and touch-me-not (Impatiens parviflora L.) possessed no attractive properties. When tested against each other, oilseed-rape was preferred significantly by M. aeneus above all other plants, with the exception of tomato. The results indicate that M. aeneus is able to locate its host plant by olfactory stimuli in the early bud-stage, i.e. in that stage in which the infestation begins in the field and when the typical yellow colour and floral scent of oilseed-rape are absent. Female pollen beetles avoided significantly the volatiles emitted by female conspecifics and an ether extract of conspecifics of mixed sex, while volatiles from males had no significant effect on females. Furthermore, males showed no preferences when responding to conspecific odour in the olfactometer. These results suggest the existence of an epideictic pheromone for M. aeneus.
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    URL: http://dx.doi.org/10.1023/A:1003040318376
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    Development of pheromone traps for control and monitoring of sweetpotato weevils, Cylas puncticollis and C. brunneus, in Uganda (1997)
    Springer
    Entomologia experimentalis et applicata 85 (1997), S. 95-104 
    Details
    ISSN: 1570-7458
    Keywords: Cylas puncticollis ; Cylas brunneus ; sweetpotato weevil ; pheromone ; pheromone trap ; Coleoptera ; Apionidae ; Africa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments were carried out in Uganda to optimise pheromone traps for the African sweetpotato weevil species, Cylas puncticollis Bohe. and C. brunneus F. (Coleoptera: Apionidae). Various designs of funnel, water and sticky traps were compared and a 5-l plastic jerry can trap was the most appropriate design for effectiveness and practicability. A solution of Omo detergent in water was found to be the most effective trapping agent. Fewer weevils were caught in red traps than in yellow, white, green or blue traps. Catches of C. puncticollis increased when the trap was raised above crop height, but catches of C. brunneus were unaffected. When marked weevils were dropped onto the trap, 36% of C. puncticollis and 23% of C. brunneus were captured, and, of weevils placed in the trap, 88% and 92%, respectively, of the two species remained overnight. Lures for the two species showed no significant loss in attractiveness after 8 weeks in the field, and chemical analysis showed 19% of the C. puncticollis pheromone and 72% of the C. brunneus pheromone remaining after this time. Summarizing, the following trap is presently recommended for monitoring/controlling African Cylas species: a 5-l plastic jerry can trap of any colour with rectangular openings of 11×5 and 6×5 cm positioned 15 cm above the crop canopy, filled with 0.5 l Omo solution (1 g/1 l water), with 0.1 mg lures to be replaced every 8 weeks.
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    URL: http://dx.doi.org/10.1023/A:1003031031155
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    Flight behavior of pre- and postdiapause apple blossom weevils in relation to ambient temperature (1998)
    Springer
    Entomologia experimentalis et applicata 88 (1998), S. 97-99 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Anthonomus pomorum ; temperature ; diapause ; flight behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1023/A:1003269621622
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    Can the coffee berry borer (Hypothenemus hampei) reproduce by parthenogenesis? (1995)
    Springer
    Entomologia experimentalis et applicata 77 (1995), S. 351-354 
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    ISSN: 1570-7458
    Keywords: Hypothenemus hampei ; Coleoptera ; Scolytidae ; parthenogenesis ; sexual reproduction ; spanandry ; coffee berry borer ; inbreeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02383071
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    Comparative effect of short term exposures of Callosobruchus subinnotatus to carbon dioxide, nitrogen, or low temperature on behavior and fecundity (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 243-248 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; bruchidae ; anesthesia ; carbon dioxide ; nitrogen ; cold ; oviposition and mating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of anesthetizing with carbon dioxide, nitrogen, or low temperature on the reproductive behavior and fecundity of Callosobruchus subinnotatus was investigated. Males and females anesthetized with N2 as virgins had shorter recovery time, copulated earlier, and had shorter mating time than those subjected to CO2 or low temperature. Exposure of males and females to 2.0±0.5 °C for 10 min had the most profound effect on the recovery periods, copulation time, and duration of mating. Adults anesthetized with CO2 and low temperature laid fewer eggs than those anesthetized with N2. Females were more affected than males by the treatments, except when males were chilled for 10 min, and this prolonged the time for commencement of mating. The mode of anesthesia could affect egg production because vitellogenesis and choriogenesis take place in the imago stage of bruchids.
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    What is the basis of pederin polymorphism in Paederus riparius rove beetles? The endosymbiotic hypothesis (1999)
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 41-49 
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    ISSN: 1570-7458
    Keywords: Paederus riparius ; pederin polymorphism ; hemolymph toxin ; matrilineal trait ; endosymbionts ; cannibalism ; Staphylinidae ; Coleoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paederus riparius (Coleoptera:Staphylinidae) females are polymorphic with regard to their ability to synthesize the hemolymph toxin pederin, a character confined to that sex: (+)-females endow their eggs with pederin whereas (−)-females lay eggs devoid of the substance. When reared without access to conspecifics, (+)-females can only be obtained from (+)-mothers. Ingestion of (+)-eggs during larval development, however, enables the offspring of (−)-females to also become (+)-females. This is only the case if untreated (+)-eggs are eaten, while sterilized (+)-eggs do not alter larval fate as (−)-females. The character can thus be transferred to unrelated specimens. These experiments suggest that microorganisms might be involved in the biosynthesis of this unusual compound. Pederin appears to be the first defensive substance in insects traceable to endosymbionts.
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    Modifications in dispersal and oviposition of Bt-resistant and Bt-susceptible Colorado potato beetles as a result of exposure to Bacillus thuringiensis subsp. tenebrionis Cry3A toxin (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 93-101 
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    ISSN: 1570-7458
    Keywords: Colorado potato beetle ; Bacillus thuringiensis ; flight ; oviposition ; resistance management ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Laboratory strains of Colorado potato beetle, Leptinotarsa decemlineata (Say), physiologically resistant and susceptible to Bacillus thuringiensis (Berliner) subsp. tenebrionis Cry3A toxin were reared to adults on caged potato plants. Influence of three different diets (transgenic potatoes, regular potatoes, and regular potatoes followed by the transgenic potatoes) on beetle mortality, fecundity, and flight behavior were tested under laboratory conditions. A computer-linked flight mill system was used to quantify beetle flight, and dissections were performed to determine the level of flight muscle development. Susceptible beetles continuously fed on transgenic foliage suffered heavy mortality, did not develop flight muscles, and did not produce any eggs. Resistant beetles continuously fed on transgenic foliage were capable of flight and reproduction; however, it took them longer to initiate flight behavior, and their fecundity was lower than fecundity of other treatments. In both strains, detrimental effects became significantly less severe when the beetles were allowed to feed on regular foliage prior to toxin ingestion. In the resistant strain, ingestion of Cry3A toxin significantly increased flight activity, indicating that physiological resistance was probably reinforced by the behavioral escape from toxic environments. No such response was observed for susceptible beetles. When fed on regular foliage, resistant Colorado potato beetles engaged in significantly fewer flights than susceptible beetles. Behavioral differences between resistant and susceptible beetles observed in the present study are likely to affect gene flow between transgenic crops and adjacent refugia, and should be taken in consideration when designing resistance management plans for transgenic potato crops.
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    URL: http://dx.doi.org/10.1023/A:1003597616214
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    Physiology and costs of resistance to herbivory and disease in Brassica (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 231-237 
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    ISSN: 1570-7458
    Keywords: Leptosphaeria maculans ; Peronospora parasitica ; fungal pathogens ; Phyllotreta cruciferae ; flea beetles ; Coleoptera ; Chrysomelidae ; Cruciferae ; chitinase ; myrosinase ; allocation costs ; plant defense mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We used artificial selection experiments to study genetic allocation costs and physiological mechanisms of resistance to herbivory and fungal disease. Genetic costs to resistance were present in some instances and absent in others. Genetic resistance to the fungal pathogen, Leptosphaeria maculans was cost-free, while resistance to Peronospora parasitica showed a negative genetic correlation between disease resistance and growth rate. Leptosphaeria resistant genotypes had 13% higher chitinase activity. Genetic increases in myrosinase activity were correlated with increased resistance to flea beetles (Phyllotreta cruciferae), but resulted in lower plant fecundity, presumably due to production costs of myrosinase. Genetic costs of resistance may maintain genetic variation in natural plant populations. These studies demonstrate the predictive and explanatory power of a functional approach to plant-herbivore and plant-pathogen interactions.
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    URL: http://dx.doi.org/10.1007/BF00194764
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    Host selection behaviour of deathwatch beetle, Xestobium rufovillosum: Oviposition preference choice assays testing old vs new oak timber, Quercus sp. (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 193-199 
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    ISSN: 1570-7458
    Keywords: deathwatch beetle ; Xestobium rufovillosum ; Coleoptera ; Anobiidae ; Quercus sp. ; host selection behaviour ; oviposition ; timber pest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a choice bio-assay adult female deathwatch beetles were offered two dendrochronologically dated wood blocks from oak timber to study oviposition preference behaviour. There was a clear preference for ovipositing on old wood dating from the 13th to 19th centuries rather than new wood from the 20th century. Control, same-century choice, experiments showed that beetles will oviposit on young wood and that the age of the wood does not alter the overall oviposition potential. Oviposition frequency varied with insect age. Fecundity of insects collected from an infested building was similar to that of insects maintained in culture.
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    Tritrophic interactions among larval parasitoids, bruchids and Leguminosae seeds; influence of pre-and post-emergence learning on parasitoids' response to host and host-plant cues (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 293-296 
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    ISSN: 1570-7458
    Keywords: ectoparasitoids ; semiochemicals ; parasite host-selection ; Eupelmus vuilleti ; Hymenoptera ; Eupelmidae ; Dinarmus basalis ; Pteromalidae ; Coleoptera ; Bruchidae ; Bruchidius atrolineatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194778
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    Geographic variation in feeding and mating preferences in the Phratora tibialis complex (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 311-314 
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    ISSN: 1570-7458
    Keywords: leaf beetles ; Coleoptera ; Chrysomelidae ; feeding preference ; mating ; willows ; Salix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1007/BF00194781
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    Effects of host plant and cucurbitacin on growth of larval Diabrotica undecimpunctata howardi (1996)
    Springer
    Entomologia experimentalis et applicata 81 (1996), S. 47-51 
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    ISSN: 1570-7458
    Keywords: southern corn rootworm ; plant-insect interaction ; plant chemistry ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of host plant and dietary cucurbitacin on the growth of larval southern corn rootworm (SCR), Diabrotica undecimpunctata howardi Barber (Chrysomelidae: Luperini), were investigated. SCR were reared on four hosts: corn, Zea mays; peanuts, Arachis hypogaea; and two squash varieties, Cucurbita pepo cv. Ambassador (containing cucurbitacin D (0.08 mg g−1 fr.wt.) = bitter), and C. pepo cv. Early Yellow Crookneck (lacking cucurbitacin = non-bitter). Larval growth was significantly greater on corn and peanuts than on either squash variety. After four weeks, adults had emerged from corn and peanut plants, while squash-reared larvae had not yet entered the pupal stage. There was no difference in larval growth on the two varieties of squash. Primary metabolite measurements showed no nutritional differences between the two squash varieties. Artificial diet experiments were used to test the effect of three concentrations of cucurbitacin D (0.0, 0.1, and 0.6 mg g−1 diet) on growth of larval SCR. Larvae reared on diet containing 0.6 mg g−1 cucurbitacin weighed significantly less than larvae reared on diet containing 0.1 mg g−1 or no cucurbitacin after 10 d. No significant difference in growth was measured between the 0.1 mg g−1 diet and the 0.0 mg g−1 diet. Results are discussed relative to theories about the relationship between diabroticites and cucurbitacins.
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    Quiescence in the Colorado potato beetle, Leptinotarsa decemlineata (1997)
    Springer
    Entomologia experimentalis et applicata 82 (1997), S. 83-89 
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    ISSN: 1570-7458
    Keywords: Vibration detection ; sensitization ; habituation ; escape behaviour ; death feigning ; startle response ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Quiescence (death feigning) was induced in the Colorado potato beetle, Leptinotarsa decemlineata by mechanical disturbance of live and artificial plants on which beetles were walking, feeding or grooming. The response consisted of a sudden cessation of activity lasting 12 to 500 s. Recovery from this immobile state was usually preceded by either antennal or leg movement. The time taken for beetles to come out of the immobile state (i.e. recovery time) was not dependent on age or sex of beetles or on stimulus duration, but was dependent on degree of displacement and on satiation level. Repeated stimulations led to longer recovery times and to a smaller proportion of responding beetles. Stimulation within the immobile state also prolonged recovery time. The most effective frequency of mechanical disturbance for startling beetles was 30 Hz. This response is presumed to be part of the extensive defense repertoire of this beetle, but we have so far been unable to discover a natural enemy that will elicit it.
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    The effect of aphid prey quality on searching behaviour of Adalia bipunctata and its susceptibility to insecticides (1999)
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 277-282 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; Coccinellidae ; Adalia bipunctata ; Phorodon humuli ; Aphis fabae ; Aphis craccivora ; Aphis spiraephaga ; pyrethroids ; insect growth regulators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After consumption of one individual of a suitable prey, such as Phorodon humuli (Schrank) (Aphididae), Adalia bipunctata L. (Coleoptera, Coccinellidae) adults changed from extensive to intensive searching behaviour. However, after the consumption of one individual of three other aphid species: Aphis fabae Scop., Aphis craccivora Koch or Aphis spiraephaga Müller, which are unsuitable prey, this coccinellid remained immobile for 12–76 min and did not switch to intensive search after moving off. Adult A. bipunctata fed an unsuitable prey, A. fabae, for 2 weeks were 2–4 times more susceptible to pyrethroid insecticides (permethrin, deltamethrin, fenpropathrin, esfenvalerate, alfa-cypermethrin and bioresmethrin) and insect growth regulators (diflubenzuron, triflumuron, fenoxycarb, flufenoxuron, teflubenzuron) than those fed a suitable prey, P. humuli. The searching behaviour of coccinellids could thus be another criterion for determining the suitability of aphids as prey. The fact that the nutritional quality of aphids can affect the susceptibility of predatory coccinellids to insecticides should be borne in mind in integrated pest management programs.
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    Spring colonisation of orchards by Anthonomus pomorum from adjacent forest borders (1999)
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 131-139 
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    ISSN: 1570-7458
    Keywords: dispersal ; mark-release-recapture ; Anthonomus pomorum ; apple blossom weevil ; Coleoptera ; Curculionidae ; apple orchard
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The early-season dispersal of the overwintered apple blossom weevil, Anthonomus pomorum (L.) (Coleoptera: Curculionidae), is a crucial stage in the colonisation of dwarf apple orchards adjacent to forests. We have conducted release-recapture studies with 1700 to 4000 marked weevils at two orchard sites in Switzerland over 2 years to characterise the spatial and temporal pattern of the dispersal process. The dispersal and colonisation of orchards in spring by overwintered weevils is dependent upon the prevailing temperature. An orientated dispersal from the forest border to the centre of the orchard was observed consistently, irrespective of the angle of the apple tree rows with respect to the forest border or of climatic conditions. The average dispersal distance of the weevils was 19 m. Approximately one third of the weevil population remained on the first tree encountered, the remainder of the population moved over short distances mainly along the tree rows. This dispersal pattern led to a strong ‘edge effect’ with higher numbers of weevils occurring at the edges adjoining the forests as compared to the centre of orchards. The relevance of these findings to population dynamics and management of the pest is discussed.
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    Sequential sampling for adult coccinellids in wheat (1997)
    Springer
    Entomologia experimentalis et applicata 84 (1997), S. 267-273 
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    ISSN: 1570-7458
    Keywords: Insecta ; Coleoptera ; Coccinellidae ; population density ; timed counts ; quadrat sampling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult aphidophagous coccinellids are important predators of cereal aphids in wheat in the Great Plains of the United States for which sampling methods are needed to facilitate improved management. An equation relating the mean number of adult coccinellids per m2 in a wheat field to its variance was obtained using Taylor's power law. A sequential sampling procedure was developed to estimate the number of adult coccinellids per m2 with constant average statistical precision (standard error/mean). The procedure was constructed by an equation relating the number of adult coccinellids per m2 to the number of adult coccinellids per minute of counting incorporating into the Taylor's power law relationship. The procedure involves conducting a series of 1-min counts while walking through a field at a constant velocity of 10 m per minute. After each 1-min count sequential sampling stop-lines are consulted to determine if the specified level of precision has been achieved. Two methods, a statistical procedure and comparison with independent data, were used to assess the consistency with which the specified level of precision was achieved by the procedure. Results indicated that observed precision was close to that specified by the user over a wide range of adult coccinellid density.
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    Spring behavioral patterns of the apple blossom weevil (1996)
    Springer
    Entomologia experimentalis et applicata 79 (1996), S. 9-17 
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    ISSN: 1570-7458
    Keywords: Anthonomus pomorum ; temperature ; diel cycle ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Individual pairs of overwintered adult apple blossom weevils, Anthonomus pomorum (L.), confined with apple twigs under different ambient temperatures in the laboratory and on apple trees in the field, were observed through day and night for their spring activities. Flight behavior in relation to ambient temperature was also investigated under laboratory conditions using flight stands. Both sexes displayed predominantly nocturnal behavior patterns in both the laboratory and the field. Feeding, crawling, and mating activities increased following sunset in the field or onset of scotophase in the laboratory while resting occurred most frequently during daylight hours. Results of the laboratory experiments showed that temperature affected significantly the activity patterns. The diel pattern of activities became less distinctive at higher temperatures (above 15°C), and total activities in crawling, feeding, and mating were suppressed significantly at lower temperatures (below 5°C). Over 97% of the test weevils initiated take-off response from flight stands at 20°C within the 30 min trial period; however, flight initiation rarely occurred at temperatures 12°C or below. Overall, results of the laboratory and field experiments indicate that A. pomorum is a remarkably cold-adapted insect with ability to crawl, feed, and mate at a few degrees above freezing, a physiological attribute necessary for the exploitation of early stages of apple bud development in the cold early spring.
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    Treatment of adult Coleoptera with a chitin synthesis inhibitor affects mortality and development time of their progeny (1998)
    Springer
    Entomologia experimentalis et applicata 88 (1998), S. 31-39 
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    ISSN: 1570-7458
    Keywords: insecticide ; chitin synthesis inhibitors (CSIs) ; chlorfluazuron ; insect growth regulators (IGRs) ; bioassays ; Sitophilus oryzae ; Rhyzopertha dominica ; Coleoptera ; stored grain pests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A group of insect growth regulators, the chitin synthesis inhibitors (CSIs), are being more widely used as many insects have become resistant to broad-spectrum insecticides. This study investigated the mode of action of one CSI, particularly looking at the delayed effect of treating adult insects on the survival and development of their progeny. The study describes the responses of adult stored grain beetles Sitophilus oryzae (L.) (Curculionidae) and Rhyzopertha dominica (F.) (Bostrichidae) to wheat treated with chlorfluazuron. For both species, wheat treated with chlorfluazuron reduced progeny survival at a constant rate from 1 day to 8 weeks after it had been treated. There was a direct, negative concentration-time relationship between the treatment of the adults with chlorfluazuron-treated wheat and the survival and developmental rate of their progeny. Adults that were pre-exposed for one or more weeks before oviposition to wheat treated with chlorfluazuron had significantly lower progeny survival than adults that were not pre-exposed. The EC95 values were 16-fold higher for R. dominica and 40-fold higher for S. oryzae from assays without pre-exposure, than with pre-exposure. Pre-exposure of R. dominica with 0.1 mg kg-1 and of S. oryzae with 0.4 mg kg-1 of chlorfluazuron reduced progeny survival by 95%. Higher concentrations of chlorfluazuron produced a reduction in mean population developmental time of several days. These findings have important implications for bioassays of CSIs, since pre-exposure of the adults can significantly reduce the numbers of F1 progeny. Therefore standard bioassays may seriously underestimate the efficacy of the CSI being assayed.
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    URL: http://dx.doi.org/10.1023/A:1003274123052
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    Interaction of treatment of both adult and immature Coleoptera with a chitin synthesis inhibitor affects mortality and development time of their progeny (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 125-136 
    Details
    ISSN: 1570-7458
    Keywords: insecticide ; chitin synthesis inhibitors ; CSIs ; chlorfluazuron ; insect growth regulators (IGRs) ; bioassay ; pre-exposure ; Sitophilus oryzae ; Rhyzopertha dominica ; Coleoptera ; stored grain insect pests ; development time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chitin synthesis inhibitors, like many other insect growth regulating insecticides, do not kill adult insects but cause mortality of the immature stages. Pre-exposure of adult stored grain Coleoptera, Rhyzopertha dominica (F.) (Bostrichidae) and Sitophilus oryzae (L.) (Curculionidae) and development of their progeny in grain treated with the chitin synthesis inhibitor, chlorfluazuron, influenced the mortality and development rate of the progeny. Hatch rate of eggs from R. dominica adults that had both developed and laid on wheat treated with 0.75 mg kg−1 chlorfluazuron was reduced by almost 50% compared with untreated eggs, with an LC50 of 0.84 mg kg−1 . Eggs laid on treated wheat by R. dominica adults that had been exposed only to treated wheat for 2 weeks before oviposition showed greater reduction in hatch: 75% reduction of normal hatch rate at 0.25 mg kg−1 and almost 100% reduction at 2 mg kg−1 chlorfluazuron, with an LC50 of 0.19 mg kg−1 chlorfluazuron. X-rays were used to monitor the development and mortality of the immature stages of S. oryzae that developed within the wheat grains. Numbers of eggs laid were not affected by chlorfluazuron treatment. The combination of pre-exposure of adults and chlorfluazuron concentration had an additive effect on mortality of immature S. oryzae. Pre-exposure of adults caused most mortality in the first three weeks of development (eggs and larvae), whereas development in treated wheat caused mortality from weeks 3 to 8 (pupae and adults); higher concentrations of chlorfluazuron caused higher mortality. Development in wheat treated with 1 mg kg−1 chlorfluazuron caused 12% corrected overall mortality of progeny while pre-exposure to the same concentration and development in untreated wheat caused 29% corrected mortality. Pre-exposure combined with development in wheat treated with 1 mg kg−1 caused 30% corrected mortality. Thus, pre-exposure of adults appears to have a greater effect on mortality of S. oryzae progeny than development of immature stages in treated grain. Development on treated grain had no effect on development rate. Pre-exposure of adults did not appear to affect the rate of immature development, as assessed by X-rays, but did slow the emergence of adults, lengthening development time by about 2 days. This significant, additive effect of pre-exposure of adults on the mortality of their progeny will enhance the toxicity of chitin synthesis inhibitors such as chlorfluazuron, since most adults receive treatment when the immature stages are treated in crops either before they are harvested or in storage. Assessing the proportion of eggs that hatch from pre-exposed adults would be a simpler bioassay for CSIs.
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    Snowdrop and wheatgerm lectins and avidin as antimetabolites for the control of sugarcane whitegrubs (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 409-414 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; Scarabaeidae ; Antitrogus consanguineus ; Antitrogus parvulus ; avidin ; snowdrop lectin ; wheatgerm lectin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Snowdrop and wheatgerm lectins were found to be insecticidal and growth inhibiting dietary proteins for larvae of the sugarcane whitegrub Antitrogus parvulus. At concentrations as low as 0.5 mg of snowdrop lectin per gram of semi-artificial diet, growth was inhibited by 21 days of feeding and significant mortality was apparent by 28 days. Wheatgerm lectin was active at similar concentrations, although expression of the effects was slower. Avidin was found to be a growth inhibiting dietary protein for larvae of Antitrogus consanguineus. At levels as low as 0.01 mg g-1 of diet, growth was inhibited by 28 days of feeding. Avidin caused no significant mortality after 35 days of feeding. Snowdrop and wheatgerm lectins and avidin are insect growth-inhibiting proteins whose genes potentially could be manipulated into sugarcane and improve host-plant resistance to whitegrubs.
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    Response of first-instar Aleochara bilineata larvae to the puparium morphology of its dipteran host (1998)
    Springer
    Entomologia experimentalis et applicata 87 (1998), S. 217-220 
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    ISSN: 1570-7458
    Keywords: cabbage maggot ; Delia radicum ; Aleochara bilineata ; entrance hole distribution ; preference ; external puparium relief ; incidental protection ; host vulnerability ; Coleoptera ; Staphylinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1023/A:1003145304139
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    Effects of experimental stress factors on probing behaviour by aphids (1999)
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 289-300 
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    ISSN: 1570-7458
    Keywords: probing behaviour ; EPG ; stress ; starvation ; feeding interruption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Probing behaviour of Aphis fabae Scopoli and Rhopalosiphum padi (L.) was tested in different stress situations normally occurring in aphid-plant studies such as interruption of feeding or starvation, transfer to a new plant, and attachment to the electrode wire. The DC electrical penetration graph (EPG) technique and a ‘honeydew clock’ were used to collect data on behavioural effects of these stress conditions. As a general effect, an interruption of feeding behaviour acted as a ‘reset’, i.e., the same sequence and time course of probing events were shown, irrespective the interruptions duration, from 1–100 min. Nevertheless, some minor differences were found, especially in A. fabae. Increased interruption times (deprivation from the host plant) stimulated the aphids to insert their stylets earlier. When A. fabae was put back on its host plant after a one min interruption phloem feeding started earlier than with longer interruption times, but only when it was put back to the same plant and feeding site on which it fed before. It is concluded that this effect is at least partly due to ‘memory’ of previous probing/feeding experience on the plant as it vanishes with longer interruption times. This explanation also holds for phloem salivation (E1) before starting sustained sap ingestion, which was reduced on the previous feeding site, but only after the one min interruption in A. fabae. The aphid-plant specificity appeared high in these effects. Both aphids were somewhat affected by wiring, resulting in earlier probing, longer total pathway phase, and less and later phloem feeding (as reflected by honeydew excretion). Thus confirming, that the evaluation of EPG results can be improved with supplementary data from free aphids.
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    Pitfall-trap catches of the carabid beetle Pterostichus melanarius, in relation to gut contents and prey densities, in insecticide treated and untreated spring barley (1984)
    Springer
    Entomologia experimentalis et applicata 36 (1984), S. 23-30 
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    ISSN: 1570-7458
    Keywords: Pterostichus melanarius ; Coleoptera ; Carabidae ; pitfall traps ; insecticides ; prey ; hunger ; activity ; Rhopalosiphum padi ; Fenitrothion ; Sumicidin (Fenvalerate) ; spring barley
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Au cours d'essais à grande échelle, effectués en 1981 et 1982, sur orge de printemps, pour évaleur l'effet des insecticides Fenitrothion et Sumicidine (fenvalerate) sur les arthropodes utiles, un accroissement significatif des captures, dans des trappes pièges de Barber, de Pterostichus melanarius (Illiger) a été observé plusierus semaines après le traitement dans les lots traités par rapport aux lots témoins. Significativement plus de femelles de P. melanarius ont été capturées dans les parcelles traitées pendant cette période d'accroissement après traitement. Une diminution correspondante dans les populations de proies a été observée à la suite des traitements. Chaque femelle de P. melanarius des parcelles traitées avait une fraction significativement moins importance de son intestin remplie d'aliments solides (arthropodes) que celles des parcelles non traitées. Des auteurs précédents avaient observé des taux de capture plus rapides dans les trappes et ne plus grande mobilité des carabes affamés. La réduction des populations proies par l'application d'insecticides affamerait les carabes dont l'activité serait par suite plus élevée. Comme le taux de captures dans les trappes est dû à la fois à la taille de la population et à son activité, on en déduit que la capture par trappes seule ne peut donner une image exacte de l'effet des insecticides sur les populations de carabes dans les champs.
    Notes: Abstract During large-scale field experiments in 1981 and 1982, designed to assess the effects of the insecticides Fenitrothion and Sumicidin (Fenvalerate) on beneficial arthropods in spring barley, significant increases in pitfall-trap catches of Pterostichus melanarius (Illiger) were observed in treated plots compared to untreated controls, several weeks after treatment. Significantly more female P. melanarius were caught in treated plots during these post-treatment increases. Corresponding decreases were observed in prey populations following treatments. Individual female P. melanarius from treated plots had significantly fewer of their gut areas full of solid (arthropod) food when compared to those from untreated control plots. Earlier workers observed both faster recapture rates in pitfalls and higher mobility in hungry carabid beetles. The following hypothesis is suggested: reducing prey populations by the application of insecticides results in hungrier carabid beetles with consequently higher activity. Since pitfall-trap catch is determined not only by population size but also activity, it is argued that pitfall-trap catches alone cannot give a true measure of the effects of insecticides on carabid populations in the field.
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    Flight activity ofProstephanus truncatus (Horn) (Coleoptera: Bostrichidae) in relation to population density, resource quality, age, and sex (1996)
    Springer
    Journal of insect behavior 9 (1996), S. 339-351 
    Details
    ISSN: 1572-8889
    Keywords: Prostephanus truncatus ; larger grain borer ; Coleoptera ; Bostrichidae ; flight ; stored product insect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Higher flight activity has been observed in aged, high-density cultures ofProstephanus truncatus (Horn) (Coleoptera: Bostrichidae), but adults in new, lowdensity culture jars showed less flight activity. In order to understand this change in behavior, the effects of population density, age, resource quality, and sex on the flight ofP. truncatus were studied in a wind tunnel. While an immediate density on the release platform had no significant effect on flight, beetles from high-density cultures were more inclined to fly than those from low-density cultures. Resource quality exerted a major influence on flight; insects in food suitable for boring and oviposition seldomly exhibited flight, however, when food was absent or of inferior quality for boring and oviposition, the dominant behavior was flight. Also, insects maintained for a week in food suitable for boring and oviposition were less ready to fly than those maintained in food unsuitable for boring and oviposition. The optimum age range for flight activity was before the peak of reproduction and insects rarely flew before 4 days or after 32 days of emergence. There were no significant differences between the flight activity of males and that of females. Based on these results, we conclude that age and resource quality are major influences on the flight activity ofP. truncatus and a hypothesis is proposed in which reproductively active male and female beetles disperse from habitats of low resource quality to those that support their reproductive behavior. The practical implications of these results and the possible role of the male-produced aggregation pheromone are discussed.
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    Emergence, Mating, and Postmating Behaviors of the Oriental Beetle (Coleoptera: Scarabaeidae) (1999)
    Springer
    Journal of insect behavior 12 (1999), S. 175-192 
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    ISSN: 1572-8889
    Keywords: Coleoptera ; Scarabaeidae ; oriental beetle ; Exomala orientalis ; sustained-flight tunnel ; sex pheromone ; (Z)- and (E)-7-tetradecen-2-one ; mating behavior ; mate guarding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a previous field-trapping study of the oriental beetle, Exomala orientalis (Waterhouse), by using synthetic sex pheromone on golf course fairways, numerous males were observed and trapped during the hours of peak mating activity. However, very few beetles were observed in the same areas when synthetic pheromone was absent. To investigate the hypothesis that mating in nature occurs cryptically within vegetation at the soil surface, laboratory studies on female emergence and pheromone release, male emergence and mate-locating, and female and male mating behaviors were conducted. Mate acquisition and copulation occurred on the soil surface near the female emergence site, with both sexes engaging in pheromone-mediated behaviors after having emerged from the soil. A highly stereotyped female pheromone release, or calling, behavior was observed, consisting of insertion of the female's head into the soil and elevation of the tip of her abdomen into the air. Bioassays conducted in a wind tunnel that simulated a turf fairway environment showed that walking and flying were both important in the upwind response of males to females. Mating and copulation occurred without an obvious complex courtship, but observations of postmating behaviors suggested that mate guarding occurs.
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    Enhanced hydrogen peroxide sensitivity and altered stress protein expression in iron-starved Mycobacterium smegmatis (1997)
    Springer
    BioMetals 10 (1997), S. 215-225 
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    ISSN: 1572-8773
    Keywords: DnaK ; GroEL ; heat shock ; iron ; mycobacteria ; oxy-radicals ; peroxide ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1023/A:1018355928990
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    Response ofPhloeotribus scarabaeoides (Coleoptera, Scolytidae) to ethylene in an olfactometer (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 77-79 
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    ISSN: 1420-9071
    Keywords: Ethylene ; kairomone ; Phloeotribus scarabaeoides ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The role of ethylene, pure or in formulation, in the colonization behaviour of the olive bark beetle,Phloeotribus scarabaeoides (Coleoptera, Scolytidae) has been investigated in the laboratory. Ethylene has been found to be attractive in both sexes; the formulation ethrel 48 was active in an olfactometer up to several months. Ethylene, whose concentration varies with the developmental stage or the condition of the tree or its wood, may play an important role in the primary attraction of these scolytids to their host.
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    The effect of chronic heat stress on cortisol levels in the antarctic fishPagothenia borchgrevinki (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 768-774 
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    ISSN: 1420-9071
    Keywords: Cortisol ; stress ; heat ; Antarctic ; fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Radioimmunoassay was used to determine levels of the stress-inducible glucocorticoid, cortisol, circulating in the plasma of the extremely stenothermal Antarctic fishPagothenia borchgrevinki at rest and after heat stress. Fish sampled immediately after capture (−1.9°C) had low cortisol levels (10.4±1.4 ng ml−1, mean±SEM) as did fish which were laboratory rested for 3 days. Sudden exposure to 5°C (48h) resulted in a peak cortisol value after 3 h (69.9±6.8 ng ml−1) whereas exposure to 8°C (6h) resulted in a peak value after 1 h (73.5±8.0 ng ml−1). At both temperatures levels remained significantly elevated (p〈0.05) for the entire period of exposure. Increased temperature also resulted in a significant change in haemoglobin, haematocrit and mean cell haemoglobin concentration (MCHC) (p〈0.05). Plasma lactate was significantly elevated only after exposure to 8°C (p〈0.05). Plasma cortisol levels fromP. borchgrevinki are reported here for the first time and show this cryopelagic Antarctic species to have an unusual hormonal stress profile.
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    Nα-quinaldyl-L-arginine·HCl, a new defensive alkaloid fromSubcoccinella-24-punctata (Coleoptera, Coccinellidae) (1996)
    Springer
    Cellular and molecular life sciences 52 (1996), S. 628-630 
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    ISSN: 1420-9071
    Keywords: Coleoptera ; Coccinellidae ; Subcoccinella-24-punctata ; chemical defense ; quinoline alkaloid ; Nα-quinaldyl-L-arginine·HCl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The isolation of Nα-quinaldyl-L-arginine·HCl (1) from the CoccinellidaeSubcoccinella-24-punctata is reported. The structure, first established on the basis of the analysis of the spectral properties of1, has been confirmed by synthesis. The alkaloid is of endogenous origin and markedly deterrent to ants.
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    Rapid development and a long life: an association expected under a stress theory of aging (1996)
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    Cellular and molecular life sciences 52 (1996), S. 643-646 
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    ISSN: 1420-9071
    Keywords: Aging ; development time ; stress ; energy cost ; oxidative stress ; Drosophila ; homeostasis ; life span
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Life span and development time are considered in the context of the abiotic stresses to which free-living organisms are normally exposed. Under these circumstances, long life span depends upon metabolically efficient stress-resistance genes, which tend to be heterozygous. Similarly, rapid development time tends to be a feature of heterozygous stress-resistant individuals. Therefore, individuals who have high inherited stress resistance should develop fastest and live longest; in addition, they should show high homeostasis in the face of the energy costs of stress. In this way, the stress theory of aging can incorporate the developmental stage, based upon oxidative stress as an important major direct challenge.
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    Ecdysteroids during pupal development of female Xyleborus ferrugineus (1981)
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    Entomologia experimentalis et applicata 30 (1981), S. 151-156 
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    ISSN: 1570-7458
    Keywords: Xyleborus ferrugineus ; pupae ; ecdysteroids ; pharate adult ; radioimmunoassay ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Der Ecdysteroidtiter weiblicher Puppen von Xyleborus ferrugineus (Fabr.) wurde geschätzt, indem ganze Tiere homogenisiert und radioimmunologisch untersucht wurden. Ein ausgeprägtes Maximum an Ecdysteroiden wurde bei 36 Stunden Puppenent-wicklung beobachtet (743 pg/mg Körpergewicht). Der Titer nahm ab auf 299 pg/mg im Pharatstadium und auf 193 pg/mg unmittelbar vor Schlüpfen der Adulten. Qualitative Studien mit HPLC ergaben in frischen Puppen ein Verhältnis von 3:1 Ecdyson zu 20-Hydrooxyecdyson. Pharatstadien enthielten vor allem 20-Hydrooxyecdyson. Das beobachtete einzige Maximum im Titer stimmt überein mit den Resultaten bei andern untersuchten Coleopteren.
    Notes: Abstract Ecdysteroid titers were estimated on the whole body homogenates of Xyleborus ferrugineus (Fabr.) female pupae during development by radioimmunoassay. A distinct peak of ecdysteroids was observed at 36-hr pupal development (743 pg/mg body wt). Titer declined to 299 pg/mg by the pharate adult stage and to 193 pg/mg body wt just before adult emergence. Qualitative studies by HPLC revealed a ratio of 3:1 ecdysone to 20-hydroxyecdysone in the initial pupal stage. Pharate adults had mainly 20-hydroxyecdysone. The observed single peak in ecdysteroid titer agrees with findings in other studied coleopteran species.
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    The feeding characteristics and development of larvae of a salvinia weevil Cyrtobagous sp. (1983)
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 291-296 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Cyrtobagous ; Salvinia weevil ; Feeding characteristics of larvae ; Development of larvae ; Plant nutrition ; Temperature effects on development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Après leur naissance, les larves de Cyrtobagous sp. passent de 1 à 4 jours à brouter les racines, et de 0 à 9 jours dans les bourgeons de la plante hôte, Salvinia molesta, avant d'y creuser une galerie dans le rhizome. Bien que les larves aient été capables de survivre jusqu'à 38 jours en broutant les racines, quant elles furent privées de rhizome, elle ne purent achever leur développement. Quand les galeries furent commencées, le développement larvaire, entre 21° et 31°, dépendit de la température et de la teneur en azote de l'hôte. Les larves ne se développèrent pas à 17°. Une haute valeur nutritive de l'aliment consommé par les larves réduisit la durée du développement, mais n'influença pas la durée ultérieure de leur développement nymphal. Les lieux de prise de nourriture et les dégâts produits par des larves isolées furent précisés.
    Notes: Abstract Newly-emerged larvae of a salvinia weevil, Cyrtobagous sp. spent from 1–4 days browsing on the roots and from 0–9 days in the buds of the host plant, Salvinia molesta, prior to tunnelling into the rhizome of this aquatic weed. Although larvae were able to survive up to 38 days browsing on roots when rhizomes were withheld, they were unable to complete development. After tunnelling began, larval development between 21° and 31° was dependent on temperature and nitrogen levels in the host. Larvae failed to develop at 17°. High nutritional intake by the larvae reduced larval development time but did not influence duration of their subsequent pupal development. The feeding sites and plant damage produced by individual larvae were assessed.
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    Distribution of proteinases and carbohydrases in the midgut of larvae of the sweetpotato weevilCylas formicarius elegantulus and response of proteinases to inhibitors from sweet potato (1984)
    Springer
    Entomologia experimentalis et applicata 36 (1984), S. 97-105 
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    ISSN: 1570-7458
    Keywords: Coleoptera ; Curculionidae ; Cylas formicarius elegantulus ; sweetpotato weevil ; sweet potato ; digestion ; enzyme distribution ; trypsin-inhibitors ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'activité endoprotéinase était limitée au liquide de la lumière des régions ventriculaires antérieure et postérieure de l'intestin moyen des larves deCylas formicarius elegantulus Summers. Les aminopeptidases ont été trouvées dans le liquide de la lumière (18%), mais étaient principalement associées avec les fractions insolubles des cellules du ventricule postérieur (82%). Suivant le substrat, l'activité carboxypeptidase était à peu près également répartie entre le liquide de la lumière et les fractions insolubles des cellules du ventricule postérieur. L'amylase, enzyme secrétée, a été observée à la fois dans la lumière antérieure et postérieure. Cinq bandes d'activité amylase ont été révélées sur zymogrammes d'amidon après électrophorèse d'intestins moyens entiers. Trois des bandes d'amylase pouvaient provenir de la plante. Il y avait au moins 2 α-glucosidases, une secrétée et une liée aux cellules du ventricule antérieur. L'activite β-glucosidase était liée aux cellules du ventricule antérieur, fandis que l'activité α-galactosidase était limitée au fluide de la lumière. Les activités β-galactosidase et cellulase ont été trouvées à la fois dans le liquide de la lumière et dans la fraction cellulaire insoluble. Ainsi, la digestion initiale des grosses protéines et des polymères de carbohydrates se produit dans le liquide de la lumière dans les régions ventriculaires antérieure et postérieure. Cependant, l'achèvement de la digestion des oligopeptides se produit principalement dans le ventricule postérieur, tandis que la fin de la digestion des oligosaccharides se produit dans le ventricule antérieur. Les concentrations en inhibiteurs de trypsine de 5 cultivars d'I. batatas L. diffèrent de 1 à 20. Les endoprotéinases deC. formicarius elegantulus ont été inhibées par des extraits de cultivars, mais les cultivars avec des concentrations relativement élevées d'inhibiteur avainent antérieurement montré être susceptibles d'être attaqués par le coléoptère dans des essais en champs.
    Notes: Abstract Endoproteinase activity was confined to luminal fluid from anterior and posterior ventricular regions of midguts of larvae of the sweetpotato weevil,Cylas formicarius elegantulus (Summers). Aminopeptidase was found in luminal fluid (18%) but was primarily associated with insoluble fractions from cells of the posterior ventriculus (82%). Depending on substrate, carboxypeptidase activity was about equally distributed between luminal fluid and insoluble fractions from posterior ventriculus cells. Amylase was found in luminal fluid in both the anterior and posterior ventriculus. Five bands of amylase activity were detected on starch zymograms following electrophoresis of whole midgut samples. Three of the amylase bands may be plant-derived. At least two α-glucosidases were present, one secreted and one bound to anterior ventriculus cells. β-Glucosidase activity was bound to anterior ventriculus cells whereas α-galactosidase activity was confined to luminal fluid. β-Galactosidase and cellulase activities were found in both luminal fluid and the insoluble cell fraction. Thus, initial digestion of large protein and carbohydrate polymers occurs in luminal fluid in both anterior and posterior ventriculus regions. However, terminal digestion of oligopeptides occurs primarily in the posterior ventriculus while terminal digestion of oligosaccharides occurs in the anterior ventriculus. A 20-fold difference in trypsin-inhibitor concentration was found among five sweetpotato cultivars. Endoproteinases from sweetpotato weevil larvae were inhibited by extracts from the cultivars but cultivars with relatively high concentrations of inhibitor were previously shown to be susceptible to weevil attack in field trials.
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    URL: http://dx.doi.org/10.1007/BF00569949
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    A new, X-linked body colour mutation in Tribolium confusum (1983)
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 124-126 
    Details
    ISSN: 1570-7458
    Keywords: Negret ; Melanic mutant ; X-linked mutation ; Flour Beetle ; Tribolium confusum ; Coleoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300913
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    Responses of Prostephanus truncatus to components of the aggregation pheromone of Rhyzopertha dominica in the laboratory and field (1983)
    Springer
    Entomologia experimentalis et applicata 34 (1983), S. 266-272 
    Details
    ISSN: 1570-7458
    Keywords: Storage pests ; Coleoptera ; Bostrichidae ; Prostephanus truncatus ; (±)-1-methylbutyl (E)-2-methyl-2-pentenoate ; Rhyzopertha dominica ; (±)-1-methyl-butyl (E)-2,4-dimethyl-2-pentenoate ; Dominicalure ; Aggregation pheromone ; Monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les réponses de Prostephanus truncatus Horn (Coleoptera: Bostrichidae) à deux constituants de la phéromone d'agrégation de Rhyzopertha dominica Fabricius (Coleoptera: Bostrichidae), le (±)-1-méthylbutyl (E)-2-méthyl-2-penténoate et le (±)-1-méthylbutyl (E)-2,4-diméthyl-2-pentéoate, connus comme “Dominicalure 1” et “Dominicalure 2”, ont été étudiées au laboratoire et au champ. Auslaboratoire ces composés ont été essayés individuellement et en mélange 1:2. Une membrane de caoutchouc imprégnée de phéromone a été utilisée comme émetteur lent, et une courbe de réponse en fonction de la dose a été établie. P. truncatus répondait plus vigoureusement à la Dominicalure 2 seule. Tous ces traitements ont été comparés dans un essai aux champs en Tanzanie, dans lesquels des pièges en carton ondulé contenant des diffuseurs de phéromone étaient placés dans des entrepôts de maïs dans les fermes. La Dominicalure 1 et le mélange de 1 et 2 étaient tous deux efficaces pour piéger R. dominica. La Dominicalure 2 a piégé plus de P. truncatus que les autres traitements et était à peu près aussi efficace que le contrôle visuel pour détecter la présence de cet insecte dans les stocks. On peut envisager que la Dominicalure 2 pourrait servir de base à un programme pour lutter contre P. truncatus en Afrique de l'Est.
    Notes: Abstract Laboratory and field studies have been made of the responses of Prostephanus truncatus (Horn) to two components of the aggregation pheromone of Rhyzopertha dominica (Fabricius) — (±)-1-methylbutyl (E)-2-methyl-2-pentenoate and (±)-1-methylbutyl (E)-2,4-dimethyl-2-pentenoate, known as “Dominicalure 1” and “Dominicalure 2” respectively. In the laboratory, these compounds were tested individually and as a 1:2 mixture; P. truncatus responded most strongly to Dominicalure 2 alone. All three treatments were compared in a field trial in Tanzania to monitor both R. dominica and P. truncatus in farm stores. Dominicalure 1 or a mixture of 1 and 2 were both highly effective for trapping R. dominica. In contrast, Dominicalure 2 trapped more P. truncatus than the other treatments and was about as effective as visual inspection at demonstrating the presence of the beetle in stores. Dominicalure 2 could form the basis of a monitoring programme for P. truncatus in East Africa.
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    Circadian Rhythm and the Business Person (1998)
    Springer
    International journal of value-based management 11 (1998), S. 9-17 
    Details
    ISSN: 1572-8528
    Keywords: circadian ; flextime ; memory ; productivity ; time-of-day ; rhythm ; preference ; stress ; efficiency ; Zeitgeber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract Each human being has an internal timekeeping mechanism. To date, over 100 so-called ‘circadian’ rhythms have been detected. Perhaps the most significant is body temperature. There is an apparent connection between this rhythm and the efficiency with which we do things in the course of the working day. Within individuals, patterns have been discovered which give credence to the popular notions of a ‘morning’ or an ‘afternoon’ person, and so on. Our memory changes from morning to afternoon: short-term memory is stronger in the morning, and long-term memory stronger in the afternoon; in schools, ‘morning’ students have higher grades than students who have other time-of-day preferences. Therefore, a strong case can be made in support of flexible time schedules. It is reported that productivity went up on the introduction of such a scheme. Employee stress has been seen to decline also. When flextime was offered, parents with small children took advantage of the benefit as well as unmarried employees. The only drawback is ensuring that, with so many individual variations in preferences, the needs of the company are fully met. If such a scheme can be devised, however, the research suggests that productivity and efficiency will increase.
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    URL: http://dx.doi.org/10.1023/A:1007714119076
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    Growth response of lentil and wheat to Glomus clarum NT4 over a range of P levels in a Saskatchewan soil containing indigenous AM fungi (1997)
    Springer
    Mycorrhiza 7 (1997), S. 3-8 
    Details
    ISSN: 1432-1890
    Keywords: Key words Glomus clarum NT4 ; Lentil ; Wheat ; Indigenous AMF ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The growth responses of lentil (Lens esculenta L. cv. Laird) and two wheat cultivars (Triticum aestivum L. cv. Laura and Neepawa) to Glomus clarum NT4 in soil containing indigenous arbuscular mycorrhizal fungi (AMF) and fertilized with phosphorus at different (0, 5, 10, 20 ppm) levels was studied in a growth chamber. Soil was inoculated with a monospecific culture of G. clarum NT4 to provide an inoculant:indigenous AMF ratio of ca. 1 : 100. The shoot and root growth, and AMF colonization levels of NT4-inoculated lentil were significantly (P≤0.05) greater than the appropriate control plants in the unfertilized soil at 48 days after planting (DAP). At 95 DAP, NT4 inoculation had significantly increased the shoot dry weight (P≤0.08) and AMF colonization (P≤0.05) of lentil plants receiving 5 mg P kg–1 soil, whereas 20 mg P kg–1 soil reduced the shoot growth of NT4-inoculated plants. The NT4 inoculant had no effect (P≤0.05) on shoot P content, but increased (P≤0.08) the P-use efficiency of lentil plants receiving 5 mg P kg–1 soil. In contrast to the inoculant's effect on lentil, NT4 generally had no positive effect on any of the parameters assessed for wheat cv. Laura at any P level at 48 or 95 DAP. Similarly, there was no positive effect of NT4 on shoot or root growth, or AMF colonization of wheat cv. Neepawa plants at any P level at 48 DAP. However, NT4 inoculation increased the grain yield of Neepawa by 20% (P≤0.05) when fertilized with 20 mg P kg–1 soil. This yield increase was associated with a significant (P≤0.05) reduction in root biomass and a significant (P≤0.05) increase in the grain P content of inoculated plants. Thus, NT4 appears to have a preference for the Neepawa cultivar. Our results show that lentil was more dependent on mycorrhizae than wheat and responded to an AMF inoculant even in soil containing high levels of indigenous AMF. It might, therefore, be possible to develop mixed inoculants containing rhizobia and AMF for field production of legumes.
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    URL: http://dx.doi.org/10.1007/s005720050156
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    Comparison of pyrites varying in water-soluble sulfur with gypsum for the reclamation of alkali soils under a rice-wheat rotation (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 96-101 
    Details
    ISSN: 1432-0789
    Keywords: Pyrites ; Pyrite oxidation ; Gypsum Alkali soil ; Reclamation ; Soluble sulfur Welland rice ; Wheat ; Thiobacillus thioxidans ; Thiobacillus ferrooxidans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We evaluated the effect of agricultural-grade (AG) pyrites (total sulfur 22%) varying in water-soluble sulfur (1–8%) and gypsum on the soil properties and yields of rice and wheat in alkali soils during the years 1993–1995 at the Gudha and Saraswati experimental farms at the Central Soil Salinity Research Institute, Karnal, India. Gypsum and pyrites were applied on the basis of gypsum requirement (GR) of the soils. Results showed that the efficiency of AG pyrites in decreasing soil pH and exchangeable sodium percentage (ESP) and increasing crop yields was dependent on their water-soluble sulfur content at the time of application to the field. Pyrites with 5.5% and 8% soluble sulfur were as effective as gypsum. The freshly mined pyrite (water-soluble S 1%) was found to be inefficient in reclaiming alkali soils. We also explored the possibility of increasing the water-soluble sulfur content of pyrite by optimizing its storage conditions. When pyrite (1% water-soluble S) was stored under moist conditions by sprinkling water over the bags under a rain shelter, there was an enrichment of indigenous iron- and sulfur-oxidizing bacteria of pyrite, and the water-soluble sulfur increased to 5% within a period of 6 months. However no such increase occurred when pyrite was stored dry. We conclude that the soluble sulfur content of pyrite increased during its storage under moist conditions and should be between 6% and 8% at the time of its application to the field.
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    URL: http://dx.doi.org/10.1007/BF01420227
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    Comparison of pyrites varying in water-soluble sulfur with gypsum for the reclamation of alkali soils under a rice-wheat rotation (1996)
    Springer
    Biology and fertility of soils 24 (1996), S. 96-101 
    Details
    ISSN: 1432-0789
    Keywords: Key words Pyrites ; Pyrite oxidation ; Gypsum ; Alkali soil ; Reclamation ; Soluble sulfur ; Wetland rice ; Wheat ; Thiobacillus thioxidans ; Thiobacillus ferrooxidans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We evaluated the effect of agricultural-grade (AG) pyrites (total sulfur 22%) varying in water-soluble sulfur (1–8%) and gypsum on the soil properties and yields of rice and wheat in alkali soils during the years 1993–1995 at the Gudha and Saraswati experimental farms at the Central Soil Salinity Research Institute, Karnal, India. Gypsum and pyrites were applied on the basis of gypsum requirement (GR) of the soils. Results showed that the efficiency of AG pyrites in decreasing soil pH and exchangeable sodium percentage (ESP) and increasing crop yields was dependent on their water-soluble sulfur content at the time of application to the field. Pyrites with 5.5% and 8% soluble sulfur were as effective as gypsum. The freshly mined pyrite (water-soluble S 1%) was found to be inefficient in reclaiming alkali soils. We also explored the possibility of increasing the water-soluble sulfur content of pyrite by optimizing its storage conditions. When pyrite (1% water-soluble S) was stored under moist conditions by sprinkling water over the bags under a rain shelter, there was an enrichment of indigenous iron- and sulfur-oxidizing bacteria of pyrite, and the water-soluble sulfur increased to 5% within a period of 6 months. However no such increase occurred when pyrite was stored dry. We conclude that the soluble sulfur content of pyrite increased during its storage under moist conditions and should be between 6% and 8% at the time of its application to the field.
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    Interaction of 15N-labelled ammonium nitrate, urea and ammonium sulphate with soil N during growth of wheat (Triticum aestivum L.) under field conditions (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 185-189 
    Details
    ISSN: 1432-0789
    Keywords: 15N-labelled fertilizer ; Added N interaction Fertilizer N uptake ; Soil N uptake ; Wheat ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of 15N-labelled ammonium nitrate, urea and ammonium sulphate on yield and uptake of labelled and unlabelled N by wheat (Triticum aestivum L. cv. Mexi-Pak-65) were studied in a field experiment. The dry matter and N yields were significantly increased with fertilizer N application compared to those from unfertilized soil. The wheat crop used 64.0–74.8%, 61.5–64.7% and 61.7–63.4% of the N from ammonium nitrate, urea and ammonium sulphate, respectively. The fertilizer N uptake showed that ammonium nitrate was a more available source of N for wheat than urea and ammonium sulphate. The effective use of fertilizer N (ratio of fertilizer N in grain to fertilizer N in whole plant) was statistically similar for the three N fertilizers. The application of fertilizer N increased the uptake of unlabelled soil N by wheat, a result attributed to a positive added N interaction, which varied with the method of application of fertilizer N. Ammonium nitrate, urea and ammonium sulphate gave 59.3%, 42.8% and 26.3% more added N interaction, respectively, when applied by the broadcast/worked-in method than with band placement. A highly significant correlation between soil N and grain yield, dry matter and added N interaction showed that soil N was more important than fertilizer N in wheat production. A values were not significantly correlated with added N interaction (r=0.719). The observed added N interaction may have been the result of pool substitution, whereby added labelled fertilizer N stood proxy for unlabelled soil N.
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    Solubilization of hydroxyapatite by Enterobacter agglomerans and cloned Escherichia coli in culture medium (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 347-352 
    Details
    ISSN: 1432-0789
    Keywords: Key words Phosphate-solubilizing bacteria ; Hydroxyapatite ; Enterobacter agglomerans ; Organic acids ; Phosphate-solubilizing genes ; Rhizosphere ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phosphate-solubilizing bacteria (PSB) possessing the ability to solubilize insoluble inorganic phosphate were isolated from the rhizosphere soil of wheat. A laboratory study was conducted to investigate the solubilization of phosphate by a known PSB, Enterobacter agglomerans, and by a genetically manipulated bacterium, Escherichia coli. A second laboratory study investigated the release of P from E. agglomerans compared with known acids. For the first laboratory study, a cosmid (pHC79) library of phosphate-solubilizing gene(s) from E. agglomerans chromosome DNA was constructed in E. coli JM109. The clone JM109 (pKKY) showing phosphate solubilization properties was screened on standard medium containing hydroxyapatite (HY). The P concentration significantly increased at 5 and 10 days for JM109 (pKKY) compared with JM109 (pHC79), the control. Although the P concentration increased, there was no significant change in their pHs. Furthermore, an increase in colony-forming units (CFUs) was seen at 5 and 10 days for JM109 (pKKY) but not for JM109 (pHC79). Artificial acidification of the culture medium with HCl, citric acid, oxalic acid, and lactic acid was achieved by shaking for 48h. Acidification with these selected acids solubilized more HY than E. agglomerans growing for 42h at similar pHs. However, a high P concentration was measured in culture medium with E. agglomerans growing for 84h despite similar pHs. Our results suggest that acid production may play an important role in HY solubilization, but is not the sole reason for the increase in P concentration in culture medium.
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    Increased emergence of spring wheat after inoculation with Pseudomonas chlororaphis isolate 2E3 under field and laboratory conditions (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 200-206 
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    ISSN: 1432-0789
    Keywords: Key words Plant growth-promoting rhizobacteria ; Pseudomonas spp. ; Wheat ; Rhizoctonia solani
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inoculation at the time of planting with Pseudomonas chlororaphis strain 2E3 increased the emergence of spring wheat by 8% and 6% at two different sites in northern Utah. Isolate 2E3 strongly inhibited the growth of the wheat pathogen Fusarium culmorum on artificial media. A second isolate of P. chlororaphis (strain O6) also inhibited fungal growth on artifical media but did not increase emergence of the spring wheat at the same field sites. Inoculation of winter wheat by 2E3 did not promote emergence when planted into field soil sterilized by fumigation with methyl bromide. Under laboratory conditions, emergence of spring wheat in sterilized soils from both sites was at least 90%. In the soils that were not sterilized, emergence was below 25% in soil from one site and below 50% in soil from the other. Treating seeds with 2E3 significantly improved emergence in a sterile soil-containing matrix that had been inoculated with the wheat pathogen Fusarium culmorum. Consequently, we propose that increases in wheat emergence can be attributed to the suppression by 2E3 of pathogenic organisms present in the native field soils. A strain of Rhizoctonia solani, shown to the pathogenic on winter wheat, was isolated from one of these soils.
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    Gram-positive bacterial flora on the root surface of wheat (Triticum aestivum L.) grown under different soil conditions (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 121-125 
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    ISSN: 1432-0789
    Keywords: Wheat ; Rhizosphere ; Soil Microflora ; Gram-positive Bacteria ; Coryneform Bacteria ; Arthrobacter spp. ; Mol% G+C ; Diaminopimelic acid ; DAP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We identified 108 Gram-positive bacterial strains isolated from the root surface of wheat grown under different soil conditions. The strains were divided into four groups based on morphological and physiological characteristics, but most appeared to be coryneform. The taxonomic position of the various groups was verified by the guanine+cytosine DNA contents of the strains. In general, the ranges of these values agreed with those described for the respective taxonomic positions in the literature, with a few exceptions. With soil improvement the distribution of the various groups on the root surface changed, with the coryneform group becoming dominant. This group was further divided into five subgroups, according to cell wall components, cellulose-decomposition, and morphological characteristics, and were identified to genus level. The distribution of these subgroups on the root surface of wheat did not alter with soil improvement. The genus Arthrobacter, the dominant subgroup, predominated in every plot.
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    Increased emergence of spring wheat after inoculation with Pseudomonas chlororaphis isolate 2E3 under field and laboratory conditions (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 200-206 
    Details
    ISSN: 1432-0789
    Keywords: Plant growth-promoting rhizobacteria ; Pseudomonas spp. ; Wheat ; Rhizoctonia solani
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inoculation at the time of planting with Pseudomonas chlororaphis strain 2E3 increased the emergence of spring wheat by 8% and 6% at two different sites in northern Utah. Isolate 2E3 strongly inhibited the growth of the wheat pathogen Fusarium culmorum on artificial media. A second isolate of P. chlororaphis (strain O6) also inhibited fungal growth on artifical media but did not increase emergence of the spring wheat at the same field sites. Inoculation of winter wheat by 2E3 did not promote emergence when planted into field soil sterilized by fumigation with methyl bromide. Under laboratory conditions, emergence of spring wheat in sterilized soils from both sites was at least 90%. In the soils that were not sterilized, emergence was below 25% in soil from one site and below 50% in soil from the other. Treating seeds with 2E3 significantly improved emergence in a sterile soil-containing matrix that had been inoculated with the wheat pathogen Fusarium culmorum. Consequently, we propose that increases in wheat emergence can be attributed to the suppression by 2E3 of pathogenic organisms present in the native field soils. A strain of Rhizoctonia solani, shown to the pathogenic on winter wheat, was isolated from one of these soils.
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    Fate and recovery of 15N derived from grass/clover residues when incorporated into a soil and cropped with spring or winter wheat for two succeeding seasons (1997)
    Springer
    Biology and fertility of soils 25 (1997), S. 130-135 
    Details
    ISSN: 1432-0789
    Keywords: Key words Grass/clover residues ; Nitrogen 15N ; N mineralization-immobilization ; N recovery ; Particle size fractionation ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The fate of N when 15N-labelled perennial ryegrass/white clover residues were incorporated into field lysimeters (rate equivalent to 150kgNha–1) and two successive crops of winter or spring wheat were grown was investigated. Loss of 15N over the first winter amounted to 23% and 22% respectively for winter and spring wheat and corresponding losses in the 2nd year were 10% and 14%. Both winter- and spring-sown crops recovered about 10% of residue 15N in the first season and about 1.5% in the second. The percentage of total crop N uptake originating from residue 15N was only 14% and 12% respectively for winter and spring wheat in the first season and 2.5% and 1.9% respectively for the second season. The bulk of the 15N recovered was incorporated into the soil organic matter fraction and at harvest of the 2nd year 55% of added 15N was present as soil organic N. In order to investigate the nature of this soil organic 15N, soil was fractionated into different particle size separates. Both 14N and 15N were concentrated in the medium and fine silt and coarse, and to a lesser extent, medium and fine clay fractions. However, in spring of the first season, 15N was preferentially present in the floating organic matter and to a lesser extent sand-sized fractions (i.e. as particles of decomposing residue). Between then and harvest of the second season there was a redistribution of 15N from these fractions and the medium- and fine-sized clay particles toward the coarse and medium silt-sized fractions. This suggested a movement of 15N toward more aromatic humified material in silt-sized fractions and away from decomposing organic material in sand separates and away from labile organic material in the clay-sized fractions. A laboratory incubation experiment showed that the availability (percentage mineralization) of recently immobilized 15N was greater than that of native soil 14N.
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    Growth and yield responses of a Nepalese spring wheat cultivar to the inoculation with Nepalese Azospirillum spp at various levels of nitrogen fertilization (1997)
    Springer
    Biology and fertility of soils 26 (1997), S. 72-77 
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    ISSN: 1432-0789
    Keywords: Key wordsAzospirillum ; Inoculation response ; Nitrogenase activity ; Nitrogen fertilizer ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The Azospirillum 10SW used in our experiments was isolated from roots of wheat growing in nitrogen-poor soil of a hilly region of Nepal, where inorganic nitrogen fertilizers were never used. The main objectives of this work were to assess the effects of inorganic nitrogen fertilization in the yield responses of wheat grown in association with the bacteria. The in vitro experiments were done in laboratory, whereas the pot experiments were performed in a greenhouse. The nitrogenase activities of in vitro grown Azospirillum were repressed by nitrate. The magnitude of repression was lower when the bacteria were growing in association with wheat. The number of roots per plant was increased significantly in inoculated plants irrespective of the nitrate concentration of the medium. Inoculation with Azospirillum 10SW also increased the yield of wheat grown in pots with medium levels of nitrogen fertilization. These data show the possibility of inoculation of this Azospirillum spp. in combination with nitrogen fertilizer to improve the yield of wheat. Azospirillum inoculation enhanced the development of roots and shoots in the early growth stages of wheat. It may be one of the factors responsible for the yield increases.
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    Nitrous oxide emissions from an irrigated sandy-clay loam cropped to maize and wheat (1998)
    Springer
    Biology and fertility of soils 27 (1998), S. 189-196 
    Details
    ISSN: 1432-0789
    Keywords: Key words Irrigation ; Maize ; Nitrous oxide ; Urea ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Nitrous oxide (N2O) emissions were measured from an irrigated sandy-clay loam cropped to maize and wheat, each receiving urea at 100 kg N ha–1. During the maize season (24 August–26 October), N2O emissions ranged between –0.94 and 1.53 g N ha–1 h–1 with peaks during different irrigation cycles (four) ranging between 0.08 and 1.53 g N ha–1 h–1. N2O sink activity during the maize season was recorded on 10 of the 29 sampling occasions and ranged between 0.18 and 0.94 g N ha–1 h–1. N2O emissions during the wheat season (22 November–20 April) varied between –0.85 and 3.27 g N ha–1 h–1, whereas peaks during different irrigation cycles (six) were in the range of 0.05–3.27 g N ha–1 h–1. N2O sink activity was recorded on 14 of the 41 samplings during the wheat season and ranged between 0.01 and 0.87 g N ha–1 h–1. Total N2O emissions were 0.16 and 0.49 kg N ha–1, whereas the total N2O sink activity was 0.04 and 0.06 kg N ha–1 during the maize and wheat seasons, respectively. N2O emissions under maize were significantly correlated with denitrification rate and soil NO3 –-N but not with soil NH4 +-N or soil temperature. Under wheat, however, N2O emissions showed a strong correlation with soil NH4 +-N, soil NO3 –-N and soil temperature but not with the denitrification rate. Under either crop, N2O emissions did not show a significant relationship with water-filled pore space or soil respiration.
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    Solubilization of inorganic phosphates and growth emergence of wheat as affected by Azotobacter chroococcum mutants (1999)
    Springer
    Biology and fertility of soils 28 (1999), S. 301-305 
    Details
    ISSN: 1432-0789
    Keywords: Key words Azotobacter chroococcum ; Inorganic phosphate solubilization ; Indole acetic acid ; Growth emergence ; Wheat ; Phytohormone production ; Rhizosphere ; Phosphate solubilizing bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Phosphate-solubilizing strains of A. chroococcum isolated from the wheat rhizosphere were evaluated for their ability to solubilize tricalcium phosphate (TCP), Mussoorie rock phosphate (MRP) and also for indole-acetic-acid (IAA) production. Strains were selected on the basis of the clearance zone on solid agar media of Pikovskaya and Jensen's media containing TCP, and phosphate solubilization in Jensen's liquid culture medium containing both TCP and MRP. Mutants of the best phosphate-solubilizing (TCP 1.52 μg ml–1 MRP 0.19 μg ml–1), IAA-producing A. chroococum strain P-4, were developed and screened for P solubilization and phytohormone production. Five mutants solubilized more P (in the range of 1.5–1.7 μg/ml–1 of TCP and 0.19–0.22 μg ml–1 of MRP) than the parent strains. In vitro growth emergence studies of three wheat varieties, viz. C-306, WH-542 and HD-2009, showed better performance with phosphate-solubilizing mutants than with the parent strain.
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    Soil mineral nitrogen dynamics under bare fallow and wheat in vertisols of semi-arid Mediterranean Morocco (1999)
    Springer
    Biology and fertility of soils 28 (1999), S. 321-328 
    Details
    ISSN: 1432-0789
    Keywords: Key words Mineral nitrogen ; Morocco ; Plant available nitrogen ; Vertisol ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The evoluion of NH4 +-N and NO3 –-N was monitored during three growing seasons, 1992–1993, 1993–1994, 1994–1995 in the soil profile (0–60 or 0–90 cm) under bare fallow and wheat on a vertisol site of the Sais plateau, Morocco. The aim of this study was to relate the soil mineral N dynamics to crop N uptake and soil N transformation processes. The efficacy of the current N fertilisation rate (100 kg N ha–1) for wheat production in the region was evaluated. The high level of residual mineral N in the soil profile resulted from a low N plant uptake relative to the soil N supply and N fertilisation, and masked the effect of N fertilisation on dry matter accumulation. NH4 +-N was present in considerable amounts, suggesting a low nitrification rate under the given pedo-climatic conditions. An artefact due to the sampling procedure was encountered shortly after the application of N fertiliser. Losses through leaching and denitrification occurred after heavy rainfall, but were limited. At least part of the exchangeable NH4 +-N seemed to be barely taken up by the crop. NO3 –-N was therefore considered to be a better indicator of plant-available N than total mineral N for this type of soil. The low N fertiliser use efficiencies demonstrated clearly that the current fertilisation rate (100 kg N ha–1) for wheat production in this region is unsustainable. The maximum N uptake ranged from 40 kg N ha–1 to 180 kg N ha–1. The estimation of the seasonal production potential is considered to be the main prerequisite for the determination of the best rates and timing of N fertiliser application in this region.
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    Gram-negative bacterial flora on the root surface of wheat (Triticum aestivum) grown under different soil conditions (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 273-281 
    Details
    ISSN: 1432-0789
    Keywords: Wheat ; Triticum aestivum ; Rhizosphere ; Soil microflora ; Gram-negative bacteria ; API 20 NE ; Flavobacterium spp ; Cytophaga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We identified 161 Gram-negative bacterial strains isolated from the root surface of wheat grown under different soil conditions. The strains were divided into seven groups based on major morphological and physiological properties. Taxonomic allocation of the groups was verified by guanine+cytosine contents of DNA. Except for one group, which may be assumed to include bacteria belonging to the genera Flavobacterium and Cytophaga, the various groups were taxonomically united. The distribution of the groups changed with soil improvement. Pseudomonads predominated in unimproved soil, but Flavobacterium and Cytophaga spp. were predominant in the most improved soil. As all the strains were non-fermentative by Hugh and Leifson's test, API 20NE identification was applied. However, many strains were misidentified by this system, especially in the Flavobacterium and Cytophaga spp. group. For ecological studies, the strains were classified to species level by the API 20 NE system and by the results of a combination of guanine+cytosine (mol%) and isoprenoid quinone data. The pattern of distribution of the bacteria on the root surface of wheat varied at species level within one genus depending on soil conditions.
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    Manganese-oxidizing ability of isolates of the take-all fungus is correlated with virulence (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 272-278 
    Details
    ISSN: 1432-0789
    Keywords: Take all ; Manganese oxidation ; Virulence ; Wheat ; Gaeumannomyces graminis var. tritici ; Epidemiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two successive experiments described here show that the Mn-oxidizing ability of isolates of the take-all fungus Gaeumannomyces graminis var. tritici is positively correlated with the isolate virulence. Isolates of G. graminis var. tritici were screened for virulence on wheat in soil culture pot tests and visually scored for Mn-oxidizing capacity on agar plates. A comparison between experiments showed that the Mn-oxidizing ability of an isolate may be attenuated, as is virulence, with subculturing. Using a solution culture system, we calculated the rate of oxidation of Mn2+ by a virulent isolate, Ggt 500, as 4 nmol g-1 (dry weight hyphae) h-1. The significance of these results to the epidemiology of the take-all disease of wheat is discussed.
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    Influence of different agricultural practices (type of crop, form of N-fertilizer) on soil nitrous oxide emissions (1998)
    Springer
    Biology and fertility of soils 27 (1998), S. 299-306 
    Details
    ISSN: 1432-0789
    Keywords: Key words Nitrous oxide emissions ; Soil chamber method ; Nitrogen fertilizer types ; Wheat ; Rapeseed crop
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  N2O emissions were periodically measured using the static chamber method over a 1-year period in a cultivated field subjected to different agricultural practices including the type of N fertilizer (NH4NO3, (NH4)2SO4, CO(NH2)2 or KNO3 and the type of crop (rapeseed and winter wheat). N2O emissions exhibited the same seasonal pattern whatever the treatment, with emissions between 1.5 and 15 g N ha–1 day–1 during the autumn, 16–56 g N ha–1 day–1 in winter after a lengthy period of freezing, 0.5–70 g N ha–1 day–1 during the spring and lower emissions during the summer. The type of crop had little impact on the level of N2O emission. These emissions were a little higher under wheat during the autumn in relation to an higher soil NO3 – content, but the level of emissions was similar over a 7-month period (2163 and 2093 g N ha–1 for rape and wheat, respectively). The form of N fertilizer affected N2O emissions during the month following fertilizer application, with higher emissions in the case of NH4NO3 and (NH4)2SO4, and a different temporal pattern of emissions after CO(NH2)2 application. The proportion of applied N lost as N2O varied from 0.42% to 0.55% with the form of N applied, suggesting that controlling this agricultural factor would not be an efficient way of limiting N2O emissions under certain climatic and pedological situations.
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    Manganese-oxidizing ability of isolates of the take-all fungus is correlated with virulence (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 272-278 
    Details
    ISSN: 1432-0789
    Keywords: Key words Take all ; Manganese oxidation ; Virulence ; Wheat ; Gaeumannomyces graminis var. tritici ; Epidemiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two successive experiments described here show that the Mn-oxidizing ability of isolates of the take-all fungus Gaeumannomyces graminis var. tritici is positively correlated with the isolate virulence. Isolates of G. graminis var. tritici were screened for virulence on wheat in soil culture pot tests and visually scored for Mn-oxidizing capacity on agar plates. A comparison between experiments showed that the Mn-oxidizing abilility of an isolate may be attenuated, as is virulence, with subculturing. Using a solution culture system, we calculated the rate of oxidation of Mn2+ by a virulent isolate, Ggt 500, as 4 nmol g–1 (dry weight hyphae) h–1. The significance of these results to the epidemiology of the take-all disease of wheat is discussed.
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    Some aspects on the origin of fold-type fabrics — theory, experiments and field applications (1983)
    Springer
    International journal of earth sciences 72 (1983), S. 1167-1196 
    Details
    ISSN: 1437-3262
    Keywords: Experiment ; anisotropy ; stress ; strain ; pure shear ; simple shear ; buckling ; bending ; macroscopic fabric ; symmetry ; flexural-slip fold ; kink band ; Jura-Mountains ; Rhenish Massif (Rheinisches Schiefergebirge, Ruhr district)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract An applicable interpretation of fabrics should be based mainly on geometrical considerations in order to cover available field data. Therefore a theory on the formation of foldtype fabrics including congruent and concentric flexural-slip folds as well as kink bands in materials subjected to rhombic and different monocline strain types is derived by means of particle motion fields for homogeneous and isotropic bodies. The analysis of experimental results and their comparison with field observations largely confirms the theory and contributes to its improvement. Some trends can be established: With increasing monocline character of the strain type, the probability of concentric and congruent flexural-slip folding is reduced. It is substituted by kink band formation. While the portion of monocline strain is enlarged with depth, rhombic fold symmetry indicates, in the realm of elastic-plastic behaviour, the proximity of the surface of the earth or of a detachment surface. With gradual increase of the rock anisotropy, the development of shear faults, kink folds and, finally, congruent and concentric flexural-slip folds is favoured.
    Abstract: Résumé L'interprétation, en vue de son application, de la genèse des formes structuraux résultant de processus tectoniques doit être basée essentiellement sur des raisonnements géométriques pour qu'elle corresponde à la structure des observations faites sur le terrain. Pour cette raison, une théorie de la formation des formes structuraux d'aspect plissé, y compris des plis semblables ou isopaques à glissement banc sur banc ainsi que des knicks, est développée à partir d'une figuration générale des mouvements des particules dans les corps homogènes et isotropes soumis à des déformations à symétrie orthorhombique ou monoclinique. L'analyse des résultats expérimentaux et des comparaisons avec des observations sur le terrain confirment largement la théorie et contribuent à son perfectionnement. Quelques tendances se dessinent: avec l'accroissement du caractère monoclinique de la déformation s'accroît aussi la probabilité de la formation des knicks plutôt que des plis à glissements banc sur banc, concentriques et congruents. Tandis que la déformation monoclinique prend une part plus importante avec la profondeur, la symétrie orthorhombique des plis en régime de déformation élastoplastique indique la proximité de la surface de la Terre ou d'une surface de décollement. Avec l'augmentation de l'anisotropie des roches, la formation de cassures de cisaillement, de knicks et enfin de plis semblables et isopaques à glissement banc sur banc est favorisée.
    Notes: Zusammenfassung Eine anwendungsbezogene Deutung der Gefügegenese muß in erster Linie auf geometrischen Überlegungen beruhen, damit sie auf Geländedaten übertragen werden kann. Ausgehend von Partikelbewegungsfeldern, die für homogene und isotrope Körper gelten, wird eine Theorie der Genese faltenförmiger Gefüge entwickelt, die konzentrische und kongruente Biegegleitfalten und Knickzonen bei rhombischen und monoklinen Deformationstypen erfaßt. Die Ergebnisse von Experimenten und der Vergleich mit Geländebefunden bestätigen weitgehend die Theorie und tragen zu ihrer Weiterentwicklung bei. Einige Trends zeichnen sich ab: Mit steigender Monoklinität des Deformationstyps nimmt die Wahrscheinlichkeit der Bildung von Knickzonen auf Kosten von konzentrischen und kongruenten Biegegleitfalten zu. Während der Anteil monokliner Deformation zur Tiefe hin größer wird, zeigt eine rhombische Symmetrie der Falten im elastisch-plastischen Bereich die Nähe der Erdoberfläche oder einer Abscherungsfläche an. Bei zunehmender Anisotropie werden zunächst bevorzugt Scherbrüche, dann Knickzonen und schließlich kongruente und konzentrische Biegegleitfalten gebildet.
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    Some aspects on the origin of fold-type fabrics — theory, experiments and field applications (1983)
    Springer
    International journal of earth sciences 72 (1983), S. 421-450 
    Details
    ISSN: 1437-3262
    Keywords: Experiment ; anisotropy ; stress ; strain ; pure shear ; simple shear ; buckling ; bending ; macroscopic fabric ; symmetry ; flexural-slip fold ; kink band ; Jura-Mountains ; Rhenish Massif (Rheinisches Schiefergebirge, Ruhr district)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Abstract An applicable interpretation of fabrics should be based mainly on geometrical considerations in order to cover available field data. Therefore a theory on the formation of foldtype fabrics including congruent and concentric flexural-slip folds as well as kink bands in materials subjected to rhombic and different monocline strain types is derived by means of particle motion fields for homogeneous and isotropic bodies. The analysis of experimental results and their comparison with field observations largely confirms the theory and contributes to its improvement. Some trends can be established: With increasing monocline character of the strain type, the probability of concentric and congruent flexural-slip folding is reduced. It is substituted by kink band formation. While the portion of monocline strain is enlarged with depth, rhombic fold symmetry indicates, in the realm of elastic-plastic behaviour, the proximity of the surface of the earth or of a detachment surface. With gradual increase of the rock anisotropy, the development of shear faults, kink folds and, finally, congruent and concentric flexural-slip folds is favoured.
    Abstract: Résumé L'interprétation, en vue de son application, de la genèse des formes structuraux résultant de processus tectoniques doit être basée essentiellement sur des raisonnements géométriques pour qu'elle corresponde à la structure des observations faites sur le terrain. Pour cette raison, une théorie de la formation des formes structuraux d'aspect plissé, y compris des plis semblables ou isopaques à glissement banc sur banc ainsi que des knicks, est développée à partir d'une figuration générale des mouvements des particules dans les corps homogènes et isotropes soumis à des déformations à symétrie orthorhombique ou monoclinique. L'analyse des résultats expérimentaux et des comparaisons avec des observations sur le terrain confirment largement la théorie et contribuent à son perfectionnement. Quelques tendances se dessinent: avec l'accroissement du caractère monoclinique de la déformation s'accroît aussi la probabilité de la formation des knicks plutôt que des plis à glissements banc sur banc, concentriques et congruents. Tandis que la déformation monoclinique prend une part plus importante avec la profondeur, la symétrie orthorhombique des plis en régime de déformation élastoplastique indique la proximité de la surface de la Terre ou d'une surface de décollement. Avec l'augmentation de l'anisotropie des roches, la formation de cassures de cisaillement, de knicks et enfin de plis semblables et isopaques à glissement banc sur banc est favorisée.
    Notes: Zusammenfassung Eine anwendungsbezogene Deutung der Gefügegenese muß in erster Linie auf geometrischen Überlegungen beruhen, damit sie auf Geländedaten übertragen werden kann. Ausgehend von Partikelbewegungsfeldern, die für homogene und isotrope Körper gelten, wird eine Theorie der Genese faltenförmiger Gefüge entwickelt, die konzentrische und kongruente Biegegleitfalten und Knickzonen bei rhombischen und monoklinen Deformationstypen erfaßt. Die Ergebnisse von Experimenten und der Vergleich mit Geländebefunden bestätigen weitgehend die Theorie und tragen zu ihrer Weiterentwicklung bei. Einige Trends zeichnen sich ab: Mit steigender Monoklinität des Deformationstyps nimmt die Wahrscheinlichkeit der Bildung von Knickzonen auf Kosten von konzentrischen und kongruenten Biegegleitfalten zu. Während der Anteil monokliner Deformation zur Tiefe hin größer wird, zeigt eine rhombische Symmetrie der Falten im elastisch-plastischen Bereich die Nähe der Erdoberfläche oder einer Abscherungsfläche an. Bei zunehmender Anisotropie werden zunächst bevorzugt Scherbrüche, dann Knickzonen und schließlich kongruente und konzentrische Biegegleitfalten gebildet.
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    The Effect of Habitat Changes on the Endangered Ground Beetle Carabus Nitens (Coleoptera: Carabidae) (1999)
    Springer
    Journal of insect conservation 3 (1999), S. 107-116 
    Details
    ISSN: 1572-9753
    Keywords: Coleoptera ; Carabus nitens ; heathlands ; habitat fragmentation ; age structure ; allozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract Carabus nitens, one of the most endangered ground beetles in Central Europe, was investigated with pitfall traps at 30 sampling sites in 17 heath fragments of the largest German heath landscape under nature conservation (nature reserve 'Lüneburger Heide'). The preference for damp Erica heaths and dry Calluna heaths in the building phase was thereby evident. Calluna heaths in the mature and degenerate phase, with and without extensive coverage by Avenella flexuosa, are either not inhabited or are avoided. The results of ovary dissections indicate that the populations in two successive spring seasons consisted mainly of animals which had already reproduced and were therefore older than one and a half years. Allozyme electrophoreses revealed variation for three of the nine investigated enzyme loci, and large differences in the allele frequency at one of these loci indicated genetic drift and fluctuations in the size of local populations. According to these results and statements in the literature, the loss of heathland areas and habitat quality are both responsible for the decline of the species. Suitable measures for preserving the species are (1) restoration of building phases of the Calluna heaths and (2) interconnection of at least the smaller heath fragments. Finally, recommendations are given for reintroductions.
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    URL: http://dx.doi.org/10.1023/A:1009673721288
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    Distribution, Ecology and Population Dynamics of the American Burying Beetle [Nicrophorus Americanus Olivier (Coleoptera, Silphidae)] in South-central Nebraska, USA (1999)
    Springer
    Journal of insect conservation 3 (1999), S. 171-181 
    Details
    ISSN: 1572-9753
    Keywords: Coleoptera ; endangered ; pit fall trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract The endangered American burying beetle, Nicrophorus americanus Olivier, was previously widespread throughout eastern North America. In the past century numbers of this beetle have drastically declined and currently remnant populations are known from only six states despite intensive surveying efforts conducted for the last nine years. Efforts aimed at discovering and managing remnant populations have been generally limited by a lack of knowledge concerning N. americanus biology. We used baited pitfall traps to define the range of the Gothenburg, Nebraska population of N. americanus. Using mark-recapture techniques, we estimate that the annual Gothenburg population consists of more than one thousand individuals, meeting the recovery plan criterion to become the third breeding population in the Midwest region. Beyond estimates of population size and range, we present novel data on seasonal and daily activity, sex ratio, age-grading and foraging distances. In 1995 and 1996, the Nebraska population was univoltine and female biased, with over-wintering mature beetles emerging in early June and teneral beetles emerging in August. Nocturnal activity was highest in the third and fourth hours following sunset but was not strongly correlated with temperature. During foraging, beetles travel up to six kilometers, but the majority of our recaptures occurred at distances of less than 0.5 km, suggesting that distances between traps be increased to ensure independence of sampling units. This information will allow future work on captive breeding, re-introduction and genetic studies.
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    Paleolimnological analysis of Ullswater using testate amoebae (1995)
    Springer
    Journal of paleolimnology 13 (1995), S. 51-63 
    Details
    ISSN: 1573-0417
    Keywords: acidification ; England ; Holocene ; Lake District ; paleolimnology ; testate amoebae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Tests of testate amoebae extracted from samples of bottom sediments from 33 tarns in the English Lake District reveal a relationship between their distribution and physical-chemical parameters of the tarn waters.Nebela and several species ofDifflugia appear to prefer more acidic conditions, i.e., pH less than 6.2, while others such asCentropyxis, Lesquereusia and some species ofCyclopyxis andDifflugia are more common in lakes with pH's above that value. Using these data, and inferring rates of sedimentation from the densities of tests found in a 6-m core, a paleolimnological history for the past 11 000 years is presented for Ullswater (English Lake District). The record of testate amoebae, beginning shortly after deglaciation, depicts an uneven increase in acidity and a history of episodes of rapid and slow deposition that correlate reasonably well with paleoclimatological changes and anthropogenic alterations in the catchment.
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    Late holocene paleoclimatic and paleobiologic records from sediments of Devils Lake, North Dakota (1995)
    Springer
    Journal of paleolimnology 13 (1995), S. 193-207 
    Details
    ISSN: 1573-0417
    Keywords: paleolimnology ; lake levels ; biogenic silica ; organic matter ; isotopes ; North Dakota
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract An 84 cm sediment core collected from the center of Devils Lake, North Dakota, was analyzed at 1-cm intervals for,210Pb,137Cs, sediment conductivity, the concentrations of, biogenic silica, total organic carbon, carbon to nitrogen ratio, and the carbon and nitrogen isotopic composition of the organic fraction. Variations in210Pb activities in the upper 20 centimeters indicate that sediment accumulations rates in Devils Lake are not constant, and that accumulation rates were highest during periods of high lake level. The mean sedimentation accumulation rate was calculated as 0.24 cm−1 yr. The137Cs profile is characterized by near-surface maximum concentrations, possibly the result of redistribution of137Cs during salinity excursions. Biogenic silica is strongly correlated to lake level in Devils Lake. Periods of low lake level (characterized by high sediment conductivity) correspond to low biogenic silica concentrations. The trends in biogenic silica are attributed to variations in diatom productivity in the lake and to variations in sediment accumulation rates. Based on biogenic silica content and the composition of organic matter in the sediment (total organic carbon, carbon:nitrogen ratio and the δ13C and δ15N composition of total organic matter), paleobiologic conditions of Devils Lake during low lake stands were characterized by, (1) decreased primary productivity, (2) decreased input of detrital organic matter, and (3) increased nitrogen availability. During the 350 years of sediment accumulation represented by the 84-cm sediment core Devils Lake has experienced two periods of sustained high lake level; one between about 130 and 170 years ago (1820 to 1860 A.D.) and the second between 270 and 310 years ago (1680 to 1720 A.D.). Devils Lake experienced a period of intense drying about 260 years ago (1720 A.D.).
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    Diatom succession in an urban reservoir system (1996)
    Springer
    Journal of paleolimnology 15 (1996), S. 237-243 
    Details
    ISSN: 1573-0417
    Keywords: reservoir ; diatom ; core ; sediments ; hydrology ; paleolimnology ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A 43 cm by 5 cm diameter sediment core sample was obtained from Ford Lake reservoir in Washtenaw County, Michigan, and sectioned at 1 cm intervals. The purpose of this study was to determine whether diatom communities in this reservoir have undergone quantifiable changes in abundance and composition since its creation. Thirty-one cm of this core appeared to represent material deposited since the creation of the reservoir based on changes in diatom abundance, the physical composition of the sediment and the change in biogenic SiO2 concentration. Fortyseven species of diatoms were identified total concentrations of diatom remains varied from 1×104 g-1 to 1×107 g-1. Prior to the establishment of the reservoir, the diatom flora was dominated by benthic taxa. Benthic diatoms were numerous throughout the entire core, but eutrophic taxa (e.g., Aulacoseira italica, Aulacoseira granulata, Stephanodiscus niagarae, Fragilaria crotonensis) dominated much of the core after the reservoir's creation. Total diatom density increased about tenfold in the about the first 10–15 years after the reservoir's creation before declining markedly.
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    Siliceous microfossil distribution in the surficial sediments of Lake Baikal (1995)
    Springer
    Journal of paleolimnology 14 (1995), S. 69-82 
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    ISSN: 1573-0417
    Keywords: Russia ; Lake Baikal ; paleolimnology ; diatoms ; stomatocysts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Examination of surficial sediments at 16 stations shows minor, but consistent differences in the numbers and kinds of siliceous microfossils deposited in different regions of Lake Baikal. There is a general north-south decreasing trend in total microfossil abundance on a weight basis. Endemic plankton diatom species are the most abundant component of assemblages at all stations. Chrysophyte cysts are present at all stations, but most forms are more abundant at northern stations. Non-endemic plankton diatom species are most abundant at southern stations. Small numbers of benthic diatoms and sponge spicules are found in all samples. Although low numbers are present in offshore sediments, the benthic diatom flora is very diverse. Principal components analysis confirms primary north-south abundance trends and suggests further differentiation by station location and depth.
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    URL: http://dx.doi.org/10.1007/BF00682594
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    Temporal variations of fossil Cladocera in the sediments of Lake Orta (N. Italy) over the last 400 years (1995)
    Springer
    Journal of paleolimnology 14 (1995), S. 113-122 
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    ISSN: 1573-0417
    Keywords: Cladocera remains ; paleolimnology ; climate ; pollution ; human impact ; Italy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract We use Cladocera remains in the sediments to reconstruct the longterm history of Lake Orta, a lake which experienced severe pollution from copper and ammonium sulphate, and started to recover during the last 15 years. Both human and natural impacts were detected over almost 400 years. Pollution was manifested by a dramatic decrease in the number of remains, in the planktonic/littoral (P/L) ratio, and in chydorid species diversity. Most species, even those most tolerant to stress, disappeared. The recolonization of biota was initially sustained by one species of chydorid,Chydorus sphaericus, which had a three-fold increase at the beginning of the 1980s, when studies on plankton recorded the development of a pelagic population. This fact, and the appearance in the sediments ofAlona quadrangularis, attest to the development of filamentous algae which was reported in studies on the plankton. The colonization of the lake by pelagic species came only in the last twelve years and was manifested also as a stabilization of the P/L ratio. Two other periods of disturbance were detected in the sediments: the first, at the end of the 19th century, was related to the introduction of exotic fish species; the second occurred during the second half of the 17th century. This event probably cannot be ascribed to human impact, but may be related to a decrease in temperature in that period (the Maunder Minimum).
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    Late Holocene lake-level and lake development signals in Lower Herring Lake, Michigan (1996)
    Springer
    Journal of paleolimnology 15 (1996), S. 19-45 
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    ISSN: 1573-0417
    Keywords: diatoms ; grain-size analysis ; lake-level changes ; Lake Michigan ; paleolimnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Paleolimnological investigations of a marginal lake in the Lake Michigan basin revealed signals of long-term lake-level changes primarily controlled by climatic forces. Multiple analyses identified concurrent signals in sediment chemistry, grain size, and the microfossil record. Coarse-grained sediments, benthic diatoms, and nutrient response species increased as lake levels rose or fell. Finer sediments and higher percentages of taxa associated with stable thermocline conditions occurred during high-lake periods. Sedimentary evidence revealed corresponding strong high-lake signals c. 2500–2200, 1800–1500, 1170–730, and 500–280 BP. Low-lake periods occurred c. 1500–1170 and 700–500 B.P. An additional signal of lake-level decline was apparent beginning c. 280 BP but was interrupted by anthropogenic effects. Evidence of extreme low-lake levels (c. 1400–1300 BP), and signals for a medieval warming period (1030–910 BP) and the Maunder minimum (370–325 BP) indicate occurrence of short-lived dry climatic conditions.
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    URL: http://dx.doi.org/10.1007/BF00176988
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    A multi-proxy study of Holocene environmental change in the Maya Lowlands of Peten, Guatemala (1998)
    Springer
    Journal of paleolimnology 19 (1998), S. 139-159 
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    ISSN: 1573-0417
    Keywords: geochemistry ; Guatemala ; Holocene ; lakesediment ; Maya ; magnetic susceptibility ; paleolimnology ; pollen ; stable isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract We used multiple variables in a sediment core from Lake Peten-Itza, Peten, Guatemala, to infer Holocene climate change and human influence on the regional environment. Multiple proxies including pollen, stable isotope geochemistry, elemental composition, and magnetic susceptibility in samples from the same core allow differentiation of natural versus anthropogenic environmental changes. Core chronology is based on AMS 14C measurement of terrestrial wood and charcoal and thus avoids the vagaries of hard-water-lake error. During the earliest Holocene, prior to ∼9000 14C yr BP, the coring site was not covered by water and all proxies suggest that climatic conditions were relatively dry. Water covered the coring site by ∼9000 14C yr BP, coinciding with filling of other lakes in Peten and farther north on the Yucatan Peninsula. During the early Holocene (∼9000 to ∼6800 14C yr BP), pollen data suggest moist conditions, but high δ 18O values are indicative of relatively high E/P. This apparent discrepancy may be due to a greater fractional loss of the lake's water budget to evaporation during the early stages of lake filling. Nonetheless, conditions were moist enough to support semi-deciduous lowland forest. Decrease in δ 18O values and associated change in ostracod species at ∼6800 14C yr BP suggest a transition to even moister conditions. Decline in lowland forest taxa beginning ∼5780 14C yr BP may indicate early human disturbance. By ∼2800 14C yr BP, Maya impact on the environment is documented by accelerated forest clearance and associated soil erosion. Multiple proxies indicate forest recovery and soil stabilization beginning ∼1100 to 1000 14C yr BP, following the collapse of Classic Maya civilization.
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    URL: http://dx.doi.org/10.1023/A:1007968508262
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    A preliminary investigation of siliceous microfossil succession in late Quaternary sediments from Lake Baikal, Siberia (1997)
    Springer
    Journal of paleolimnology 18 (1997), S. 189-206 
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    ISSN: 1573-0417
    Keywords: Lake Baikal ; Russia ; paleolimnology ; diatoms ; chrysophyte cysts ; climate change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Siliceous microfossil assemblage succession was analyzed in a 100 m sediment core from Lake Baikal, Siberia. The core was recovered from the lake's central basin at a water depth of 365 m. Microfossil abundance varied greatly within the intervals sampled, ranging from samples devoid of siliceous microfossils to samples with up to 3.49 × 1011 microfossils g-1 sediment. Fluctuations in abundance appear to reflect trends in the marine δ18O record, with peak microfossil levels generally representing climate optima. Microfossil taxa present in sampled intervals changed considerably with core depth. Within each sample a small number of endemic diatom species dominated the assemblage. Changes in dominant endemic taxa between sampled intervals ranged from extirpation of some taxa, to shifts in quantitative abundance. Differences in microfossil composition and the association of variations in abundance with climate fluctuations suggest rapid speciation in response to major climatic excursions.
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    URL: http://dx.doi.org/10.1023/A:1007924310688
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    On diatom concentrations in lake sediments: results from an inter-laboratory comparison and other tests performed on a uniform sample (1997)
    Springer
    Journal of paleolimnology 18 (1997), S. 261-268 
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    ISSN: 1573-0417
    Keywords: diatoms ; microfossil concentrations ; methods ; paleolimnology ; West Okoboji Lake ; Iowa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The diatom concentration of a uniform lake sediment sample was estimated in 15 laboratories. Whilst 21 of 35 estimates were between 13 and 19 × 107 valves g-1, values ranged from 8.2 × 106 to 2.0 × 109 valves g-1. However, counts from replicate sediment digestions, replicate slide preparations from a single digested slurry, and multiple counts from an individual slide all yielded internally consistent results, with acceptably low coefficients of variation (±4.5–6.3%). Without greater efforts towards harmonization, for example by calibrating techniques to a standard of known concentration, reported diatom concentration values, as well as derived data such as diatom accumulation rates, are not directly comparable between most laboratories. This sharply contrasts the strong reproducibility of diatom relative frequency data. A calibration exercise, using the Eucalyptus pollen spike technique to estimate a known concentration of Lycopodium spores, demonstrates that this method performs best when approximately equal proportions of microfossils and introduced markers are counted.
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    URL: http://dx.doi.org/10.1023/A:1007937300347
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    A summary of past and recent plankton of Lake Winnipeg, Canada using algal fossil remains (1998)
    Springer
    Journal of paleolimnology 19 (1998), S. 297-307 
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    ISSN: 1573-0417
    Keywords: eutrophication ; algae ; bluegreen akinetes ; non-siliceousmicro fossils ; diatoms ; paleolimnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Although the phytoplankton and protozoan assemblages of Lake Winnipeg are quite variable both, spatial and temporally, knowledge of their current distribution and ecology enables them to be used as indicators providing unique information concerning past and recent ecosystem conditions. Many of the main taxa have been similar throughout history although there have been dramatic changes in their abundance. Lake Winnipeg is currently very responsive to the climatic conditions in its drainage basin and it appears, historically, to have been a diatom-bluegreen algal lake with Tintinnids and thecate amoeba forming significant components of the protozoan community. A wide variety of microfossil remains have been used to infer past conditions in this large prairie lake. Microfossils reported from the long core 103 (8 m) taken from the north basin of LakeWinnipeg and short core Namao 7a taken from the south basin of the lake in August 1994 indicate that the lake has experienced several changes over its history. Diatom assemblages, low throughout the core 103 below 50 cm, except for a peak around 300–400 cm are virtually absent below 690–800 cm (Lake Agassiz). Stephanodiscus and Aulacoseira are the two major pelagic diatom genera represented throughout the lake's history. Species changes occur near the top of the core indicate increased anthropogenic eutrophication. Shallow water littoral taxa were never abundant at either coring sites. The presence of planktic cyanoprokaryote (cyanophyte, cyanobacteria, bluegreen algae) remains (akinetes) from 600 cm depth and the progressive increase in abundance from 400 cm to through the top 100 cm of the core indicates increasing phosphorus levels, warming summer temperatures and increasing summer nitrogen limitation in the lake. Nitrogen fixing bluegreens (especially Anabaena and Aphanizomenon akinetes) and the diatoms (Aulacoseira ambigua, A. granulata, A. islandica, S. binderanus, and S. niagarae) were abundant in the upper sediments and changes after 100 cm can be interpreted as the effects of human impact. These taxa indicative of increase eutrophication, in addition to S. agassizensis, Melosira varians and Cyclostephanos dubius, are representative of present day plankton. The short core Namao 7a was dated by Pb210 and the fossil remains also show a rise in the Aulacoseira (particularly A. granulata and A. ambigua) and bluegreen akinetes in the last 40 years as was seen in the upper sediments of the 103 core. There was an interesting peak in chrysophyte cysts during the 1930's which corresponds nicely with climatic conditions during this period. The fires accompaning the hot dry period in the mid 70's can be seen in the dramatic rise in charcoal during this period. Multiple types of micro fossils remains provides several useful tools for interpreting past lacustrine conditions.
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    URL: http://dx.doi.org/10.1023/A:1007990217568
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    A diatom-conductivity transfer function for Spanish salt lakes (1998)
    Springer
    Journal of paleolimnology 19 (1998), S. 399-416 
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    ISSN: 1573-0417
    Keywords: saline lakes ; paleolimnology ; paleoclimate ; diatoms ; transfer functions ; Spain ; CCA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Diatom-salinity transfer functions for interpretation of palaeosalinity and palaeoclimate change have been developed successfully for parts of North America and North and East Africa, but there is a need for data-sets in other saline lake regions of the world. A data-set of 74 modern diatom samples and associated water chemistry data is described from Spain. The influence of conductivity and other environmental variables on diatom distribution is explored using canonical correspondence analysis (CCA) and partial CCAs. A transfer function is derived for conductivity (70 samples) whose apparent predictive ability is high (apparent r2 = 0.91). Performance under jackknifing is poor due to the heterogeneous nature of the data-set and poor coverage of the freshwater end of the salinity gradient. There is a lack of suitable low-salinity sites in Spain, and the accuracy of estimated salinity optima and tolerance ranges may be improved by merging this data-set with those of other regions. The Spanish transfer function has strong affinities with the African data-set and contributes important ecological data for diatom taxa which are absent or poorly represented in the modern flora of African lakes, and for which, in fossil material, there were previously no good modern analogues.
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    URL: http://dx.doi.org/10.1023/A:1007934627134
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    Paleolimnological significance of spinose and non-spinose morphs of Pyrgophorus hibbardi (Leonard and Franzen, 1944) (1998)
    Springer
    Journal of paleolimnology 20 (1998), S. 99-102 
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    ISSN: 1573-0417
    Keywords: Pliocene ; Oklahoma ; Pyrgophorus hibbardi ; paleolimnology ; stable isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The basal portion of the Ogallala Formation (=‘Laverne Formation’) (Lower Pliocene) Beaver County, Oklahoma, contains an interesting assemblage of non-marine fossil molluscs that include both spinose and non-spinose forms of the aquatic gastropod species Pyrgophorus hibbardi. The origin and paleolimnological significance of the spinose morph has been a source of much conjecture that has influenced environmental reconstructions of this assemblage. In one hypothesis the spinose forms of P. hibbardi are assumed to be associated with brackish water conditions by analogy with some populations of a related hydrobiid Potamopyrgus jenkinsi. To test the hypothesis that the spinose forms lived under different water conditions than the non-spinose morphs, we analyzed 10 specimens each of the two varieties for stable oxygen and carbon isotope ratios in the shell aragonite. The mean isotope ratios for the smooth and spinose morphs show no significant difference (oxygen: t = 0.28, df = 18, P (T ≤ t) 0.78 n.s.; carbon: t = 0.96, df = 18, P (T ≤ t) 0.35 n.s). We conclude that the lack of a statistically significant difference between the means of the oxygen and carbon isotope values for the smooth and spinose morphs suggests that the two forms lived in waters having similar isotope signatures. The considerable range in oxygen isotope values recorded by both morphs of P. hibbardi, including values as high as 5–6‰, suggest that both morphs were associated with waters which were periodically evaporatively enriched in 18O.
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    URL: http://dx.doi.org/10.1023/A:1007918626424
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    Late Quaternary diatom response to vegetation and climate change in a subalpine lake in Banff National Park, Alberta (1998)
    Springer
    Journal of paleolimnology 20 (1998), S. 253-265 
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    ISSN: 1573-0417
    Keywords: Late Quaternary ; diatoms ; climate change ; vegetation change ; shallow ; subalpine ; Crowfoot Lake ; Alberta ; paleolimnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The late Quaternary diatom record from subalpine Crowfoot Lake, Banff National Park, Alberta (lat. 51° 61′N; long. 116° 31′W) has been analyzed. Results are related to independently inferred vegetation and climate changes. No diatoms were found in the basal diamict that predates 11330 14C yr BP. Very few occur until ca. 10 10014 C yr BP probably due to the short time between de-glaciation and an advance of the Crowfoot Glacier during the ‘Younger Dryas Chron’. Initial pioneering species were characteristic of alkaline water and calcareous organic sediments. They appeared as sediments became organic and laminated suggesting increasing water clarity, and as the Pinus-dominated forest expanded and the climate warmed. After ca. 9060 14C yr BP diatom numbers increased rapidly, reaching a maximum prior to the Mazama tephra; they remained high until ca. 3500 14C yr BP. The period between ca. 9060 and 3500 14C yr saw timberline elevation increase and the dominance of xerophytic taxa. These are consistent with early to mid-Holocene warmth and aridity. Diatom productivity reflects the warm climate and presumably longer ice-free season, a stable catchment and transparent water. Decreases in diatom productivity coincide with a vegetation change with reduction of xerophytic taxa and the appearance of a closed Picea-Abies forest, hence a cooler, wetter climate at ca. 4100 to 3500 14C yr BP. The diatom numbers during the Neoglacial were of the same magnitude as prior to ca. 9060 14C yr BP. Small species of Fragilaria (overwhelmingly Fragilaria construens v. venter) became extremely dominant during the period of high diatom productivity, and remained so thereafter. Recovery of the lake appears to have been rapid after deposition of the Mazama tephra. Maximum occurrence of Cyclotella radiosa occurred ca. 8000 14C yr BP during the warm early Holocene and may reflect this warmer climate, a longer ice-free season than presently, perhaps less turbid water, or it may reflect a subtly higher nutrient status of the lake water. The diatom record of Crowfoot Lake has responded with sensitivity, particularly in terms of productivity, to the Holocene vegetation and climate changes.
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    URL: http://dx.doi.org/10.1023/A:1007978730349
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    Reconstruction of Holocene paleoenvironments in the endorheic basin of Laguna de Gallocanta, Central Spain by investigation of mineralogical and geochemical characters from lacustrine sediments (1998)
    Springer
    Journal of paleolimnology 20 (1998), S. 217-234 
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    ISSN: 1573-0417
    Keywords: bulk geochemistry ; Holocene ; lacustrine sediments ; paleoenvironments ; paleolimnology ; statistical methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The paper involves detailed geochemical and mineralogical analysis of lacustrine sediments from a 95 cm core profile collected in the closed lake basin of the Laguna de Gallocanta, central Iberian Chain. The environmental and depositional changes are confirmed by: (1) variations in concentrations of SiO2, CaO and P2O5, (2) Fe2O3:MnO-ratios, (3) ς(CaO,MgO):SiO2-ratio, (4) statistical relationship of silica and phosphate content to metallic oxide content, (5) the Mg:Ca-ratio of protodolomites in relation to the position of the diffraction angle of dolomite's major diffraction peak (dol100, and (6) changes in mineralogical composition. Three sedimentary units were identifyed and characterized by their mineralogical and geochemical composition. The deposition of the underlying strata (section 1) occurred under sub-arid conditions. The environment changed to sub-humid conditions during deposition of the sediments in section 2 (post Middle Ages). Increasing aridity influenced the accumulation of the upper sediments (section 3). It is also proven that mineralogical analyses of lacustrine sediments allows mostly conclusions on the limnic environments during deposition. In contrast to this, geochemical features of lacustrine sediments indicate weathering and soil forming processes during deposition and the overall geomorphological system.
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    URL: http://dx.doi.org/10.1023/A:1007924000636
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    High-resolution paleoecological analysis of recent disturbance in a southern Chilean Nothofagus forest (1998)
    Springer
    Journal of paleolimnology 20 (1998), S. 235-252 
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    ISSN: 1573-0417
    Keywords: fire ; disturbance ; paleoecology ; paleolimnology ; pollen ; chrystophytes ; charcoal ; Chile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A 1600 year paleoecological record of environmental change is developed from a small lake in the Nothofagus forest of southern Chile (45.5°S, 72°W). High resolution fossil pollen, charcoal, sedimentological, and chrysophycean stomatocyst analyses are used to investigate the impacts of natural and anthropogenic disturbances on terrestrial and lacustrine environments. Chronological control is based on a combination of 210Pb and 14C dating. Temporal resolution during the past 150–200 yr is ca. 8 yr/sample. The macroscopic charcoal record correlates very closely with historical and dendroecological records of 20th century anthropogenic burning in this region. The chrysophyte stratigraphy indicates that this burning had immediate impacts on the lake itself, while the pollen record provides evidence for a succession of vegetation changes lagging slightly behind the disturbance. These palynological changes are very similar to the pollen signal of European disturbance in northeastern North America. Pre-European shifts in chrysophyte assemblages may be due to the influence of earthquake activity on the lake, though there is no corroborative evidence in the pollen or charcoal records. This study demonstrates that high resolution paleoecological methods can be used to help bridge the temporal gap between traditional ecological and paleoecological studies of environmental change in the temperate forests of southern South America.
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    URL: http://dx.doi.org/10.1023/A:1007950905200
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    Sediment focusing and210Pb dating: a new approach (1995)
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    Journal of paleolimnology 13 (1995), S. 107-118 
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    ISSN: 1573-0417
    Keywords: 210Pb ; sediments ; cores ; paleolimnology ; lakes ; sediment focusing ; sampling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract In this paper we test the utility of the mud deposition boundary depth (mud DBD) theory (Rowanet al. 1992) as a means of maximizing sampling efficiency in paleolimnological investigations, particularly those that apply to210Pb dating. The mud DBD is defined by the relationship between near bottom wave velocity and particle threshold velocity, with wave and particle threshold theory simplified to terms of exposure and depth. Mud DBD theory can be used to define the depositional zone in lakes, and within the depositional zone defined by the mud DBD: 1) there is a high probability of obtaining a representative core, 2) variation in mass sediment accumulation rate (MSAR) is not correlated with water depth, and 3) variation in MSAR is considerably reduced from the whole lake average. This suggests that mud DBD theory can account for the effects of sediment focusing, and that the mud DBD defined depositional zone is the zone to which fine-grained sediments are focused. Finally, we have shown that to optimize sampling effort, 5 to 10 cores within the depositional zone are necessary for a reasonably precise estimate of the mean mass sediment accumulation rate. In addition, the use of mud DBD theory prior to sampling can dramatically reduce the cost associated with analyzing large numbers of cores for210Pb.
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    URL: http://dx.doi.org/10.1007/BF00678101
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    An expanded weighted-averaging model for inferring past total phosphorus concentrations from diatom assemblages in eutrophic British Columbia (Canada) lakes (1995)
    Springer
    Journal of paleolimnology 14 (1995), S. 49-67 
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    ISSN: 1573-0417
    Keywords: diatoms ; eutrophication ; lake management ; paleolimnology ; British Columbia ; lakes ; phosphorus ; training sets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Eighteen lakes were added to a published training set of 46 British Columbia (BC) lakes in order to expand the original range of total phosphorus (TP) concentrations. Canonical correspondence analysis (CCA) was used to analyze the relationship between diatom assemblages and environmental variables. Specific conductivity and [TP] each explained significant (P≤0.05) directions of variance in the distribution of the diatoms. The relationship between diatom assemblages and [TP] was sufficiently strong to warrant the development of a weighted-averaging (WA) regression and calibration model that can be used to infer past trophic status from fossil diatom assemblages. The relationship between observed and inferred [TP] was not improved by the addition of more eutrophic lakes, however the [TP] range and the number of taxa used in the transfer function are now superior to the original model. Diatom species assemblages changed very little in lakes with TP concentrations greater than 85 µg 1−1, so we document the development of a model containing lakes with TP≤85 µg 1−1. The updated model uses 59 training lakes and covers a range of species optima from 6 to 41.9 µg 1−1 TP, and a total of 150 diatom taxa. The updated inference model provided a more realistic reconstruction of the anthropogenic history of a highly eutrophic BC lake. The model can now be used to infer past nutrient conditions in other BC lakes in order to assess changes in trophic status.
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    URL: http://dx.doi.org/10.1007/BF00682593
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    An assessment of recent trophic changes in Windermere South Basin (England) based on diatom remains and fossil pigments (1995)
    Springer
    Journal of paleolimnology 14 (1995), S. 151-163 
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    ISSN: 1573-0417
    Keywords: chlorophyll ; diatoms ; myxoxanthophyll ; oscillaxanthin ; sediments ; eutrophication ; England ; paleolimnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Cyanobacterial carotenoids and diatom remains have been analyzed in recent sediments from the Windermere South Basin (WSB) to study the trophic evolution experienced by the lake. Dates in the top 30 cm were specifically established through radionuclide (210Pb and137Cs) analyses. Diatom stratigraphy shows dominance of the centric diatomsCyclotella comensis andC. radiosa and several benthic taxa in the early postglacial. This indicates oligotrophy in the WSB during that period. This assemblage was replaced by another dominated by the diatomAsterionella formosa in the 1870's, as has been established from the210Pb dating. From that date onwards, the lake underwent a progression towards eutrophy, indicated by the progressive increase inAulacoseira subarctica (c. 1930's),Fragilaria crotonensis (c. 1943), and more recently, of the centricsStephanodiscus parvus (c. 1971) andCyclotella meneghiniana (1988). Carotenoid stratigraphy reveals the differences between different sections of the core. Oscillaxanthin and myxoxanthophyll had very low records in the early and medium parts of the core, but increased fromc. 1950's, showing peaks atc. 1967, 1979 and 1987. Some of these peaks indicated a differential abundance ofOscillatoria, and are matched to those observed directly during the ongoing monitoring of the phytoplankton of the lake. The coincidence between the historic appearance of diatoms associated with nutrient-rich waters and the enhanced carotenoid occurrence suggest a common response to phosphorus enrichment, and that the progressive change towards eutrophy has been accentuated during the last twenty-five years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00735479
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  • 95
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    Stratification patterns in Taconite Inlet, Ellesmere Island, N.W.T. (1996)
    Springer
    Journal of paleolimnology 16 (1996), S. 205-215 
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    ISSN: 1573-0417
    Keywords: fjords ; stratification ; meromixis ; paleolimnology ; Arctic ; Ellesmere Island
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The middle arm of Taconite Inlet shows many features in common with high-Arctic fjords and coastal meromictic lakes. The surface mixed layer is fresh, and a relatively constant 5.5 m deep, indicating a layer of ice of approximately the same thickness blocks communication with the Arctic Ocean. Below the primary halocline to a depth of 85 m, at least partial communication with the Arctic Ocean exists as indicated by the oxygen, salinity and thermal structures. A sill is probably found between 40 and 85 m depth, reducing circulation below it and contributing to the oxycline. For a long but undetermined period prior to the separation of lakes C1, and C2 from the middle arm of Taconite Inlet, the surface water of the inlet was probably strongly brackish to marine suggesting that the entrance to Taconite Inlet was not blocked by an ice shelf at the time of separation. The deep water of these future lakes probably became isolated from the general estuarine circulation and began to develop some of their present limnological features prior to actual separation of the surface waters of the lakes from the inlet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176936
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  • 96
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    A reconnaissance study of oxygen, hydrogen and strontium isotopes in geochemically diverse lakes, Western Nebraska, USA (1997)
    Springer
    Journal of paleolimnology 17 (1997), S. 51-65 
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    ISSN: 1573-0417
    Keywords: Stable isotopes ; strontium isotopes ; hydrology ; paleolimnology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Reconnaissance δ18O,, δD, and δ87Sr data for fifteen lakes in the Western Lakes Region of the Sand Hills of Nebraska indicate dynamic hydrologic systems. The rather narrow range of δ87Sr from lake water (1.1 to 2.1) and groundwater (0.9 to 1.7) indicates that the groundwater is generally unradiogenic. Groundwater residence times and relatively unradiogenic volcanic ash within the dune sediments control the δ87Sr values. Based on the mutual variations of δ18O and δD, the lakes can be divided into three groups. In Group 1, both δ18O and δD values increase from spring to fall. The δ18O and δD values in Group 2 decreased from spring to fall. Group 3 are ephemeral lakes that went dry some time during 1992. The data and isotopic modeling show that variations in the ratio of evaporation relative to groundwater inflow, local humidity conditions, and the δa has substantial influence on the isotopic composition. In addition, isotopic behavior in ephemeral lakes can be rather unusual because of the changing activities of water and mineral precipitation and redissolution. The annual and interannual isotopic variability of these lakes which is reflected in the paleonvironmental indicators may be the rule rather than the exception in these types of systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007913010057
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  • 97
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    Changes in the importance of lotic and littoral diatoms in a high arctic lake over the last 191 years (1996)
    Springer
    Journal of paleolimnology 16 (1996), S. 187-204 
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    ISSN: 1573-0417
    Keywords: diatoms ; lotic diatoms ; varves ; paleolimnology ; turbidities ; high arctic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Both habitat preferences and community associations for some of the most prominent pennate taxa in our profile were established using samples from the modern lake and its watershed. Habitat preferences were used to establish a simple indicator for the relative contribution of lotic communities in this lake (Lotic Index) and indicator taxa for both littoral (Achnanthes spp. and Cymbella spp.) and lotic (Hannaea arcus and Meridion circulare) communities. When profiled, the Lotic Index showed a clear positive relationship to sedimentation rate as recorded in the varves, while profiles of littoral indicator taxa show the opposite trends. It seems likely that the patterns we observed in the Lotic Index are related to changes in runoff. Apparently, there was a period of declining runoff beginning ca. two centuries ago and ending in the late 1800's. This was followed by increasing runoff lasting until the middle of the 20th century. A brief minimum occurred in ca. 1970 followed by a recovery by ca. 1980. A strong positive relationship was also found between the dates of major turbidites, exceptionally thick varves and the concentration of valves in the sediment. It is possible that many of the thicker varves in the profiles contain littoral material transported to the site of deposition by turbid interflows and underflows. For this reason, the concentration of valves in the sediment in our cores appears to be a proxy for sediment deposition from turbidity currents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176935
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  • 98
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    Late Quaternary climates and limnology of the Lake Winnebago basin, Wisconsin, based on ostracodes (1997)
    Springer
    Journal of paleolimnology 18 (1997), S. 249-260 
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    ISSN: 1573-0417
    Keywords: Quaternary ; paleoclimates ; paleolimnology ; ostracodes ; Wisconsin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Ostracodes document a series of late Quaternary climatic and limnologic changes within the Lake Winnebago basin of east-central Wisconsin. Using a 14 C, 137Cs, and 210Pb-based geochronology, Lake Winnebago ostracode abundances were compared to regional patterns of ostracode biogeography and the paleontological, sedimentological, and geochemical records of Elk Lake (Clearwater County), Minnesota, in order to interpret past temperature and hydrochemical changes in Lake Winnebago. Lake Winnebago sediments contain five major ostracode species, Candona ohioensis, Candona rawsoni, Cytherissa lacustris, Limnocythere verrucosa, and Physocypria pustulosa. In combination with sedimentology and geochronology, variations in the abundances of these species allow the late Quaternary record of the Lake Winnebago basin to be subdivided into five major climatic intervals: (1) glacial to post-glacial (15.5–11.0 ka), (2) cold and variable immediate post-glacial (11.0–10.4 ka), (3) warmer and wet early Holocene (10.4–7.8 ka), (4) warm but not particularly dry middle Holocene (7.8–4.2 ka), and (5) warm and moist late Holocene (4.2 ka-present).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007930402632
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  • 99
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    Thecamoebians in Lake Winnipeg: a tool for Holocene paleolimnology (1998)
    Springer
    Journal of paleolimnology 19 (1998), S. 309-328 
    Details
    ISSN: 1573-0417
    Keywords: agglutinated rhizopods ; testate amoebae ; thecamoebians ; Lake Winnipeg ; paleolimnology ; Holocene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Holocene sediments in Lake Winnipeg are expressed in the lower Lake Agassiz sequence which is unconformably overlain by the Lake Winnipeg sequence. Nine sites, covering the North and South basins and the connecting Narrows, were selected for analysis of Holocene changes in thecamoebian faunae. Only the Lake Winnipeg sequence contains thecamoebians. This study indicates that biologic productivity and consequently the type of organic material in the sediments is the main control on thecamoebian taxa in Lake Winnipeg. Other factors controlling the distribution of thecamoebians are water chemistry and turbidity. Inorganic sediment geochemistry and water temperature do not appear to significantly influence the thecamoebian fauna of Lake Winnipeg. Variations in the abundance of key thecamoebian species along a north-south transect divide Lake Winnipeg into three distinct areas. The North Basin has remained relatively unchanged since the retreat of Lake Agassiz as indicated by the domination of Difflugia manicata throughout its history. This species appears to prefer Cyanophyta and diatoms as its food source. In the Narrows harsh conditions created by turbid waters and lack of algal food taxa result in Centropyxis aculeata replacing Difflugia manicata as the dominant species. In the South Basin three thecamoebian assemblages are recognized. Cucurbitella tricuspis, indicative of eutrophic conditions, dominates the most recent sediments of the South Basin. The underlying sediments are characterized by Difflugia globulus. In Lake Winnipeg this species is not a cold climate (arctic) indicator as suggested elsewhere but instead seems to prefer sediments containing green and yellow-green algal material. A Centropyxis-Arcella Assemblage occurs only at the base of the southernmost core where it is indicative of an early phase of hyposaline conditions as developed in shallow pools during the southward transgression of Lake Winnipeg. This study illustrates the usefulness of thecamoebians as paleolimnological indicators. Environmental changes are more significant in the restricted South Basin resulting in distinct thecamoebian assemblages. In contrast, the North Basin provided a stable environment throughout the late Holocene reflected in only subtle faunal changes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007942301638
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  • 100
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    Opaline concretions in Weichselian Late-glacial lake marl from Flanders, northern Belgium (1998)
    Springer
    Journal of paleolimnology 20 (1998), S. 91-98 
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    ISSN: 1573-0417
    Keywords: opal-A ; biogenic silica ; lake levels ; Allerød ; Weichselian Late-glacial ; paleolimnology ; Belgium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Macroscopic opal-A concretions were observed in lake marl deposited in a small Flemish lake (Belgium) during the Allerød biozone of the Weichselian Late-glacial (ca. 12–11 ka BP). The silica from these concretions was derived within the profile, by the leaching of siliceous microfossils – mainly diatom frustules. Formation of the concretions probably resulted from pH- and/or evaporation related precipitation of the silica at a lower stratigraphic level, presumably corresponding more or less to a former low position of the groundwater table. The presence of these concretions is probably related to alternatingly wet and dry local conditions during the middle and later part of the Allerød.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007900315210
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