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  • Lepidoptera  (62)
  • phosphorus  (43)
  • Coleoptera  (39)
  • Springer  (143)
  • 2020-2024
  • 1990-1994  (143)
  • 1992  (143)
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  • 2020-2024
  • 1990-1994  (143)
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  • 1
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Braconidae ; Lepidoptera ; Pieridae ; cabbage ; tritrophic interactions ; semiochemicals ; host-habitat location ; foraging behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Upon initiating a research project on the role of volatile infochemicals in the tritrophic system Cotesia (= Apanteles) glomerata (L.)-Pieris brassicae (L.)-cabbage, a bioassay was developed to investigate the response of C. glomerata. The bioassay should be effective in terms of high responsiveness and minimum variability and constructed through a comparative approach. Twenty seven treatments, organized in a factorial randomized block design, compared the effect of three bioassay set-ups (glasshouse flight chamber, wind-tunnel and Y-tube olfactometer), three parasitoid age groups (1–2, 4–5 and 8–9 days old females), three pre-treatment experiences (naive, damage experienced and oviposition experienced wasps) and the day-to-day effect on response of C. glomerata to clean cabbage (CC) and planthost complex (PHC) in a dual choice test. The best results with regard to the strength and consistency of response to the PHC were obtained in the glasshouse flight-chamber by 4–5 days old female wasps with either damage or oviposition experience (94 and 90%, respectively). It is therefore recommended as a suitable bioassay for studying the role of volatile infochemicals in host-habitat location by C. glomerata. A day-to-day variation in response was found in the glasshouse and wind-tunnel. It was correlated with the direction of change in barometric pressure within the time period of the experiment, showing that steadily increasing atmospheric pressure yields a significantly higher response than steadily decreasing or fluctuating barometric flux. To control for the day effect it is suggested to conduct further experiments in a block design, having day as a block. Several aspects of the infochemical ecology of C. glomerata are discussed.
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  • 2
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    Entomologia experimentalis et applicata 63 (1992), S. 115-121 
    ISSN: 1570-7458
    Keywords: Pea weevil ; Bruchus pisorum ; Bruchidae ; Coleoptera ; flower feeding ; nectar robbing ; pea ; Pisum sativum ; resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pea flower feeding by adult pea weevils, Bruchus pisorum (L.) (Coleoptera: Bruchidae), with special emphasis on nectar feeding, was investigated in a series of laboratory experiments. Male and female adults robbed nectar from flowers of the garden and field pea, Pisum sativum L., and females which fed on the nectar, petals, and female organs of pea flowers lived significantly longer than those denied food and water and those that fed on water only. The results of other experiments suggested that pea flower qualities other than pollen influenced the reproductive success of female B. pisorum. It is hypothesized that pollen seeking B. pisorum effected cross-pollination in the wild progenitor of the modern-day autogamous pea, and adult pea weevils of both sexes rob pea nectar to obtain a readily available source of energy to sustain flight.
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  • 3
    ISSN: 1570-7458
    Keywords: Ceutorhynchus inaffectatus ; Coleoptera ; Curculionidae ; Hesperis matronalis ; Dame's violet ; Brassicaceae ; Cruciferae ; glucosinolates ; feeding stimulants ; host plant specificity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ceutorhynchus inaffectatus Gyllenhal (Coleoptera: Curculionidae:Ceutorhynchinae) is a monophagous species feeding only onHesperis matronalis L. (Cruciferae) in North-western Europe. Feeding responses of this weevil to five glucosinolates from its host plant were compared with the responses to four glucosinolates from non-host plants. The major glucosinolates in the host plant were isolated and identified: 6-methylsulphinylhexylglucosinolate (glucohesperalin), 3,4-dihydroxybenzylglucosinolate (glucomatronalin), 3-O-apiosylglucomatronalin, a 3,4-dihydroxybenzoylester and a 3,4-dimethoxybenzoylester of 3-O-apiosylglucomatronalin. The three glucosinolates containing apiose were powerful feeding stimulants forC. inaffectatus while the other host plant compounds and allyglucosinolate (sinigrin), 3-methylsulphinylpropylglucosinolate (glucoiberin), benzylglucosinolate (glucotropaeolin) and p-hydroxybenzylglucosinolate (sinalbin) were weaker stimulants. The role of glucosinolates in host plant selection ofC. inaffectatus and related monophagous crucifer feeders is discussed.
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  • 4
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    Entomologia experimentalis et applicata 63 (1992), S. 3-12 
    ISSN: 1570-7458
    Keywords: Feeding ; behaviour ; food preference induction ; diets ; Manduca sexta ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Diet-induced changes in food preference by fifth instar larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera, Sphingidae), were examined. Two groups of larvae with different diet experience were used: larvae reared on a host or on an acceptable non-host plant species. Each group of larvae was offered a choice between leaf discs from each rearing plant species (2-plant choice test) and food preference was measured as the consumption of one plant species relative to that of the other plant species. Diet-induced changes in preferences were larger with the host versus acceptable non-host plant pairs Solanum pseudocapsicum (L.) versus Raphanus sativus (L.), Lycopersicon esculentum (Mill.) versus Vigna sinensis (Savi), and Datura innoxia (L.) versus V. sinensis than with the host versus host plant pairs L. esculentum versus Capsicum annuum (L.) and L. esculentum versus D. innoxia. To examine how much the food preference had been altered for each test plant species alone, two other groups of larvae were offered a choice between leaf discs from a single plant species and filter paper discs laced with distilled water (1-plant choice test). Larvae preferred the dietary plant species more strongly than the non-dietary plant species in tests using the following plant species: for C. annuum with C. annuum and L. esculentum as diets, for V. sinensis with V. sinensis and L. esculentum or D. innoxia as diets, and for R. sativus with R. sativus and S. pseudocapsicum as diets. The preference for the hosts L. esculentum and D. innoxia did not change significantly after rearing larvae on different hosts or on an acceptable non-host. Thus, diet-induction by M. sexta larvae results in an enhancement of preference for the dietary plant species which is much stronger with acceptable non-hosts than with hosts.
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  • 5
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    Entomologia experimentalis et applicata 62 (1992), S. 87-91 
    ISSN: 1570-7458
    Keywords: Molting ; Lepidoptera ; nutritional indices
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 6
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    Entomologia experimentalis et applicata 63 (1992), S. 81-86 
    ISSN: 1570-7458
    Keywords: Laboratory bioassay ; olfactometer ; olive bark beetle ; Phloeotribus scarabaeoides ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bioassay conditions with a glass olfactometer for the olive bark beetle, Phloeotribus scarabaeoides Bern. (Coleoptera: Scolytidae), have been investigated. The best temperatures and light intensities were between 17 and 28° C and 1000 and 1500 lux, respectively. The best response was obtained with newly emerged individuals from reproduction galleries with no feeding period.
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  • 7
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    Entomologia experimentalis et applicata 65 (1992), S. 75-80 
    ISSN: 1570-7458
    Keywords: Pyralidae ; Lepidoptera ; Zea mays L. ; Chilo partellus ; susceptibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The resistance/susceptibility levels of ten maize (Zea mays L.) cultivars to neonates and 3rd-instar larvae of Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) were measured in the field and screenhouse experiments. The maize cultivars tested were: Inbred A, Mp 704, V-37, Population 10, Hybrid 511, Katumani Composite B, ER-29 SVR, Poza Rica 7832, ICZ2-CM, and MMV 400. Most cultivars were found susceptible to 3rd-instar larvae based on the incidence of dead heart symptoms, foliar feeding and stem tunnelling caused by stem borers in both the field and screenhouse experiments. However, the maize cultivars V-37, MMV 400 and Poza Rica 7832 sustained significantly lesser damage than the other cultivars when infested with neonates or 3rd instar larvae. The screenhouse experiments conducted with five maize cultivars, i.e. Inbred A, Mp 704, V-37, ER-29 SVR, and Poza Rica 7832 showed that neonates fed less on the resistant than the susceptible maize cultivars but feeding by the 3rd instars was equally high on all the maize cultivars except Mp 704 on which the larvae fed less than the others. In the cultivars infested with neonates, the mean period for 50% moth emergence P50 was longest on Mp 704 followed by Poza Rica 7832, ER-29 SVR, V-37 and Inbred A. In the cultivars infested with 3rd-instars, P50 was longest for Poza Rica 7832 followed equally by the remaining cultivars. On the basis of the evidence presented we here conclude that neonates of C. partellus are sensitive to the growth inhibiting effects of the resistant maize cultivars Mp 704, V-37, and Poza Rica 7832 but the older larvae are insensitive to these effects of Mp 704 and V-37 but not of Poza Rica 7832.
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  • 8
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    Entomologia experimentalis et applicata 65 (1992), S. 129-140 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Carabidae ; Bembidion lampros ; Pterostichus cupreus ; P. melanarius ; diet ; egg production ; egg size variation ; pirimicarb ; fat reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Egg size was measured at different rates of egg laying in three polyphagous carabid species, known to be useful predators of cereal aphids; the small Bembidion lampros Herbst and the medium-sized Pterostichus cupreus L. and P. melanarius Illiger. Variations in fecundity, as well as the ability of the medium-sized species to also build up fat reserves, were obtained when beetles were subjected to different dietary regimes consisting of aphids, or foods with a lower or higher protein content. Egg size was found to be dependent on the rate of egg laying within a species. A diet of cereal aphids appeared to be adequate for egg production in these polyphagous carabids, but female P. cupreus were unable to build up fat reserves when they ingested aphids contaminated with the aphicide pirimicarb. Beetles were able to devote resources to more and larger eggs (B. lampros), or to larger eggs and/or fat reserves (P. melanarius/P. cupreus) when given access to a carbohydrate-rich food with low protein content. The highest rate of egg laying was obtained when female P. cupreus and P. melanarius were given a more varied diet at frequent intervals; including regular shifts between unsprayed aphids, carbohydrate-rich food and protein-rich maggots. Within the varied diet treatment a negative relationship was obtained between egg size and egg number among similar-sized individuals of P. cupreus and P. melanarius; females producing the largest number also laid the smallest eggs. Egg size affected larval survival, since first instars hatching from large eggs were found to survive longer than those hatching from small eggs. The influence of differences in food intake on reproduction, maintenance metabolism, and survival of fieldinhabiting carabids is discussed.
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  • 9
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    Entomologia experimentalis et applicata 65 (1992), S. 235-240 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Tenebrionidae ; Pterohelaeus darlingensis ; Gonocephalum macleayi ; false wireworms ; sampling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Counts of adults of the false wirewormsGonocephalum macleayi (Blackburn) andPterohelaeus darlingensis Carter in pitfall traps in burnt, mulched and sorghum treatments conformed to Taylor's power law. Within a species there were no significant differences in distributions of counts of either sex in any habitat butG. macleayi were more aggregated thanP. darlingensis (Taylor'sb 1.35 and 1.26, respectively). Relationships to determine sample sizes for fixed levels of precision and fixed-precision-level stop lines for sequential sampling are developed for each species using Taylor's parameters for combined data over all habitats.
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  • 10
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    Entomologia experimentalis et applicata 65 (1992), S. 247-257 
    ISSN: 1570-7458
    Keywords: Population genetics ; microgeographic differentiation ; leaf-beetles ; Chrysomelinae ; Coleoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We usedF-statistics to quantify the population structure of two sympatric species of leaf beetles,Oreina cacaliae andO. speciosissima (Chrysomelinae, Coleoptera), which share the same microhabitat since they feed on the same herbaceous host plants. We measured genetic differentiation at six allozyme loci 1) among populations separated by relatively small distances (40 to 250 kilometers), 2) within each population, and 3) between sexes within populations. For both species, the populations studied are not panmictic. For each population, heterozygosities are relatively high, but the observed heterozygosities are generally lower than the expected values. Overall, within-population differentiation is high and similar for both species (F is=0.326 forO. cacaliae and 0.332 forO. speciosissima). Additionally, populations of both species are highly differentiated (F st=0.234 versus 0.051 forO. speciosissima). ForO. cacaliae,F is andF st are greater among females than among males, while forO. speciosissima,F st is sustantially greater among the males whileF is is slightly greater among males. Differences in gene frequency among the sexes were statistically tested using a modifiedF st with sex as the defining category, and the sexes differed significantly with the exception of one population inO. cacaliae. Possible explanations for this difference are discussed.
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  • 11
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    Entomologia experimentalis et applicata 65 (1992), S. 39-47 
    ISSN: 1570-7458
    Keywords: Development ; fecundity ; geographical variation ; Coleoptera ; Bruchidae ; ecology ; Phaseolus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Zabrotes subfasciatus (Boheman) (Coleoptera:Bruchidae) is native to parts of Central and South America but has now been spread to many others areas. It commonly infests the seeds of both Lima beans, Phaseolus lunatus, and common beans, Phaseolus vulgaris. Five geographic populations were found to differ in fecundity, patterns of egg distribution, times of development and adult sizes when they were kept under the same conditions. Each population also differed unpredictably from the others in its response to different cultivars of host seed. These differences have been shown to be of considerable importance in determining the potential pest status of the populations and should also promote caution in making predictions about the responses of different populations to new cultivars of bean for agricultural use.
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  • 12
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    Entomologia experimentalis et applicata 65 (1992), S. 165-170 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; stem borer ; suction trap ; behaviour ; maize ; dispersal ; pheromones ; activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diel flight periodicity of the nocturnal moth Chilo partellus (Swinhoe) (Lepidoptera;Pyralidae) was measured in the laboratory using an actograph and in the field with suction traps. Females showed almost no flight activity on the night of eclosion. Flight activity of mated females peaked before midnight, the period of peak oviposition activity. Male peak activity occurred after midnight coinciding with female eclosion. Presence or absence of females did not affect when or how long males were active. Data on flight activity and reproductive behaviour are discussed in relation to the use of pheromones to protect maize.
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  • 13
    ISSN: 1572-8889
    Keywords: Heliothis virescens ; Noctuidae ; Lepidoptera ; upwind flight ; sex pheromone ; filaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aspects of the intermittent fine structure of an odor plume were mimicked and experimentally modified in the wind tunnel using an air-pulsing device. Filaments of a behaviorally active blend of six sex-pheromone components created by the device in a temporally regular fashion elicited sustained upwind flight and source location in male Heliothis virescens.Males did not exhibit sustained upwind flight in significant numbers until a frequency of 4 filaments/s was delivered, at a loading of 1 μg of the major component, Z11-16: Ald, with the other components loaded at their appropriate ratios. A loading of 10 μg Z11-16: Ald was found to be optimal at this filament delivery rate. Electroantennogram recordings to different filament delivery rates of the complete blend indicated that a stationary male antenna can respond to the pulse rates used in this study. Importantly, when a main component necessary for upwind flight, Z9-14:Ald, was isolated into its own filaments and pulsed alternately against filaments of the five other components (including the other component essential for upwind flight, Z11-16: Ald), upwind flight to the source was significantly reduced (9%) compared to upwind flight and source location in response to filaments composed of the entire blend (30%), indicating that the complete pheromone blend must arrive on the antenna simultaneously for optimal evocation of sustained upwind progress. Neurophysiological evidence from other studies suggests that higher-order interneurons whose phasic response is enhanced when the entire blend is presented simultaneously may be of importance in explaining this behavioral difference stemming from synchronous vsasynchronous arrival of the components.
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  • 14
    ISSN: 1572-8889
    Keywords: sex pheromone ; landing behavior ; visual cues ; Epiphyas postvittana ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of changes in various visual and olfactory properties of a white card surface on the landing position of male Epiphyas postvittanaexhibiting pheromone-mediated flight were studied in a wind tunnel. Males landed predominantly at the most downwind position of a surface in line with the pheromone source, regardless of the strength of the source. The position on the surface that males landed was strongly influenced by visual factors. The landing position of males appeared to be influenced by visual cues along all three axes of the surface. Decreases in either the dimension horizontally perpendicular to the wind direction or the vertical dimension resulted in greater numbers of males landing farther upwind on the surface than the downwind edge. Visual changes in the axis along the wind direction also affected the position at which males landed. For example, when presented with two white card surfaces with a 4- cm gap between them, males tended to land on the downwind edge of the upwind surface (on which the source was located). When the gap was bridged with clear Mylar, the landing pattern was significantly different, with the greater proportion of males landing on the downwind surface. However, when Mylar was placed on the plexiglass floor of the tunnel (in addition to bridging the gap), the landing pattern on the surface was not significantly different from that on the two surfaces without the Mylar bridge. It is suggested that during the prelanding and landing phases of pheromone-mediated flight, male moths orient to visual features of the surface containing the pheromone source rather than to visual features of the source (conspecific female moth) itself.
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  • 15
    ISSN: 1420-9055
    Keywords: Sediment ; interstitial water ; phosphorus ; iron ; persulfate digestion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It is shown that sorption of orthophosphate to iron compounds, formed during persulfate digestion, can cause a significant underestimation of total dissolved phosphorus in interstitial waters rich in iron and poor in phosphorus. Labelling the samples with carrier free32PO4 before digestion allows to correct for these losses.
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  • 16
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    Entomologia experimentalis et applicata 62 (1992), S. 29-36 
    ISSN: 1570-7458
    Keywords: Alkaloids ; cinnabar moth ; insect genetics ; larval performance ; Lepidoptera ; nutritional ecology ; nitrogen ; sugar ; Tyria jacobaeae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a laboratory experiment using full-sibs, 60% of the variation in pupal weight of the monophage Tyria jacobaeae L. (Lepidoptera, Arctiidae) could be explained by variation in the nitrogen concentration of the food plant, Senecio jacobaea L. and only 4% by variation in sugar concentration. Larval weight and growth rates of young and old larvae were also positively correlated with nitrogen and sugar concentration. Developmental time was negatively correlated with nitrogen concentration. In a second experiment full-sib families differed significantly in larval weight at day 7, mortality, growth rate and developmental time. Pupal weight did not differ significantly among families, but was positively correlated with nitrogen concentration of Senecio. Larval performance was not significantly influenced by concentrations of sugars or alkaloids. We conclude that larval performance of Tyria during most of the larval period is mainly determined by genetic factors, but pupal weights are primarily determined by nitrogen concentration of the food plant.
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  • 17
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    Entomologia experimentalis et applicata 65 (1992), S. 81-93 
    ISSN: 1570-7458
    Keywords: Heliothis virescens ; Lepidoptera ; Noctuidae ; feeding behavior ; oviposition behavior ; electrophysiology ; deterrence ; antifeedant ; quinine ; quinidine ; atropine ; caffeine ; denatonium benzoate ; naringin ; sucrose octaacetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some compounds that are bitter-tasting to humans, both alkaloidal (quinine, quinidine, atropine, caffeine) and non-alkaloidal (denatonium benzoate, sucrose octaacetate, naringin), deterred feeding and oviposition by Heliothis virescens (F.) in laboratory and field cage experiments. Preliminary electrophysiological studies of gustatory sensilla on the ovipositor of H. virescens provided evidence of 3 neurons, one of which is responsive to sucrose. Preliminary indications are that responses of this neuron may be inhibited by quinine and denatonium benzoate.
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  • 18
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    Entomologia experimentalis et applicata 65 (1992), S. 199-204 
    ISSN: 1570-7458
    Keywords: Sesamia nonagrioides ; Lepidoptera ; Noctuidae ; calling behaviour ; mating behaviour ; circadian rhythm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mating behaviour of the corn stalk borerSesamia nonagrioides (Lef.) [Lepidoptera:Noctuidae] was studied under laboratory conditions at 25 ± 1 °C, 65 ± 5% r.h. and 16:8 (L:D) regime. The females began calling during the first scotophase following emergence, the peak of calling occurred during the second scotophase and thereafter decreased. Maximum calling was observed between the fourth and sixth hour of the scotophase. The calling pattern varied with age. During the first and second scotophase most of the females were calling continuously, while during the third and fourth scotophase periodic calling was observed. The mean onset of calling was advanced and the mean length of calling per day was increased slightly as the female became older. Females held for 72 h in continuous darkness exhibited an endogenous circadian rhythm of calling. Matings began during the first scotophase following emergence and the peak of mating was observed during the second scotophase. Mated females did not remate. Few males mated more than once during the following scotophases.
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  • 19
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    Journal of comparative physiology 171 (1992), S. 289-297 
    ISSN: 1432-1351
    Keywords: Electrophysiology ; Lepidoptera ; Photoreceptor ; Spectral sensitivity ; Vision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. A butterfly Papilio has 5 types of spectral receptors in the compound eye. The spectral sensitivity of each type peaks in the UV, violet, blue, green, and red wavelengths, respectively. The green type contains two subtypes with and without a UV secondary peak. Here we studied the localization of these spectral receptors within the ommatidium. 2. An ommatidium contains 9 photoreceptors (R1–9), each of which is one of the 5 spectral receptor types. The photoreceptors bear parallel microvilli to form a nontwisted rhabdom, and thereby the photoreceptors are polarization sensitive. 3. We first examined the microvillar orientation by electron microscopy. The microvilli of R1, 2, and 9 are oriented dorso-ventrally (0°), whereas those of R3 and 4 are parallel to the antero-posterior axis (90°). The R5–8 bear microvilli diagonally: 45° for R6 and R8, 135° for R5 and R7. 4. We then recorded spectral and polarization sensitivities from single photoreceptors. The peak angle of the polarization sensitivity (θmax) of the UV, violet, and blue receptors were around 0°, whereas that of the green receptors was around 90°. In the double-peaked green receptors, the θmax at UV was also around 90°. The red receptors showed a θmax at around 35°. The polarization sensitivity ratio (PSmax/PSmin) of the double-peaked green receptors measured at UV was around 4, whereas the ratio of other receptors was around 2. 5. We conclude that R1 and R2 are either UV, violet, or blue receptors whereas R3 and R4 are green receptors. Some R6 and R8 are red receptors. We also conclude that the UV secondary peak in the double-peaked green receptor is not simply attributable to the coupling with UV receptors.
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  • 20
    ISSN: 1432-1351
    Keywords: Carbon dioxide ; Chemoreception ; Lepidoptera ; Microclimate ; Sensory transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In recordings of single unit action potentials, the responses of CO2-receptors in the labial palp organ of the moth Heliothis armigera to modulation of CO2-density around a background of 350 ppm were investigated. Modulation of CO2-density by square wave changes in concentration at constant barometric pressure evokes modulation of the spike rate. Modulation of CO2-density by square wave changes in barometric pressure at constant CO2-concentration evokes responses similar to those evoked by concentration modulation. For modulation depths of less than 1.5%, the output modulation depth is linearly related to the input; at higher modulation depths the gain decreases progressively. Using sinusoidal pressure modulation, the frequency dependence of both gain and output noise was determined over a range of 0.05 to 12.8 Hz. With increasing frequency the gain progressively increases at a rate of 2.4 dB/octave up to a maximum of 63 at 3 Hz; at higher frequencies, it decreases rapidly. The threshold sensitivity of the receptors, using input noise amplitude density as a criterion, is broadly tuned, with a minimum of 1 % contrast Hz-0.5 between 0.3 and 3 Hz. Using these figures, it is concluded that the sensory organ is capable of detecting fluctuations in CO2-density of 0.14% or 0.5 ppm. The results are related to the fluctuations in CO2-density which occur in a natural environment.
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  • 21
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    Microchimica acta 109 (1992), S. 201-209 
    ISSN: 1436-5073
    Keywords: phosphonate base scale inhibitor ; brine ; direct current plasma ; inductively coupled plasma atomic emission spectrometry ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The determination of phosphonate base scale inhibitors in brines by direct current plasma (DCP) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The first method is based on a direct nebulization of the brine samples and plasma using the phosphorus line at 213.618 nm. The second method involves extraction of phosphorus as phospho-antimonyl molybdate complex into methylisobutyl ketone (MIBK) phase and analysis of the extract for molybdenum using the Mo 313.260 nm line. Comparison between the proposed methods and an established recommended method [1] shows excellent agreement between the results in addition to the sensitivity and ease of automation provided by AES.
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  • 22
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    Nutrient cycling in agroecosystems 32 (1992), S. 223-227 
    ISSN: 1573-0867
    Keywords: Soil testing ; phosphorus ; relative yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A greenhouse experiment, with Okra (Abelmoschus esculentus L.) as the test crop, was conducted on twenty-one soils ranging in Olsen's extractable phosphorus from 1.8 to 15.5µg Pg−1 soil. The experiment was conducted at Punjab Agricultural University, Ludhiana, India. The soils were nonsaline with pH ranging from 7.7 to 8.6. A critical level of 2.55µg Pg−1 soil was predicted by Cate and Nelson's (1971) statistical procedure. Because of a wide range in relative yields, this value did not accurately predict response to applied P. An approach to compute minimum response to applied fertilizer, which is likely to be obtained at a particular Olsen P level, has been presented. It involves calculation of lower 60 percent confidence limits for relative yield and fitting loge-linear regression to the transformed data. The regression was tested on a published data set and was found to hold well.
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  • 23
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    Nutrient cycling in agroecosystems 32 (1992), S. 259-267 
    ISSN: 1573-0867
    Keywords: Nitrogen ; phosphorus ; timber increment ; fertilization ; Pinus radiata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two trials inPinus radiata growing on different sites in N.S.W. allowed consideration of fertilizer applications after 2nd or 3rd thinning. The trials included factorial applications of N and P at a single thinning intensity plus a further treatment which allowed assessment of different thinning intensities. The most significant growth responses were obtained by application of N and P in combination. The largest response (additional productivity compared with the unfertilized control) occurred 4 years after application and after 7 years there was no additional absolute response for either of the two sites. The largest fertilizer response was 70 m3 ha−1 over 7 years on one site and 36 m3 ha−1 on the other, indicating differences in absolute responses between sites. It was concluded that in planning treatments the most responsive sites near the end of the rotation should be selected to maximise economic returns. Foliage analyses indicated differences between sites at the commencement of the study. It was concluded that either a single year of foliage analyses at study commencement is of value, or sampling every year of the study should be used to analyse responses, but a single year of analysis during or at the end of the study would not be of value.
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  • 24
    ISSN: 1423-0445
    Keywords: defensive chemistry ; alterable ; elicitation ; herbivory ; antioxidant ; Fabaceae ; Glycine max ; Lepidoptera ; Noctuidae ; Trichoplusia ni
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The water-soluble antioxidant, L-ascorbic acid (vitamin C), proved elicitory to alterable anti-herbivory inGlycine max againstTrichoplusia ni larvae. Elicitation by vitamin C was influenced especially by dose, time after elicitation and space in the plant. Results allow an analogy between antioxidant and herbivory elicitation. Elicitation apparently involves a sulfhydryl-protein-dependent redox mechanism which can be significantly affected by antioxidants. Findings would also support a proposed common redox-based mechanism, involving the plasma membrane, for communication between plant and animal cells and their environments.
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  • 25
    ISSN: 1423-0445
    Keywords: specificity ; predation ; long-range orientation ; windtunnel ; Coleoptera ; Rhizophagidae ; Scolytidae ; Rhizophagus grandis ; Dendroctonus micans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The predator,Rhizophagus grandis, is linked to its specific prey,Dendroctonus micans, by semiochemical signals regulating oviposition and long range orientation. A mixture of simple oxygenated monoterpenes [(−)—fenchone, (−)—pinocamphone, rac. camphor, terpinene-4-ol, borneol, fenchol and verbenone], identified from the frass ofD. micans has been found to be extremely active in a flight windtunnel as a long—range attractant for the predator. The mixture elicited 84 % of the response to larval frass of the prey. Excluding pinocamphone from the mixture did not influence its activity. Also, changing the absolute configurations of some of the components (fenchol, terpinene-4-ol and borneol) did not influence the predators' response. However, the addition of (−)—α-terpineol increased the attractivity of the synthetic blend to almost that of larval frass of the prey. Ecological implications of the identified semiochemicals and their use in pest management are discussed.
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  • 26
    ISSN: 1423-0445
    Keywords: aposematism ; cardenolide fingerprint ; chemical defense ; emesis ; plant-insect interaction ; migration ; Asclepiadaceae ; Apocynales ; Asclepias humistrata ; milkweed ; Lepidoptera ; Danainae ; Danaus plexippus ; monarch butterfly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This paper is the fourth in a series on cardenolide fingerprints of monarch butterflies (Danaus plexippus, Danainae) and their host-plant milkweeds (Asclepiadaceae) in the eastern United States. Cardenolide concentrations ofAsclepias humistrata plants from north central Florida ranged from 71 to 710 µg/0.1 g dry weight, with a mean of 417 µg/0.1 g. Monarchs reared individually on these plants contained cardenolide concentrations ranging from 243 to 575 µg/0.1 g dry weight, with a mean of 385 µg/0.1 g. Cardenolide uptake by butterflies was independent of plant concentration, suggesting that sequestration saturation occurs in monarchs fed cardenolide-rich host plants. Thinlayer chromatography resolved 19 cardenolides in the plants and 15 in the butterflies. In addition to humistratin,A. humistrata plants contained several relatively non-polar cardenolides of the calotropagenin series which are metabolized to more polar derivatives in the butterflies. These produced a butterfly cardenolide fingerprint clearly distinct from those previously established for monarchs reared on otherAsclepias species. In emetic assays with the blue jay,Cyanocitta cristata, the 50% emetic dose (ED50) per jay was 57.1 µg, and the average number of ED50 units per butterfly was 13.8, establishing that this important south eastern milkweed produces highly emetic, chemically defended monarchs. Our data provide further support for the use of cardenolide fingerprints of wild-caught monarchs to make ecological predictions concerning defence against natural enemies, seasonal movement and larval host-plant utilization by monarch butterflies during their annual cycle of migration, breeding and overwintering.
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  • 27
    ISSN: 1423-0445
    Keywords: sequestration ; pharmacophagy ; defense ; allomone ; kairomone ; cucurbitacin ; Cucurbitaceae ; Coleoptera ; Chrysomelidae ; Luperini ; Diabrotica ; Aulacophora
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.
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  • 28
    ISSN: 1423-0445
    Keywords: oviposition ; 3-indolylmethyl glucosinolate ; sinigrin ; glucoiberin ; cabbage ; Cruciferae ; Brassica oleracea ; Lepidoptera ; Pieridae ; Pieris rapae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chemical stimulation of oviposition byPieris rapae on cabbage was investigated by leaf washing and extraction. Isolation of the stimulant by various chromatographic techniques was monitored by a bioassay using Sieva bean as a surrogate host plant. Cold water, chloroform, or chloroform followed by cold water washes failed to release the stimulant from leaf surfaces. Boiling water or chloroform followed by methanol was required. The most active stimulatory compound was identified as 3-indolylmethyl glucosinolate (glucobrassicin). Other glucosinolates were identified as sinigrin, which was only slightly active, and glucoiberin, which was completely inactive as a stimulant. The significance of the selective response ofP. rapae andP. brassicae to different glucosinolates and the implications of the binding of polar allelochemicals to leaf surfaces is discussed with respect to host utilization and perception mechanisms of pierids.
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  • 29
    ISSN: 1423-0445
    Keywords: first instar survival ; latex ; cardiac glycosides ; cardenolides ; Lepidoptera ; Danainae ; Danaus plexippus ; Asclepiadaceae ; Asclepias humistrata ; milkweed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our paper addresses field survivorship of first instar monarch butterfly larvae (Danaus plexippus L., Lep.: Danainae) in relation to the dual cardenolide and latex chemical defenses of the sand hill milkweed plant,Asclepias humistrata (Asclepiadaceae) growing naturally in north central Florida. Survival of first instar larvae in the field was 11.5% in the first experiment (15–20 April 1990), and dropped to 3.4% in the second experiment (20–30 April). About 30% of the larvae were found glued to the leaf surface by the milkweed latex. Predator exclusion of non-flying inverte-brates by applying “tanglefoot” to the plant stems suggested that the balance of the mortality was due to volant inverte-brates, or to falling and/or moving off the plants. Regression analyses to isolate some of the other variables affecting survivorship indicated that first instar mortality was correlated with (1) increasing cardiac glycoside concentration of the leaves, (2) increasing age of the plants, and (3) the temporal increase in concentration of cardiac glycosides in the leaves. The study also provided confirmatory data of previous studies that wild monarch females tend to oviposit onA. humistrata plants containing intermediate concentrations of cardiac glycosides. Cardiac glycoside concentration in the leaves was not correlated with that in the latex. The concentration of cardenolide in the latex is extremely high, constituting an average of 1.2 and 9.5% of the mass of the wet and dry latex, respectively. The data suggest that an increase in water content of the latex is compensated for by an influx of cardenolide with the result that the cardenolide concentration remains constant in the latex systems of plants that are growing naturally. We also observed first instar larvae taking their first bite of milkweed leaves in the field. In addition to confirming other workers findings that monarch larvae possess elaborate “sabotaging” behaviour of the milkweed's latex system, we discovered that several larvae on their first bite involuntarily imbided a small globule of latex and instantly became cataleptic. This catalepsis, lasting up to 10 min, may have been in response to the high concentration of cardenolide present in the latex ofA. humistrata, more than 10 times that in the leaves. The results of the present study suggest that more attention should be directed to plant chemical defenses upon initial attack by first instar insect larvae, rather than attempting correlations of plant chemistry with older larvae that have already passed the early instar gauntlet. The first bite of neonate insects may be the most critical moment for coping with the chemical defenses of many plants and may play a much more important role in the evolution of insect herbivory than has previously been recognized.
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  • 30
    ISSN: 1423-0445
    Keywords: chemical defence ; tri-trophic interactions ; alkaloids ; Homoptera ; Aphis craccivora ; Icerya spp. ; Lepidosaphes ulmi ; Planococcus citri ; Coleoptera ; Coccinellidae ; Cryptolaemus montrouzieri ; Rodolia cardinalis ; Chilocorus bipustulatus ; Neuroptera ; Chrysopidae ; Chrysoperla carnea ; Hymenoptera ; Encyrtidae ; Encyrtus infelix ; Leguminosae ; Erythrina corallodendrum ; Spartium junceum ; Citrus sinensis ; Euphorbia tirucalli ; Pittosporum tobira
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.
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  • 31
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    Cellular and molecular life sciences 48 (1992), S. 1023-1027 
    ISSN: 1420-9071
    Keywords: Chrysolina fuliginosa ; Coleoptera ; Chrysomelidae ; beetles ; cardenolides ; eggs ; glands ; chemical defence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Besides the known sarmentogenin 3-O-β-D-allopyranoside (1) and digitoxigenin-3-O-[β-D-xylopyranosyl-(1→4)-2′, 3′-di-O-acetyl-β-D-allopyranoside] (4), four new cardiac glycosides (2, 3, 5 and6) have been isolated from the defensive glands of adults ofChrysolina fuliginosa. The structures of the new compounds were determined by1H NMR at 600 MHz and FABMS. Compounds1–6, present in the adults ofC. fuliginosa, have also been identified in the eggs.
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  • 32
    ISSN: 1420-9071
    Keywords: Oviposition-deterring pheromone ; Lepidoptera ; Tortricidae ; Lobesia botrana ; eggs ; fatty acids ; esters of fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The oviposition of the European grapevine moth (EGVM)Lobesia botrana can be deterred by an extract of conspecific eggs corresponding to 20 egg equivalents. The reduction of the oviposition behavior is dose-dependent. Nine chemicals have been extracted from the eggs and identified as straight chain fatty acids and esters of fatty acids. A mixture of these rather simple molecules induces the same levels of deterrence as the total extract. It might be possible to use oviposition regulating pheromone in the future for the control of EGVM populations.
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  • 33
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    Aquatic sciences 54 (1992), S. 58-76 
    ISSN: 1420-9055
    Keywords: Eutrophication ; lake management ; phosphorus ; nitrogen ; chlorophyll-a ; slope estimator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We estimate the response of chl-a (mg · m−3) to changes in concentrations of total phosphorus (TP) by calculating the slopeS = Δchl-a/ΔTP in chl-a =f(TP) graphs. Results show that in years where algae are P-limited oligotrophic lakes respond less (median slope 0.21) to changes in nutrient concentrations than eutrophic lakes, (median slope 0.31) and these again less than hypereutrophic lakes, (median slope 1.02). We find no saturation value for the slope within the TP range considered (6–480 mg · m−3). Chl-a in eutrophic lakes responds more frequently to non-nutrient factors than oligotrophic and hypereutrophic lakes. Results obtained by replacing TP with a new nutrient parameter, TP′ = 0.056 · TP · IN0.226, in which inorganic nitrogen, IN, is factored in, suggest that nitrogen has an influence on chl-a in oligotrophic lakes. Blue-green algae respond less to changes in TP than other algal species, e.g., diatoms.
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  • 34
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    Aquatic sciences 54 (1992), S. 381-390 
    ISSN: 1420-9055
    Keywords: Eutrophication ; phosphorus ; lake restoration ; internal restoration measures for lakes ; Swiss lakes ; Lake Lugano (Lago di Lugano)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most lakes eutrophication is linked to an excessive input of phosphorus. Lake restoration by reduction of P-input (external measure) has led to a considerable drop of the P-concentration in all major Swiss lakes as well as in many other lakes. Internal restoration measures such as artificial mixing, drainage of hypolimnetic water, flushing, aeration, biomanipulation and others serve to improve and accelerate the response of a lake to external measures. For the case of Lago di Lugano, a simple two-box model is employed to demonstrate that a reduction of the P-input to about 25% of the present values is necessary to reach the “P-criterion” (P-concentration below 30 µg/l). Internal measures could possibly accelerate the extremely slow response of the northern basin.
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  • 35
    ISSN: 1423-0445
    Keywords: oviposition ; kairomone ; host plant selection ; indole glucosinolates ; Cruciferae ; Brassica oleracea ; cabbage ; Lepidoptera ; Pieridae ; Pieris brassicae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Chemicals present on the surface of cabbage (Brassica oleracea L.) leaves were extracted by dipping these leaves for 3 s in dichloromethane followed by a 3 s dip in methanol. When offered in dual choice bioassays using green paper cards as a substrate, the methanol extract stimulated oviposition activity byPieris brassicae L. (Lepidoptera: Pieridae) females. The oviposition stimulant was isolated using medium pressure liquid chromatography, reversed-phase HPLC, ion-pair HPLC and ion exchange chromatography. Using1H-NMR spectroscopy, the stimulant could be identified as glucobrassicin (3-indolyl-methyl-glucosinolate). When pure glucobrassicin was offered at a dose identical to that in the crude methanol extract, butterflies did not discriminate between these two substrates in a dual choice test. It is argued that a high sensitivity for indole glucosinolates as host recognition factors may confer an adaptive value for these specialist crucifer feeders. The nutritional significance of their precursor tryptophan and the non-volatile nature of the aglycones formed upon enzymic hydrolysis in damaged tissues are proposed as properties of indole glucosinolates that contribute to this possible adaptive advantage.
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  • 36
    ISSN: 1423-0445
    Keywords: competition ; inhibition ; sex-ratio ; mass-at-tack model ; ipsdienol ; E-myrcenol ; cis-verbenol ; 2-methyl-3-buten-2-ol ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ips duplicatus withI. typographus co-inhabiting Norway spruce (Picea abies (L.) Karst.) would benefit from a pheromone blend distinct from that of the larger competitorI. typographus. GC-MS analysis showed thatI. duplicatus males feeding in the host produced ipsdienol (Id),cis-verbenol (cV),trans-verbenol (tV), myrtenol (Mt), andE-myrcenol (EM) and traces of 2-methyl-3-buten-2-ol (MB).I. duplicatus produced Id in approximately racemic form (48.9-54.5% (+)-(S)-isomer). The amounts of Id and EM released over a 9 day period had a maximum of 250 and 5 ng/h/male, respectively, on day 2. Exposure ofI. duplicatus males to myrcene and α-pinene resulted in the production of small amounts of Id, cV, tV, Mt, andtrans-pinocarveol, but not of EM. In laboratory bioassays with walking beetles, the pheromone component Id alone was weakly attractive while EM was inactive, but in binary combination with Id strongly synergized attraction. A combination of EM and Id at a release rate equivalent to 100–200 males was more attractive in the field than 70 unmated males in a spruce log. The addition of myrcene ( a suggested pheromone precursor of Id) to Id did not enhance trap caches, while addition of EM increased catches 〉 10-fold. Subtracting EM from a blend of Id, EM, cV and MB drastically reduced trap catches while subtraction of cV or MB or both had no significant effect. Addition of EM over a wide concentration range to the synthetic pheromone ofI. typographus did not reduce the attraction of females of this species in the laboratory. A two-species pheromone interaction field test releasingI. typographus pheromone components (MB + cV) at 10–1000 male equivalents (ME) andI. duplicatus pheromone (Id + EM) at 0, 10–1000 ME in all possible combinations showed both positive intraspecific dose-response effects and an interspecific inhibition. Higher release rates of EM appeared to inhibitI. typographus, especially males. In a tree colonization model, the response of the two competing species to their respective pheromones show a good separation during the mass-attack with a small initial cross-attraction. It remains to be shown whether either of the two pheromone systems have in fact evolved in the present sympatry, or if they are an incidental effect of ancestry of these phylogenetically distantIps.
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  • 37
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    Cellular and molecular life sciences 48 (1992), S. 97-102 
    ISSN: 1420-9071
    Keywords: Lepidoptera ; Arctiidae ; pyrrolizidine alkaloids ; cannibalism ; acquired defense ; phagostimulation ; specific hunger
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The mothUtetheisa ornatrix derives protection against predation from systemic pyrrolizidine alkaloids (PAs) that it sequesters as a larva from its foodplants (Leguminosae,Crotalaria spp.). We here show, in laboratory tests, thatUtetheisa deficient in body PA can make up for the chemical shortfall by cannibalizing pupae. We present evidence indicating that cannibalism in larvae is elicited not by hunger, but possibly by PA deficiency itself, and that in making cannibalistic choices larvae prefer PA-containing over PA-free pupae. PAs themselves, either in crystalline form or as additives to food items, proved phagostimulatory to larvae. In natureUtetheisa tend to pupate away from their foodplant, essentially out of reach of larval attack. The threat of cannibalism may have contributed to the evolution of this pupation behavior.
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  • 38
    ISSN: 1432-1939
    Keywords: C3 and C4 grasses ; Lepidoptera ; Hesperiidae ; Paratrytone melane ; Nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We tested the hypothesis that C4 grasses are inferior to C3 grasses as host plants for herbivorous insects by measuring the relative performance of larvae of a graminivorous lepidopteran, Paratrytone melane (Hesperiidae), fed C3 and C4 grasses. Relative growth rates and final weights were higher in larvae fed a C3 grass in Experiment I. However, in two additional experiments, relative growth rates and final weights were not significantly different in larvae fed C3 and C4 grasses. We examined two factors which are believed to cause C4 grasses to be of lower nutritional value than C3 grasses: foliar nutrient levels and nutrient digestibility. In general, foliar nutrient levels were higher in C3 grasses. In Experiment I, protein and soluble carbohydrates were digested from a C3 and a C4 grass with equivalent efficiencies. Therefore, differences in larval performance are best explained by higher nutrient levels in the C3 grass in this experiment. In Experiment II, soluble carbohydrates were digested with similar efficiencies from C3 and C4 grasses but protein was digested with greater efficiency from the C3 grasses. We conclude (1) that the bundle sheath anatomy of C4 grasses is not a barrier to soluble carbohydrate digestion and does not have a nutritionally significant effect on protein digestion and (2) that P. melane may consume C4 grasses at compensatory rates.
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  • 39
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    Oecologia 90 (1992), S. 417-421 
    ISSN: 1432-1939
    Keywords: Coleoptera ; Predator-prey ratios ; Trophic structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In common with samples from less taxonomically constrained studies, significant correlations exist between the numbers of predatory and non-predatory species in assemblages of terrestrial beetles. Under logarithmic transformation the relationship can be described reasonably well by a straight line. Explanations for predator: non-predator relationships based on the dynamics of trophic interactions (e.g. competition for prey types or enemy-free space) seem insufficient to explain this pattern, because within beetle assemblages the necessary interactions are so few. Of other proposed determinants, those based on the relationship of local and regional species pools, on energetics, or on non-trophic factors seem the most plausible candidates for explaining proportionality amongst beetles. Much of the deviation from the overall pattern can be accounted for by sampling method and latitude. Temperate samples have a higher proportion of predatory species than tropical, whilst litter and pitfall trap samples have higher proportions of predatory species than Malaise trap and fogging samples.
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  • 40
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    Oecologia 92 (1992), S. 556-562 
    ISSN: 1432-1939
    Keywords: Herbivory ; Chemical defense ; Sequestration ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Chrysomela confluens produces a salicylaldehyde-based defensive secretion which is very effective against generalist predators and apparently produced at no cost. If no cost defenses are common, then one of the basic assumptions in the plant-herbivore literature, i.e. tradeoffs among defense, reproduction, and growth, must be reconsidered. We examined the effectiveness of this defense by exposing defended larvae and larvae whose secretion had been removed to a generalist predator. Larvae which had their secretions intact were attacked by only 7% of the ants which encountered them, and none of these larvae suffered serious damage. In contrast, those which had been “milked” of their secretions immediately prior to exposure were attacked in 48% of such encounters, and two-thirds of the larvae were killed. Larvae which had been milked 24 or 72 h before exposure, then allowed to regenerate their defenses, were attacked at rates indistinguishable from larvae that had not been milked. Thus regenerated defenses are just as effective as original defenses. We also tested the hypothesis that the cost of defense production and maintainence would be reflected in reductions in developmental rates and final adult mass and increases in leaf consumption rate. We found that larvae which were milked daily of their secretions manifested no measurable cost of recharging reservoirs. Milked larvae grew and fed at the same rates as their control sibs, and became adults of equal or slightly larger size. The liberation of glucose from salicin, a precursor present in leaves of salicaceous hosts, during the production of salicylaldehyde apparently provides enough of an energetic benefit to offset the cost of maintaining an effective defense. Consistent with this hypothesis, we did not find that milked larvae compensated for increased nutritional or salicin demands by increasing their feeding rates. Although this patterns is familiar to chemical ecologists it is generally unappreciated in the plant-herbivore literature. It is likely that many arthropod herbivore defensive systems come at little or no cost, given the intimacy of association between herbivores and their food plants. Sequestration of host plant defensive chemicals which eliminates the cost of synthesis is common in arthropods. The de novo synthesis of chemical defenses may be less costly than expected if it is integrated into other parts of an insects metabolism. Calculations based on the bond energies or molecular constitution of the compounds will not yield a complete perception of cost. Tests over the life of the herbivore, coupled with an understanding of the herbivore's metabolism, are necessary.
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  • 41
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    Oecologia 89 (1992), S. 229-235 
    ISSN: 1432-1939
    Keywords: Lepidoptera ; Digestion ; Larvae ; Mandible ; C4 grasses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cynodon dactylon (Poaceae) leaf pieces recovered from the frass of final-instar Paratrytone melane larvae (Lepidoptera: Hesperiidae) were composed of 14–22 percent crushed cells and 78–86 percent uncrushed cells, yet approximate digestibilities of soluble carbohydrates and protein averaged 78 and 88 percent, respectively. Therefore, nutrients from uncrushed cells were extracted by P. melane. The ability of P. melane and another leaf-snipping lepidopteran, Pseudaletia unipuncta (Noctuidae), to digest the contents of uncrushed bundle sheath and mesophyll cells in C. dactylon was examined with transmission electron microscopy. Organelles and plasma membranes were digested in the foreguts and midguts of both species. These findings suggest that nutrients in uncrushed leaf cells may be extracted through plasmodesmata and cell wall pores after membranes are digested. The generality of leaf-snipping, vis-a-vis leaf crushing, among larval Lepidoptera was assessed by surveying the mandible morphologies of 202 species. In 82 percent of the species surveyed only incisor regions were present. I conclude that leaf-snipping is a common mode of feeding among phytophagous Lepidoptera and that the digestion of cell contents is efficient despite the fact that few of the cells of ingested plant tissues are crushed.
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  • 42
    ISSN: 1573-1561
    Keywords: Lymantria dispar ; gypsy moth ; Lymantria mathura ; Lepidoptera ; Lymantriidae ; pheromone ; disparlure ; cis-7,8-epoxy-2-methyocta-decane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Pheromone traps baited with (+)-disparlure,cis-7,8-epoxy-2methyocta-decane, captured males ofLymantria dispar, L. monacha, andL. mathura in northeastern People's Republic of China.L. dispar responded to the addition of olefin to (+)-disparlure-baited traps in a negative doseresponse manner. Observations on site and seasonal capture ofL. dispar andL. mathura are discussed.
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  • 43
    ISSN: 1573-1561
    Keywords: Coleoptera ; Scolytidae ; Cleridae ; Trogositidae ; Pteromalidae ; Ips pini ; Dendroctonus brevicomis ; Enoclerus lecontei ; Enoclerus sphegeus ; Temnochila chlorodia ; Tomicobia tibialis ; ipsdienol ; lanierone ; aggregation pheromone ; kairomone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Five doses of lanierone (2-hydroxy-4,4,6-trimethyl-2,5-cyclohexadien-1-one) were tested with one dose of enantiomerically pure [99.4% (4R)-(−)] ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol) for activity as an aggregation pheromone ofIps pini (Say) in California. The response ofI. pini to 1 mg/day ipsdienol + 20 μg/day lanierone was significantly greater than the response to ipsdienol alone, but the response pattern did not demonstrate a clear dose-response relationship. The response to the highest dose of lanierone (2 mg/day) was significantly lower than the response to ipsdienol alone. Ipsdienol attracted significantly moreI. pini than a male-infested log. Lanierone did not alter the percentage of maleI. pini responding to ipsdienol alone. Neither sex ofI. pini orDendroctonus brevicomis LeConte from California produced detectable amounts of lanierone, but myrcene-aerated maleD. brevicomis produced 97.8%-(4S)-(+)-ipsdienol. The black-bellied clerid,Enoclerus lecontei (Wolcott) (Coleoptera: Cleridae) was attracted to lanierone when released with ipsdienol. Neither compound was attractive when released alone, proving synergism for the kairomone of this predator. Lanierone did not influence the response of the predatorsTemnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae) andEnoclerus sphegeus (F.) (Coleoptera: Cleridae), which were attracted to all treatments containing ipsdienol.Tomicobia tibialis Ashmead (Hymenoptera: Pteromalidae) responded in significantly greater numbers to the male-infested log than it did to ipsdienol or ipsdienol + 20 μg/day lanierone.
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  • 44
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Pyralidae ; sex pheromone ; (Z,E)-9,11,13-tetradecatrienal ; mimic ; (Z,E)-7,9,11-dodecatrienyl formate ; wind tunnel ; attractant ; electrophysiology ; receptor cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The behavioral and electrophysiological activity of a mimic [(Z,E)7,9,11-dodecatrienyl formate] of the major sex pheromone component [(Z,E) 9,11,13-tetradecatrienal] of carob moth was assessed. Wind-tunnel bioassays demonstrated that the formate was as effective as natural gland extracts, and significantly more effective than the trienal alone or than the trienal blended with two minor pheromone components, in evoking source contact. Dispensers containing the formate were as effective as trienal-containing blend lures in attracting males when placed at the same dosage in traps in date gardens. Single-cell recordings showed that at least two olfactory neurons, differentiated by spike amplitude, are located in the long trichoid hairs on male carob moth antennae. Dose-response relationships indicated that puffs from cartridges loaded with at least 0.1 μg of the formate or of the trienal were necessary to elicit spiking by either the small or the large-spiking cell within a sensillum. Cross-adaptation studies demonstrated that both compounds stimulated the same large-spiking cell. The frequencies of spikes evoked from the large cell when stimulated by emissions from 0.1-μg, 1-μg, or 10-μg cartridges of either the formate or the trienal were not significantly different, suggesting that the formate is an effective mimic of the trienal at the antennal receptor cell level.
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  • 45
    ISSN: 1573-1561
    Keywords: Host-plant selection ; Coleoptera ; Scolytidae ; Nitidulidae ; Rhizophagidae ; Calliphoridae ; Diptera ; semiochemical ; monoterpenes ; methanol ; ethanol ; propanol ; terpinolene ; α-pinene ; 3-carene ; verbenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Several Scandinavian forest insects,Hylurgops palliatus, Tomicus piniperda, andTrypodendron domesticum (Coleoptera: Scolytidae),Rhizophagus ferrugineus (Coleoptera: Rhizophagidae) andPollenia spp. (Diptera: Calliphoridae) were attracted to window traps baited with ethanol and placed on Scots pine trees (Pinus sylvestris) in May–June, 1986. Release of ethanol at increasing relative rates of 0, 0.01, 0.1 and 1.0 (800 mg/day) from the window traps on trees in 1987 causedH. palliatus, T. domesticum, andR. ferrugineus to be increasingly attracted, whileT. piniperda was equally attracted at both 0.1 and 1.0 rates. The attraction ofT. piniperda to ethanol was weak compared to attraction to a monoterpene mix, (±)-α-pinene, (+)-3-carene, terpinolene. The terpene mix plus ethanol was significantly more attractive toH. palliatus than ethanol alone, but terpenes significantly reduced the attraction ofT. domesticum to ethanol. Baiting of pipe traps with a series of short-chain alcohols (methanol to hexanol) each alone showed that ethanol was greatly preferred byH. palliatus, T. domesticum, andR. ferrugineus over alcohols of one more or one less carbon, while longer-chain alcohols were not attractive. However,Glischrochilus hortensis (Col.: Nitidulidae) was attracted only to propanol. A series of 10-fold increasing release rates of ethanol (0.0001-1.0, where 1.0=800 mg/day) with either a “low” or “high” release of the terpene mix had various effects on the sexes during their attraction to pipe traps and subsequent entering of holes. Release of (−)-verbenone at 0.25 mg/day had no significant effect onH. palliatus orR. ferrugineus attraction to ethanol, but the response ofT. domesticum to ethanol was reduced. Several theories on olfactory mechanisms of host selection byT. piniperda are integrated and placed in ecological perspective.
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  • 46
    ISSN: 1573-1561
    Keywords: Cotton ; Gossypium arboreum ; tobacco budworm ; Heliothis virescens ; Lepidoptera ; Noctuidae ; resistance ; allelochemicals ; flavonoids ; gossypetin 8-0-rhamnoside ; gossypetin 8-0-glucoside
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Asiatic cottons [Gossypium arboreum (L.)] have been investigated as a source of resistance to the tobacco budworm [Heliothis virescens (Fab.)] because their diversely colored petals have been presumed to contain various allelochemicals. However, we found that larvae fedG. arboreum squares (buds) grew about equally compared with those fed squares from commercialG. hirsutum lines. The best source of resistance was found in severalG. hirsutum double-haploid (DH) lines. In our investigation of allelochemicals, G.arboreum lines were found to contain much less gossypol in leaves, squares (buds), and petals thanG. hirsutum L. lines. Flavonoids were significantly higher inG. arboreum lines only in petals. Of 22G. arboreum lines from which squares were gathered and fed to tobacco budworm (TBW) larvae in the laboratory, larval growth was not significantly decreased on any, but larval survival was decreased on six. When the square flavonoids were isolated and incorporated in laboratory diets for the TBW, moderate toxicity was observed. However, the estimated toxicities were not greater than those of the same flavonoid isolates fromG. hirsutum lines. The most prevalent flavonoids, all previously found in G.arboreum plant tissues, were gossypetin 8-0-glucoside and gossypetin 8-0-rhamnoside, neither of which were present inG. hirsutum tissue. Quercetin 3-0-glucoside, quercetin-3′-0-glucoside, and quercetin 7-0-glucoside were also present in significant amounts in both species. Gossypetin 8-0-rhamnoside and gossypetin 8-0-glucoside were the most toxic flavonoids tested (the ED50% was estimated to be 0.007 and 0.024) and therefore may prove to be contributing factors of resistance to TBW feeding.
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  • 47
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    Journal of chemical ecology 18 (1992), S. 875-884 
    ISSN: 1573-1561
    Keywords: Aggregation pheromone ; olfactometer ; field trapping ; Coleoptera ; Chrysomelidae ; Phyllotreta cruciferae ; Brassica napus ; crucifer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Laboratory olfactometer bioassays and field trapping experiments showed that the flea beetle,Phyllotreta cruciferae (Goeze), was highly attracted by oilseed rape(Brassica napus L.) when flea beetles were on the plant. This attraction was mediated by a flea beetle-produced aggregation pheromone based upon: (1) Oilseed rape damaged mechanically, or byP. cruciferae, or by diamondback moth,Plutella xylostella (L.), did not attractP. cruciferae. (2) Contact with the plants or feeding was required for the production of aggregation pheromone because oilseed rape alone was not attractive when separated from flea beetles by a screen. (3) Equal numbers of males and females were attracted.
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  • 48
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    Journal of chemical ecology 18 (1992), S. 863-873 
    ISSN: 1573-1561
    Keywords: Coleoptera ; Chrysomelidae ; Alticinae ; Phyllotreta cruciferae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Trapping experiments were carried out near Winnipeg, Canada, in the spring of 1987 and 1988 to test attraction of crucifer-feeding flea beetles to volatile glucosinolate (GS) hydrolysis products released from glass vials. Nine isothiocyanates (IC) or mustard oils and three nitriles (CN) were tested. The pattern of attraction was the same for both flea beetle species,Phyllotreta cruciferae, andP. striolata. Captures in traps baited with allyl IC increased as release rates increased from 0.04 mg/day to 40 mg/day. The lowest rate that attracted large numbers of beetles was 4 mg/day; therefore this rate was used for further experiments. More beetles were captured in traps baited with allyl IC than with any other compound. In 1988 only, four IC in addition to allyl IC were attractive to both species; namely, benzyl IC, ethyl IC, and a mixture of ethyl and methyl 4-isothiocyanatobutyrate (ICB). When captures of the two species were pooled, 3-methylthiopropyl IC, methyl ICB, andn-butyl IC were also found to be significantly attractive. Nitriles were the least attractive compounds. The high release rates of mustard oils required to attract flea beetles indicate that fields ofBrassica crops would release sufficient quantities of IC to attract flea beetles from a distance but individual or small groups of plants normally would not. It is concluded thatBrassica varietal resistance to flea beetles is unlikely to be affected by manipulating IC release.
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  • 49
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    Journal of chemical ecology 18 (1992), S. 907-914 
    ISSN: 1573-1561
    Keywords: Tobacco budworm ; Heliothis virescens ; Lepidoptera ; Noctuidae ; cotton ; gossypium hirsutum ; oviposition ; attractant ; floral extracts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Mated and virgin female and virgin male tobacco budworm moths,Heliothis virescens (F.), responded via directed upwind flight in wind-tunnel bioassays to volatiles from floral extracts of cotton,Gossypium hirsutum L. Significantly more male and female moths landed on cloth dispensers treated with a methylene chloride extract of debracted flowers than on control dispensers treated only with methylene chloride. Only mated females landed in significant numbers on the dispensers treated with extract of cotton squares, flowers (including bracts), or flower petals. After landing, most of the moths examined the dispensers by probing with their antennae, proboscis, and/or ovipositor.
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  • 50
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    Journal of chemical ecology 18 (1992), S. 1009-1024 
    ISSN: 1573-1561
    Keywords: Pieris rapae ; Artogeia rapae ; Trichoplusia ni ; Lepidoptera ; Noctuidae ; Pieridae ; trypsin inhibitors ; chymotrypsin inhibitors ; serine proteinase inhibitors ; cabbage ; Cruciferae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Trypsin and chymotrypsin inhibitors are proteins that are developmentally regulated in foliage of cabbage plants, appearing at high concentrations in young foliage on mature plants. This temporal and spacial regulation of foliar proteinase inhibitors is synchronized with the appearance and distribution of foliar feeding Lepidoptera. When insects were allowed to select their feeding sites, larvalPieris rapae fed on the young foliage of cabbage plants, while larvalTrichoplusia ni fed on the mature foliage on cabbage plants. LarvalP. rapae that fed on mature plants were significantly smaller than larvae feeding on young plants, while there was no significant difference between larvalT. ni feeding on mature plants and those feeding on young plants. Thus, there was a significant inverse correlation between the level of proteinase inhibitory activity in cabbage foliage and larval growth. WhenP. rapae andT. ni were provided with an artificial diet containing total protein (including significant levels of proteinase inhibitors) that was extracted from cabbage foliage, there was a significant reduction in growth and development of both species of Lepidoptera.
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  • 51
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Pyralidae ; Gallerinae ; Galleria mellonella ; greater wax moth ; sex pheromone gland ; nonanoic acid ; undecanoic acid ; 1-nonanol ; 1-undecanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Chemical analyses of pheromone-gland extracts and volatiles released by maleGalleria mellonella (L.), the greater wax moth, resulted in the identification and quantification of the aldehydes, primary alcohols, and fatty acids of nonane and undecane. Adult females released none of these six compounds. Mean percentages of the aldehydes and alcohols in the gland extracts were 19.0% undecanal, 3.9% nonanal, 48.3% 1-undecanol, and 28.8% 1-nonanol. Mean percentages of the aldehydes and alcohols in volatiles collected during the first hour of scotophase from moths 1 to 9 days old were 77.4% undecanal, 20.8% nonanal, 1.46% 1-undecanol, and 0.36% 1-nonanol. Age did not significantly affect the amount of each compound collected. The collection of volatiles from moths 3 to 5 days old during a 12-hr scotophase indicated that production was greatest during the first and third quarters of the period. Methylation of group volatile samples allowed the quantification of the fatty acids.
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  • 52
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    Journal of chemical ecology 18 (1992), S. 1577-1582 
    ISSN: 1573-1561
    Keywords: Coleoptera ; Scolytidae ; Ips latidens ; Ips pini ; interspecific communication ; synomone ; pheromone ; ipsenol ; ipsdienol ; chirality ; enantiospecificity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In south-central British Columbia, the attraction ofIps latidens (LeConte) to its pheromone, ipsenol, was inhibited by (S)−(+)-ipsdienol, a pheromone forI. pini (Say). (R)-(−)−lpsdienol had no effect onI. latidens. (S)−(+)-lpsdienol probably plays a role in interspecific communication between the two species, facilitating reductions in interspecific competition for breeding material and/or interspecific mating interference.
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  • 53
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    Journal of chemical ecology 18 (1992), S. 1623-1632 
    ISSN: 1573-1561
    Keywords: Oak wilt ; Ceratocystis fagacearum ; headspace volatiles ; Coleoptera ; Nitidulidae ; Carpophilus hemipterus ; Carpophilus lugubris ; Stelidota geminata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ceratocystis fagacearum (Bretz) Hunt is the causative agent of oak wilt disease, which is transmitted primarily by nitidulid beetles. This fungus was compared with four non-insect-dependent fungi for their volatile profiles using gas chromatography and mass spectrometry (GC-MS) and for their attractiveness to nitidulids using a wind-tunnel bioassay. The four additional fungi includedXerula radicata Sing,Pluteus atricapillus Kumm,Tyromyces chioneus Karst, andBotrytis cinerea. Nitidulids have been reported in association with each of these fungi, but unlikeC. fagacearum, they are dispersed primarily by wind or rain. Significant attraction of three nitidulid species,Carpophilus hemipterus (Linne),C. lugubris Murray, andStelidota geminata (Say) was elicited byC. fagacearum and to a lesser extent byX. radicata, but not by the others. A comparison of headspace volatile profiles showed that the odor ofC. fagacearum was the strongest, both with regard to the number of components and in their rates of production. Chemical characterization of the headspace profile ofC. fagacearum revealed 16 components: one aldehyde, one ketone, five alcohols, and nine esters. These components were all common fruit-odor constituents and many of them were previously shown to be attractive to nitidulid beetles. The results of this study suggest that, by mimicking food odors,C. fagacearum odor is an adaptation for attracting nitidulid and possibly other insect vectors.
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  • 54
    ISSN: 1573-1561
    Keywords: Pheromone identification ; (6Z,9Z)-6,9-cis-3,4-epoxyhepta-decadiene ; (3Z,6Z,9Z)-3,6,9-heptadecatriene ; Abraxas grossulariata ; Lepidoptera ; Geometridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (3Z,6Z,9Z)-3,6,9-Heptadecatriene and (6Z,9Z)-6,9-cis-3,4-epoxyheptadecadiene have been identified in female sex pheromone gland extracts ofAbraxas grossulariata L. (Lepidoptera: Geometridae). The compounds were detected by gas chromatography with electroantennographic detection (GC-EAD) and identified by GC-mass spectrometry (GC-MS). The amounts of hydrocarbon and epoxide were 0.13 and 0.42 ng/female, respectively. These identifications were confirmed by synthesis; the absolute configuration of the epoxide remains to be determined. Another isomeric epoxide, (3Z,6Z)-3,6-cis-9,10-epoxyheptadecadiene, was tentatively identified in small amounts (0.04 ng/female). Racemic (6Z,9Z)-6,9-cis-3,4-epoxyheptadecadiene elicited the largest electroantennogram response within a series of heptadecadiene and nonadecadiene monoepoxides and the corresponding trienic hydrocarbons and, in field tests, attracted maleA. grossulariata into traps. Addition of 10% (3Z,6Z,9Z)-3,6,9-heptadecatriene to this epoxide enhanced attractiveness; addition of (3Z,6Z)-3,6-cis-9,10-epoxyheptadecadiene had no effect at low proportions while higher proportions caused a reduction in the numbers of males caught.
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  • 55
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    Journal of chemical ecology 18 (1992), S. 1901-1912 
    ISSN: 1573-1561
    Keywords: Parasitoid ; pheromone ; bioassay ; wind-tunnel ; Hymenoptera ; Braconidae ; Macrocentrus grandii ; Lepidoptera ; Pyralidae ; Ostrinia nubil-alis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A multicomponent sex pheromone inMacrocentms grandii Goidanich (Hymenoptera: Braconidae) was demonstrated using wind-tunnel and field bioassays. In wind-tunnel bioassays, three Florisii fractions from female wasps (hexane, 5%, and 50% ether in hexane) and one from male wasps (50% ether in hexane) were attractive to males. The hexane and 5% ether in hexane fractions each elicited similar male behavioral responses. These included upwind anemotaxis, casting, landing on the source, wing fanning, and mating attempts between males. The 50% ether in hexane fraction, whether male- or female-derived, initiated a strong flight response by males but few landings on the source. In addition, the 50% ether in hexane fraction was found to synergize strongly the hexane fraction. All females tested in the wind tunnel gave no responses to male- or female-derived extracts. Field tests generally supported the wind-tunnel results, although no field attraction was observed for the 5% ether in hexane fraction.
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  • 56
    ISSN: 1573-1561
    Keywords: Boarmia selenaria ; giant looper ; sex pheromones ; Lepidoptera ; Geometridae ; (Z,Z)-6,9-cis-(3S,4R)-epoxynonadecadiene ; (Z,Z)-6,9-cis-(3R,4S)-epoxynonadecadiene ; (Z,Z,Z)-3,6,9-nonadecatriene, anantiomers ; enantioselective synthesis ; EAG ; wind tunnel ; field tests ; precursor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (Z,Z)-6,9-cis-(3S,4R)-Epoxynonadecadiene9a and (Z,Z,Z)-3,6,9-nonadecatriene have been identified as sex pheromone components in female ovipositor extracts and effluvia of the geometridBoarmia selenaria. The identification was based on relative retention times on gas chromatographic columns, GC-MS, chemical enantioselective syntheses, EAG, wind-tunnel behavioral experiments, and field tests. A single female ovipositor extract contained an average of 42 ng of (Z,Z)-6,9-cis-3,4-epoxynonadecadiene and 2 ng of (Z,Z,Z)-3,6,9-nonadecatriene.EAG, wind-tunnel behavioral studies, and field tests demonstrated that maleB. selenaria exhibit preferential attraction for the (3S,4R)-enantiomer of (Z,Z)-6,9-cis-3,4-epoxynonadecadiene. Only in effluvia and ovipositor extracts of calling females was (Z,Z)-6,9-cis- 3,4-epoxynonadecadiene detected, whereas relatively high amounts of (Z,Z,Z)-3,6,9-nonadecatriene were found in noncalling females. Wind-tunnel behavioral studies showed that (Z,Z,Z)-3,6,9-nonadecatriene did not elicit any response in the males, and when tested in combination with a mixture of monoepoxynonadecadienes, (Z,Z,Z)-3,6,9-nonadecatriene decreased the observed behavioral responses. A possible precursor role for (Z,Z,Z)-3,6,9-nonadecatriene in the pheromonal system is discussed.
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  • 57
    ISSN: 1573-1561
    Keywords: Natural attractant ; pheromone ; Migdolus fryanus ; Coleoptera ; Cerambycidade ; male response ; sugarcane pest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Migdolus fryanus is a sugarcane pest restricted to South America that is becoming more important due to the inefficacy of control methods against it. The larvae bore into the plant root system and the available insecticides can not give adequate protection. So, the search for alternate control strategies is mandatory. However, the literature on bioethological studies of the species is scarce. This work investigates the attraction of adult males in the field by females that is mediated by a sex pheromone that remains to be identified. Dissected female thoraces were more attractive than other body parts. A trap design for monitoring field populations of this species also is presented.
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  • 58
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    Journal of chemical ecology 18 (1992), S. 283-298 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Pyralidae ; Ostrinia nubilalis ; European corn borer ; tritiated pheromone ; 11-tetradecenyl acetate ; sensory biochemistry ; catabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Isomers of [11,12-3H2]-11-tetradecenyl acetate (57 Ci/mM) were synthesized. Behavioral assay of the two compounds using Z- and E-type European corn borer (ECB) males showed that introduction of tritons into the double bond of the pheromone caused a significant isotope effect in the E-type ECB but not in the Z-type ECB. Measurements of tritium associated with the male antennae after a 3-min exposure showed that radioactivity equivalent to 10−7 mol pheromone was adsorbed onto male antennae. Time-course in vivo metabolic studies with picogram amounts of compound applied topically to antennae of E- and Z-type males and Z-type females showed that they metabolized pheromone similarly but females degraded pheromone more slowly than males. Pheromone was hydrolyzed, and the only other major radiolabeled metabolite observed by combined high-pressure liquid chromatography-radiodetection was tritiated water. Capillary gas chromatography and radiomonitoring permitted detection of a trace amount of 11-tetradecenoic acid, which indicated alcohol oxidase activity is associated with the antennae. Evidence shows that clearing of pheromone from the ECB male antennae involves hydrolysis and oxidation of the alcohol to fatty acid, which in turn is degraded, probably via β-oxidation, to carbon dioxide and water.
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  • 59
    ISSN: 1573-1561
    Keywords: Pheromone ; aggregation ; hydrocarbon ; tetraene ; triene ; NMR ; mass spectra ; dried-fruit beetle ; Carpophilus hemipterus ; Coleoptera ; Nitidulidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Males ofCarpophilus hemipterus (L.), the dried-fruit beetle, (Coleoptera: Nitidulidae) were found to emit nine all-E tetraene and one all-E triene hydrocarbons in addition to two pheromonally active tetraenes that had been reported previously. The previously known compounds are (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene(1) and (2E,4E,6E,8E)-3, 5,7-trimethyl-2,4,6,8-undecatetraene(2). The new tetraenes were all related to structure1 by having one additional carbon at either one or two of the following four locations: at carbon 1 of the chain, at carbon 10 of the chain, at the 5-alkyl branch, or at the 7-alkyl branch. (Structure 2 also fits within this pattern.) The triene inC. hemipterus is (2E,4E,6E)-5-ethyl-3-methyl-2, 4,6-nonatriene. Also identified from volatile collections from the beetles were the 2Z and 4Z isomers of1. All structures were proven by synthesis, with NMR and mass spectral data for the compounds provided. Two of the newly discovered compounds, (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-decatetraene and (2E,4E,6E,8E)-7-ethyl-3,5-dimethyl-2,4,6,8-undecatetraene, were quite active in the wind-tunnel bioassay, but others, such as (2E,4E,6E,8E)-5-ethyl-3,7-dimethyl-2,4,6,8-decatetraene and (2E,4E,6E,8E)-4,6,8-trimethyl-2,4,6,8-undecatetraene were not. Structureactivity relationships are explored among the natural compounds and additional, synthetic analogs, which were never detected from the beetles. Some of these analogs, such as (2E,4E,6E,8E)-3,5-dimethyl-7-propyl-2,4,6,8-undecatetraene, were quite active in the bioassay. The biosynthesis of the beetle-derived compounds is discussed. A single biosynthetic scheme that lacks complete enzyme specificity at four specific steps could account for the entire series of compounds found in the beetles and their relative proportions. The definition of “pheromone” is discussed in relation to these hydrocarbons.
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  • 60
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    Journal of chemical ecology 18 (1992), S. 1227-1237 
    ISSN: 1573-1561
    Keywords: Western corn rootworm ; Diabrotica virgifera virgifera ; Coleoptera ; Chrysomelidae ; bacteria ; carbon dioxide ; pheromone ; semiochemicals ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract FemaleDiabrotica virgifera virgifera LeConte were allowed to choose between oviposition substrates that were and those that were not associated with potential sources of semiochemicals. Females deposited over five times more eggs on moist towelettes that were treated with homogenates of female abdomens than on towelettes treated with distilled water. Similar results were obtained when screening separated the homogenates from the towelettes, indicating that odors alone could elicit the response. In contrast, females did not choose towelettes that had previously been used for oviposition or towelettes containing eggs over unused towelettes. Further tests with homogenates of abdomens and a bacteriostatic agent (sorbate) indicated that the females were probably responding to bacterial odors rather than an oviposition-enhancing pheromone. Four strains of bacteria were isolated from a homogenate of female abdomens; females deposited 4 to 16 times more eggs on substrates with odors of the bacteria than on substrates with odors of uninoculated nutrient agar. In no-choice tests, bacterial odors did not increase the number of eggs deposited per female beetle; however, in choice tests with dishes that tended to retain any beetles that entered, there were more eggs per female (but not more beetles) after 24 hr in dishes with bacterial odors than in those without the odors. Females also chose dishes with odors of excised maize (Zea mays L.) roots or elevated levels of carbon dioxide over “control” dishes.
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  • 61
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    Journal of chemical ecology 18 (1992), S. 1375-1387 
    ISSN: 1573-1561
    Keywords: Oreina gloriosa ; Coleoptera ; Chrysomelidae ; chemical defense ; allomone ; cardenolides ; quantitative variation ; heritability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Defensive secretions of adultOreina gloriosa, liberated at the surface of the pronotum and elytra, contain a complex mixture of cardenolides, and ethanolamine. Proportions and concentrations of constituents determined by reverse-phase HPLC show considerable variation among individual beetles. Heritabilities of proportions of five main components were estimated by mother-offspring regression providing a validation of the less reliable full-sib correlation estimates. Average heritabilities based on the two methods were 0.51 and 0.58, respectively, estimated by using offspring of two age groups. Regression estimates of 2- and 10-week-old offspring differed significantly for one secretion constituent (RT16). Heritability estimates of concentrations of 16 secretion components were calculated by full-sib correlation analysis. Average heritability was 0.45, indicating a significant genetic component. Estimates did not differ significantly between the two age groups. We also estimated heritabilities of concentrations by a two-way model including data from offspring of both age groups. Heritability estimates based on this model are thought to correspond approximately to estimates based on samples from natural populations. The average of these estimates was lower (h 2 =0.31) than the average heritability of each age group separately (h 2 =0.45), suggesting a developmental effect on variation in chemical defense ofO. gloriosa.
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  • 62
    ISSN: 1573-9171
    Keywords: EPR ; radical ; fluorine ; conformation ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract EPR spectra of radical adducts of phosphonyl radicals with 2-hydroperfluoro-4-methyl- and 4,4-dimethyl-2-pentene have been studied. The molecular mechanics method has been used to determine the preferred conformation of the (CF3)2CF-CF-HCF3P(O)(OMe)2 radical. The eclipsed conformation of the C–P bond and 2p z -orbital of an unpaired electron is stabilized due to steric factor and hyperconjugation.
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  • 63
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    Plant and soil 142 (1992), S. 157-166 
    ISSN: 1573-5036
    Keywords: Acacia ; Eucalyptus regnans ; decomposition ; litterfall ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The N and P contents of the litter layer and the return of these nutrients in litterfall were measured in seven stands of Mountain Ash (Eucalyptus regnans) ranging in age from 5 years to about 250 years. Both annual litterfall and nutrient return were correlated with stand basal area and were high compared with other productive eucalypt forests. In contrast, the fall of dead eucalypt leaves was constant with stand age, demonstrating that sites are fully occupied at an early age. Similarly, amounts of N and P in total leaf fall (overstorey plus understorey) were constant with stand age, except for low amounts in the stand aged 40 years where Acacia spp., important fixers of atmospheric N, were not prevalent. The decomposition constant (k) of organic matter in the litter layer decreased with stand age, from 0.31 year-1 at age 5 years to 0.23 year-1 at age 250 years. These constants also applied to N and P, indicating a tight coupling between organic matter decomposition and release of these nutrients from litter. The litter layer released about 30 kg ha-1 of N at age 5 years, and about 70 kg ha-1 at age 80 years. These results are discussed in relation to growth of Mountain Ash following fire, and the subsequent retention and accumulation of N during stand development.
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  • 64
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    Plant and soil 145 (1992), S. 45-50 
    ISSN: 1573-5036
    Keywords: acidity ; manganese ; pH ; phosphorus ; soil solution wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot experiment was carried out in order to test the hypothesis that manganese nutrition of wheat was dependent on the phosphorus status of soil as well as on its pH and manganese status. An arable mineral soil whose lime and phosphorus status had been massively adjusted more than 18 years previously was compared with identical soil not so adjusted. Wheat plants were grown to maturity in these soils. Analyses were carried out on both soil and plant samples at intervals. Data for soil pH, soil solution concentrations of manganese and phosphorus, plant dry weight and tissue concentrations of manganese and phosphorus are presented. Concentrations of manganese were depressed in leaf tissue of plants from limed soils and also in high phosphorus soils. The depressed values for limed treatments were explained in terms of depressed soil solution manganese concentrations resulting from elevated pH. The results for high phosphorus soils could not be related to soil solution composition. It was suggested that high soil phosphorus resulted in elevated plant phosphorus which interfered in the uptake and/or translocation of manganese.
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  • 65
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    Plant and soil 146 (1992), S. 163-168 
    ISSN: 1573-5036
    Keywords: genetic variability ; NIR ; ploidy ; phosphorus ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract More efficient utilization of phosphorus by wheat plants is needed to extend the useful life of the phosphate reserves in the world, to reduce the cost of producing crops, and to improve the value of the grain and the straw produced. In this paper definitions of efficient use of phosphorus by wheat are reviewed, genotypic variation in phosphorus efficiency is reported, some consequences of breeding for greater efficiency are discussed, and ways to select more efficient genotypes are suggested.
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  • 66
    ISSN: 1573-5036
    Keywords: critical concentration ; deficiency ; diagnosis ; growth rate ; lettuce ; luxury consumption ; nitrogen ; nitrate ; nutrient requirement ; petiole sap ; phosphorus ; phosphate ; potassium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A method is described for determining the way in which growth rate varies with plant nutrient concentration using a simple nutrient interruption technique incorporating only 2 treatments. The method involves measuring the changes in growth and nutrient composition of otherwise well-nourished plants after the supply of one particular nutrient has been withheld. Critical concentrations are estimated from the relationship between the growth rate (expressed as a fraction of that for control plants of the same size which remained well-nourished throughout) and the concentration of the growth-limiting nutrient in the plants as deficiency developed. Trials of the method using young lettuce plants showed that shoot growth rate was directly proportional to total N (nitrate plus organic N) concentration, and linearly or near-linearly related to K and P concentration over a wide range; the corresponding relationship for nitrate was strongly curvi-linear. Critical concentrations (corresponding to a 10% reduction in growth rate) determined from these results were similar to critical values calculated from models derived from field data, but were generally higher than published estimates of critical concentration (based on reductions in shoot weight) for plants of a similar size. Reasons for these discrepancies are discussed. Nitrate, phosphate or potassium concentrations in sap from individual leaf petioles were highly sensitive to changes in shoot growth rate as deficiency developed, with the slope of the relationships varying with leaf position, due to differences both in their initial concentration and in the rates at which they were utilized in individual leaves. Each nutrient was always depleted more quickly in younger leaves than in older ones, providing earlier evidence of deficiency for diagnostic purposes. Although the plants were capable of accumulating nitrate, phosphate and potassium well in excess of that needed for optimum dry matter production during periods of adequate supply, the rate of mobilization of these reserves was insufficient to prevent reductions in growth rate as the plants became deficient. This brings into question the validity of the conventional concept that luxury consumption provides a store of nutrients which are freely available for use in times of shortage. The implications of these results for the use of plant analysis for assessing plant nutrient status are discussed.
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  • 67
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    Plant and soil 145 (1992), S. 65-70 
    ISSN: 1573-5036
    Keywords: calcifuge plants ; phosphorus ; deficient absorption ; Deschampsia flexuosa ; Jasione montana ; Rumex acetosella ; Silene rupestris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Germination, seedling establishment and growth of calcifuge plants in Swedish limestone soils of Archean and Ordovician age were studied. As previously demonstrated for Viscaria vulgaris, establishment of Rumex acetosella and Silene rupestris did not succeed unless CaHPO4 (at the rate of 10 mmol dm-3 of soil) was supplied. Growth of Deschampsia flexuosa was enhanced by phosphate addition, whereas establishment success of Jasione montana was poor, regardless of phosphate treatment. Establishment and growth in an acidic gneiss soil, used as a reference for the species studied, was good. Total, total inorganic, exchangeable, and soil solution P were considered in all soils and treatments. It is proposed that the calcifuge behaviour of plants is quite often caused by inability to solubilize the native phosphate of limestone soils.
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  • 68
    ISSN: 1573-5036
    Keywords: cultivars ; grains ; maize ; nitrogen ; phosphorus ; potassium ; tropical climate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An earlier study revealed considerable genotypic variation in grain N, P and K concentrations (GNC, GPC and GKC, respectively) in tropical maize. The expression of varietal differences in GNC, GPC and GKC, however, may depend on environmental conditions such as the N status of the soil. Two tropical maize hybrids (Suwan 2301 and CP 1) with comparable yielding capacity, but contrasting GNCs, GPCs and GKCs, were therefore grown at four levels of N in a field experiment at Farm Suwan (Thailand, latitude 14.5°N). Suwan 2301 exhibited a higher GNC than did CP 1 at all rates of N, but large differences in GPC and GKC were found only at high N fertilization. This was obviously due to individual grain yield responses of the cultivars to increasing rates of N fertilizer, demonstrating that grain nutrient concentrations are, at least in part, functions of the amount of grain carbohydrates which dilute a genetically and environmentally fixed amount of grain P and K. As compared to Suwan 2301, CP 1 accumulated less N, P and K in the grains at almost all levels of N fertilization, confirming our hypothesis that the cultivation of maize genotypes with low grain mineral nutrient concentrations may help third-world cash-crop farmers to reduce the need for scarce and costly mineral fertilizers. This finding has to be verified at reduced availability of soil −P, −K, and water.
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  • 69
    ISSN: 1573-5117
    Keywords: River Rhine ; phytoplankton ; suspended material ; carbon ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial and temporal distribution of element concentrations were monitored together with chlorophyll a as an indicator of algal density to assess the effect of phytoplankton on the elemental composition (C, N, P) of suspended materials in the lower Rhine. The high concentrations of particulate C, N and P in the river were found to decrease in the delta and to increase again in the estuarine turbidity zone. Phytoplankton blooms increased the concentrations of particulate C, N, and P significantly in the upstream part of the river. In summer 1989, 15–65% of the particulate C and 20–75% of the particulate N were attributable to phytoplankton. Together with published data these observations indicate that in eutrophic rivers, the input of organic materials from the catchment is strongly modified and supplemented by in situ growth of phytoplankton. During seaward transport the phytoplankton and the particulate elements disappeared from the river water concomitantly with the suspended matter, indicating an increased retention of these elements due to sedimentation. In contrast, soluble ammonia, nitrite and phosphate increased in the tidal reaches of the river because of local input in the harbour and city of Rotterdam and because of mineralization. Therefore the total nutrient load of the Rhine estimated at the German/Dutch border does not reflect the actual input into the sea.
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  • 70
    ISSN: 1573-5117
    Keywords: Lakes ; sediments ; iron ; phosphorus ; phosphate release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis of Danish lakes showed that both mean winter and mean summer concentrations of lake water total phosphorus in the trophogenic zone correlated negatively with the total iron to total phosphorus ratio (Fe:P) in surface sediments. No correlation was found between the water total phosphorus concentration and either the sediment phosphorus concentration alone or with sediment calcium concentration. The increase in total phosphorus from winter to summer, which is partly a function of net internal P-loading, was lowest in lakes with high Fe:P ratios in the surface sediment. A study of aerobic sediments from fifteen lakes, selected as representative of Danish lakes with respect to the sediment Fe and phosphorus content, showed that the release of soluble reactive phosphorus was negatively correlated with the surface sediment Fe:P ratio. Analysis of phosphate adsorption properties of surface sediment from 12 lakes revealed that the capability of aerobic sediments to buffer phosphate concentration correlated with the Fe:P ratio while the maximum adsorption capacity correlated with total iron. Thus, the Fe:P ratio may provide a measure of free sorption sites for orthophosphate ions on iron hydroxyoxide surfaces. The results indicate that provided the Fe:P ratio is above 15 (by weight) it may be possible to control internal P-loading by keeping the surface sediment oxidized. Since the Fe:P ratio is easy to measure, it may be a useful tool in the management of shallow lakes.
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  • 71
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    Hydrobiologia 240 (1992), S. 45-59 
    ISSN: 1573-5117
    Keywords: arctic lakes ; trace metals ; lake sediments ; manganese ; iron ; phosphorus ; sediment-water flux ; diagenesis ; Toolik Lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sediments within Toolik Lake in arctic Alaska are characterized by extremely low rates of organic matter sedimentation and unusually high concentrations of iron and manganese. Pore water and solid phase measurements of iron, manganese, trace metals, carbon, nitrogen, phosphorus, and sulfur are consistent with the hypothesis that the reduction of organic matter by iron and manganese is the most important biogeochemical reaction within the sediment. Very low rates of dissolved oxygen consumption by the sediments result in an oxidizing environment at the sediment-water interface. This results in high retention of upwardly-diffusing iron and manganese and the formation of metal-enriched sediment. Phosphate in sediment pore waters is strongly adsorbed by the metal-enriched phases. Consequently, fluxes of phosphorus from the sediments to overlying waters are very small and contribute to the oligotrophic nature of the Toolik Lake aquatic system. Toolik Lake contains an unusual type of lacustrine sediment, and in many ways the sediments are similar to those found in oligotrophic oceanic environments.
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  • 72
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    Hydrobiologia 229 (1992), S. 23-41 
    ISSN: 1573-5117
    Keywords: TOC ; COD ; humic ; colour ; Secchi ; phosphorus ; carbon ; permanganate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 18 Swedish forest lakes covering a wide range of dystrophy were studied in order to quantify and characterize the organic matter in the water with respect to origin (allochthonous or autochthonous), physical state (particulate or dissolved) and phosphorus content. Samples were collected repeatedly during a two-year period with unusually variable hydrological conditions. Water from three different depths and from tributaries was analysed with standard monitoring methods, including water colour, Secchi disk transparency, total organic carbon (TOC), CODCr, CODMn, total phosphorus and molybdate reactive phosphorus. Interrelationships were used to compare different methods and to assess the concentration and composition of organic matter. It is estimated that in remote softwater lakes of the Swedish forest region, autochthonous carbon is typically 〈 5 g m−3. Most lakes in this region receive significant amounts of humic matter originating from coniferous forest soils or peatland in the catchment area. In most humic lakes with a water colour of ≥ 50 g Pt m−3, more than half of the organic carbon in the surface water is of allochthonous origin, and in polyhumic lakes (〉 200 g Pt m−3) the proportion can exceed 90%. Secchi depth readings were related similarly to organic matter from both sources and provided good estimates of TOC with a single optical measurement. Water colour was used to distinguish allochthonous and autochthonous matter. High concentrations of phosphorus were found in humic waters, most of it being molybdate reactive, and probably associated with humic matter rather than as dissolved free inorganic forms. CODMn yielded only 25–60% of TOC and appears to include mainly truly dissolved substances of low molecular weight.
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  • 73
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    Hydrobiologia 230 (1992), S. 193-200 
    ISSN: 1573-5117
    Keywords: nitrogen ; phosphorus ; ricefield system ; drainage channels ; mediterranean Deltas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogen and phosphorus released into the water of a main drainage channel in the Ebro Delta was measured during a period of rice cultivation. An increase in total nitrogen and phosphorus in its different forms in accordance with the increase in cultivated area drained was observed. A significant correlation between the release of nutrients into the water and the nutrient load, for both nitrogen and phosphorus, if we consider the release of nutrients per unit of length of the channel and increased total phosphorus content of the water that flows through it during the period of rice cultivation. Physical and chemical changes in the water as a result of ricefield metabolism may explain the differences observed in nitrogen and phosphorus cycles between Ebro and Rhône Deltas, two mediterranean deltaic systems where a large area with similar drainage system is used for rice cultivation.
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  • 74
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    Hydrobiologia 243-244 (1992), S. 395-403 
    ISSN: 1573-5117
    Keywords: Lake Päijänne ; pulp mills ; BOD ; phosphorus ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Päijänne, the second largest lake in Finland, has been seriously polluted since the 1960s due to the effluents from pulp and paper mills, notably the Äänekoski sulphate and sulphite pulp mills situated about 50 km north of the lake, and the sulphite pulp mill and paper mills of Jämsänkoski and Kaipola on Central Lake Päijänne. A sulphite lye evaporation and combustion plant installed at the Jämsänkoski sulphite pulp mill in 1969 reduced the organic pollution of Central Päijänne. Lignin concentration decreased and the oxygen balance improved. The sulphite pulp mill was closed in 1981 and replaced by a thermo-mechanical pulp mill. Eutrophication is the main threat to water quality in Central Lake Päijänne at present. A significant improvement in the water quality, especially in oxygen balance, was achieved in the watercourse of Äänekoski and in Northern Päijänne after replacement of the old sulphite and sulphate pulp mills at Äänekoski by a large sulphate pulp mill with a biological purification plant employing the activated sludge method. The BOD7-loading dropped from 46 to 3–4 t d−1, but the nutrient loading has not decreased sufficiently, and the Äänekoski watercourse and Northern Päijänne are still eutrophic.
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  • 75
    ISSN: 1573-5117
    Keywords: acid lakes ; ATP ; in situ enclosures ; liming ; phosphatases ; phosphorus ; phytoplankton community
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A bioassay was developed, involving steady-state ATP level determinations, for estimation of phosphate demand and deficiency in natural phytoplankton communities. The studies were performed on phytoplankton from the moderately acidified Lake Njupfatet in central Sweden before and after liming. Phytoplankton samples from in situ enclosure experiments with low-dose enrichments of nitrate and phosphate and removal of large (〉 100 µm) zooplankton and from the lake water were collected. The phytoplankton were concentrated by through-flow centrifugation and post-cultured in the laboratory with or without the addition of phosphate. A relative increase in the ATP:chlorophyll a ratio after the phosphate treatment as compared to samples without phosphate enrichment was found to be a highly reproducible indicator of phosphate deficiency in the natural phytoplankton population. In contrast, the absolute ATP:chlorophyll a ratio varied substantially between different sampling occasions. No phosphate deficiency was detected in phytoplankton from the acidic lake or from fertilized in situ enclosures. However, phytoplankton from in situ enclosures without added nutrients showed evidence of phosphate limitation after 21 days incubation. Also, the phytoplankton community developed a significant phosphate deficiency the summer after lake liming. The results from the ATP analyses are compared with chemical data of the lake water, phytoplankton community structure and phosphatase activities in the lake before and after liming. The average total biomass of phytoplankton and the average Tot-P measured during May to September decreased with appr. 30% after liming while Tot-N was essentially unaffected and the phosphatase activities increased by 1000–2000%.
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  • 76
    ISSN: 1573-5117
    Keywords: nutrient regeneration ; phosphorus ; nitrogen ; sediment ; lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mineralization of phosphorus and nitrogen from seston was studied in consolidated sediment from the shallow Lake Arreskov (July and November) and in suspensions without sediment (July). In the suspension experiment, phosphorus and nitrogen were mineralized in the same proportions as they occurred in the seston. During the 30 days suspension experiment, 47 and 43% of the particulate phosphorus and nitrogen, respectively, was mineralized with constant rates. Addition of seston to the sediment had an immediate enhancing effect on oxygen uptake, phosphate and ammonia release, whereas nitrate release decreased due to denitrification. The enhanced rates lasted for 2–5 weeks, while the decrease in nitrate release persisted throughout the experiment. The increase in oxygen uptake (equivalent to 21% of the seston carbon) was, however, only observed in the July experiment. The release of phosphorus and nitrogen from seston decomposing on the sediment surface differed from the suspension experiments. Thus, between 91 and 111% of the phosphorus in the seston was released during the experiments. Due to opposite directed effects on ammonium and nitrate release, the resulting net release of nitrogen was relatively low. A comparison of C/N/P ratios in seston, sediment and flux rates indicated that nitrogen was mineralized faster than phosphorus and carbon. Some of this nitrogen was lost through denitrification and therefore not measurable in the flux of inorganic nitrogen ions. This investigation also suggests that decomposition of newly settled organic matter in sediments have indirect effects on sediment-water exchanges (e.g. by changing of redox potentials and stimulation of denitrification) that modifies the release of mineralized phosphate and nitrogen from the sediment.
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  • 77
    ISSN: 1573-5117
    Keywords: eutrophication ; lake restoration ; flushing ; Veluwemeer ; algal species ; transparency ; phosphorus ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Total phosphorus and chlorophyll decreased significantly after reduction of the external phosphorus loading and the start of flushing Veluwemeer with polder water in 1979. Flushing of Veluwemeer has had a large impact on nutrient dynamics. Especially in the first winter, dilution was the main cause of changes in water quality. On a longer term the increase of the inactivation of phosphorus in sediments is important. Oscillatoria agardhii has been brought to the margins of its habitat. Three successive cold winters were an additional causal factor in the disappearance of Oscillatoria agardhii and the dominance of diatoms and green algae from 1985 onwards. Due to higher detritus and inorganic suspended matter concentrations transparency increased less than expected. Since 1985 chlorophyll only contributes for a small percentage to the transparency. In the present situation further improvement of the water quality of Veluwemeer is questionable, as the phosphorus concentration in the lake and the polder water is almost the same. Therefore it is recommanded to shift flushing operations, at least in the winter period, from Veluwemeer towards Wolderwijd.
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  • 78
    ISSN: 1573-5117
    Keywords: eutrophication ; lake restoration ; phosphorus ; sediments ; internal loading ; chemomanipulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After a reduction of the external phosphorus loading to a lake, an internal loading from the sediments may delay the improvement of the water quality. The accepted method to combat internal loading is careful dredging of the upper sediment layers (Cooke et al., 1986), but this method is costly and time consuming. Addition of phosphorus binding agents to the sediments might offer an alternative. In the Netherlands the use of aluminum compounds, the most common phosphorus binding agent, for water quality improvement purposes is not favoured. Therefore a sediment treatment with a solution of iron(III)chloride was tested. Iron was chosen because it is considered to be a natural binder of phosphate. 100 g m−2 of Fe3+ were added to the sediments of the shallow (1.75 m average depth) and eutrophic Lake Groot Vogelenzang (The Netherlands) in October and November 1989. The iron(III)chloride solution was diluted 100 times with lake water and mixed with the surface sediments with a water jet. Following the addition the concentrations of total phosphorus (Fig. 1), chlorophyll-a and suspended solids decreased. This improvement of the water quality lasted for three months. After this time the total phosphorus concentration increased again, but remained at a lower level than in spring and summer of 1989. The phosphorus release rate from the sediments as measured from intact sediment cores decreased from 4 to 1.2 mg P m−2 d−1 (n = 5), and the bioavailability of the sediment phosphorus, as measured with bioassays, decreased from 34 to 23% (n = 5) shortly after the treatment. One year after the treatment the release rate was increased to 3 mg P m−2 d−1 (n = 5). Before treatment, the lake was thought to have a residence time of over one year. However, the chloride added to the lake disappeared according to a dilution rate of 0.03 d−1 or a retention time of about 35 days. A high external loading due to rapid flushing with phosphorus-rich water from surrounding lakes possibly prevented a more durable improvement in water quality. Another possibility is that the iron addition has lost its phosphate binding capacity due to reduction or binding with other anions like carbonate or sulphide. Therefore the suitability of the method to reduce internal loading and especially the long term availability of added iron to bind phosphorus needs additional proof. The treatment of the 18 ha area of Lake Groot Vogelenzang took three weeks. The operational costs were about US$ 125000. This is fast and cheap compared to dredging. Application of the technique is limited to those cases where the sediments are not polluted with micro-pollutants and the water depth need not be increased.
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  • 79
    ISSN: 1573-5117
    Keywords: eutrophication ; lakes ; phosphorus ; chloride ; loading ; dynamic mass balance model ; sensitivity analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In 1984 a frequent monitoring programme was started in the hypertrophic S.W. Frisian lake district, with emphasis on total phosphorus (TP) and chloride (Cl−). The main objectives of the project were: to quantify the phosphorus flows, to gain insight in the process of eutrophication, and to simulate management scenarios. The seasonal variability in the lakes is due mainly to the man-made hydrology: reception of humic-rich polder water in wet periods (winter) and inlet of chloride-rich Usselmeer water in dry periods (summer). The yearly means of TP concentrations in the lakes (Tjeukemeer, Groote Brekken and Slotermeer) ranged from 0.23 to 0.29 mg l−1. However, much higher concentrations (0.9 mg l−1) were found in periods with high inflow of polder water. The simulations with a mass balance showed an acceptable similarity between measured and simulated concentrations of TP as well as of Cl−. Chloride was modelled to verify the accuracy of a hydrodynamic model. A sensitivity analysis of the apparent settling rate in the P model showed that sensitivity was lowest in simulations of Groote Brekken and highest in simulations of Slotermeer, the difference being attributable to the influence of the water residence time. The model was found to be appropriate for simulating management scenarios.
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  • 80
    ISSN: 1573-5117
    Keywords: model ; simulation ; eutrophication ; phosphorus ; P/C ratio ; lake ecosystem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus cycle in the ecosystem of the shallow, hypertrophic Loosdrecht lakes (The Netherlands) was simulated by means of the dynamic eutrophication model PCLOOS. The model comprises three algal groups, zooplankton, fish, detritus, zoobenthos, sediment detritus and some inorganic phosphorus fractions. All organic compartments are modelled in two elements, carbon and phosphorus. Within the model system, the phosphorus cycle is considered as completely closed. Carbon and phosphorus are described independently, so that the dynamics of the P/C ratios can be modelled. The model has been partly calibrated by a method based on Bayesian statistics combined with a Range Check procedure. Simulations were carried out for Lake Loosdrecht for the periods before and after the restoration measures in 1984, which reduced the external phosphorus loading to the lake from ca. 2 mgP m−2 d−1 to 1 mgP m−2 d−1. The model outcome was largely comparable withthe measured data. Total phosphorus has slowly decreased from an average 130 µgP l−1 to ca. 80 µgP l−1, but chlorophyll-a (ca. 150 µg 1−1, summer-averaged) and seston concentrations (8–15 mgC 1−1) hardly changed since the restoration measures. About two-thirds of the seston consisted of detritus, while the phytoplankton remained dominated by filamentous cyanobacteria. The P/C ratio of the seston decreased from ca. 1.0% to 0.7%, while the P/C ratios of zooplankton, zoobenthos and fish have remained constant and are much higher. The system showed a delayed response to the decreased phosphorus loading until a new equilibrium was reached in ca. five years. Major reasons for the observed resilience of the lake in responding to the load reduction are the high phosphorus assimilation efficiency of the cyanobacteria and the high internal recycling of phosphorus. A further reduction of nutrient loading, perhaps in combination with additional measures like biomanipulation, will be the most fruitful additional restoration measure.
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  • 81
    ISSN: 1573-5117
    Keywords: Microcystis ; microbial activity ; sediment ; phosphorus ; internal loading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variations in microbial biomass and activity in the sediments of hypereutrophic Lake Vallentunasjön were followed during a period of 5 years. The data were compared to the calculated release of phosphorus from the sediments during the same period. A strong co-variation was found between biomass of Microcystis, heterotrophic bacterial activity in the sediments and internal phosphorus loading. These parameters exhibited mainly a declining trend during the investigation period. A pronounced stability of the sediment chemistry, including the fractional composition of the sediment phosphorus, during the studied period indicates that microbial activity affected the phosphorus release from the sediments. Calculations of the percentage of sediment bacteria that was associated to the mucilage of Microcystis colonies imply, together with the specific bacterial production, that Microcystis in the sediment stimulates bacterial production. In the highly phosphorus-saturated sediments of Lake Vallentunasjön this would ultimately lead to an increased release of phosphorus from the sediment. Lake Vallentunasjön does not follow the common pattern of recovery after reduction of external phosphorus loading. The large biomasses and long survival of Microcystis in the sediment are probably important reasons for the delayed recovery of the lake.
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  • 82
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    Hydrobiologia 235-236 (1992), S. 585-596 
    ISSN: 1573-5117
    Keywords: estuary ; iron ; phosphorus ; organic carbon ; aggregation ; sedimentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The turnover of iron, phosphorus and organic carbon was followed in the Öre Estuary, northern Sweden, during the spring flood periods of 1989 and 1990. River-supplied material rapidly sediments out of the water column and is primary deposited within the estuary. The removal of iron and phosphorus is complete, with the calculated sedimentation exceeding the total amounts of particulate and dissolved iron and phosphorus supplied by the river. Aggregation of dissolved or colloidal iron-phosphate complexes due to increasing salinity and pH in combination with adsorption on rapidly sedimentating inorganic particles is suggested to explain this estuarine filter effect. Organic carbon is only affected by aggregation and sedimentation to a minor extent.
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  • 83
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    Hydrobiologia 243-244 (1992), S. 105-111 
    ISSN: 1573-5117
    Keywords: phosphorus ; transformations ; humic forest lake
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    Topics: Biology
    Notes: Abstract Research on epilimnetic phosphorus transformations in lakes had led to the establishment of a generalised picture which is promoted in reviews and textbooks. However, it would be wrong to believe that this established view can be applied to all lakes. Certainly the transformations of phosphorus in the summer epilimnia of small, coloured, humic forest lakes in southern Finland show features which deviate markedly from the generally accepted paradigm. (1) The plankton appears to be limited simultaneously by P and N rather than being strongly P limited. (2) Particulate P is typically a rather small fraction of the total P. (3) Molybdate reactive P may be a large part of the total P, although much of this MRP is not free orthophosphate, especially in highly humic lakes. (4) Turnover times for PO4-P are normally long (50–1000 minutes); turnover times appear to be longer in highly humic lakes. (5) Added 32 PO4 passes rapidly to macrozooplankton, apparently with rapid turnover of zooplankton phosphorus. (6) Sedimentation of phosphorus from the typically shallow epilimnion appears high, but may be partially compensated by biological retrieval of phosphorus from the phosphorus-rich hypolimnion.
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  • 84
    ISSN: 1573-5117
    Keywords: fertilization ; phosphorus ; nitrogen ; phytoplankton ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Hecklan, in central Sweden, was fertilized with phosphorus and nitrogen during thermal stratification (late May-early Oct) 1984–1987. The nutrient additions were relatively small and raised the total phosphorus concentrations from 6 to 10 µg l−1. The working hypothesis was that this moderate increase in the phosphorus concentration could increase the phytoplankton biomass without adverse changes in the planktonic community structure. The fertilization increased the phytoplankton biomass from 0.1 to a maximum of 2 mm3 l−1. Chrysophyceae and Cryptophyceae dominated throughout the experimental period. Thus, the phytoplankton composition remained typical for a Swedish forest lake and provided a potential for increased zooplankton growth. An increased growth of zooplankton was indicated by increased biomass of Cladocera and Copepoda in 1984 and 1985, and by increased fecundity of herbivorous zooplankton.
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  • 85
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    Hydrobiologia 243-244 (1992), S. 341-349 
    ISSN: 1573-5117
    Keywords: mass balance ; modelling ; phosphorus ; sedimentation ; CSTR ; PFR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mass balance models for elongated lakes have been developed. In these models particular attention is paid to the hydraulic description of the lake and to the description of net sedimentation. The hydraulic description is a linear combination of CSTR and PFR, with a coefficient regulating the degree of mixing. The PFR description was modified so that also additional input along the lake can be considered. Net sedimentation is described either as a first order or a second order reaction. Both voluminal and areal sedimentation is possible in the models. The models were tested against phosphorus balance data for two Finnish lakes. Lake Haukivesi and Lake Päijänne. In both lakes the PFR model with additional input together with second order net sedimentation gave the best fit to observations. The values of the sedimentation coefficients are not universal but vary from lake to lake. They are also dependent on the hydraulic description used in the model. There is a critical point for the monitoring of the lake at which measurements give the same sedimentation coefficient regardless of the hydraulic description.
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  • 86
    ISSN: 1573-515X
    Keywords: nitrogen fixation ; phosphorus ; internal loading ; water hyacinth ; floodplain ; Paraná ; flood-pulse hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Some aspects of nutrient status and dynamics prevailing during low and high water conditions in the fringing floodplain ponds of the Paraná River dominated by the floating macrophyte Eichhornia crassipes are described. During summertime low water conditions, low DIN:DRP ratios (0.16–1.0) and low DIN (0.5–4.8 μmol.liter−1) in the root-zone of the floating meadows suggest that macrophyte growth is limited by nitrogen. DRP concentrations appear to be controlled more by abiotic sorption-dissolution than by biological reactions. Preflood nutrient fluxes from the sediments, as estimated from porewater profiles, show that a minimum of 1.19 and 0.38 mmol.m−2.d−1 of DIN and DRP were regenerated from the sediments, respectively. Heterotrophic N2 fixation is primarily associated with decaying litter (0.4 to 3.2 μmolN2.g−1.d−1). Nutrient recycling from sediments and meadow-litter, and heterotrophic N2 fixation (1.4 mmolN.m−2.d−1) appear sufficient to sustain high floating macrophyte productivity for long periods of time, without invoking large inputs from the river. The high water and early isolation periods are characterized by a very dynamic behavior of DIN, reflecting marked imbalances between N supply and demand by the biota. After hydrologic isolation of the ponds, DIN rapidly decreases to undetectable levels and stays low for the following 3 weeks, presumably as a result of high demand by phytoplankton and sediment bacteria. DIN increases again to high values 3–8 weeks after the flood, following the re-establishment of NH4 + fluxes from the sediments. Compared to DIN, DRP concentrations remain relatively high and change little during and after the flood. Because of their small amplitude and short duration, floods do not appear to stimulate floating macrophyte production in the Paraná.
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  • 87
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    Biogeochemistry 18 (1992), S. 19-35 
    ISSN: 1573-515X
    Keywords: Dinitrogen fixation ; nitrogen ; phosphorus ; competition ; legumes
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    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract An analysis of data compiled from the literature confirms a strong inverse relationship between annual rates of nitrogen fixation and the soil nitrogen content in agricultural and pastoral ecosystems. However, this inverse relationship is strongly modified by the rate of application of phosphorus fertilizer, which strongly influences the activities of both symbiotic and non-symbiotic nitrogen fixing organisms. In the case of symbiotic legumes, the response of N-fixation to N and P is in part a result of changes in legume dominance within the plant community. These results, as well as supporting data presented from a review of experiments on nitrogen fixation in a variety of other terrestrial and aquatic ecosystems, provide important support for the hypothesis that phosphorus availability is a key regulator of nitrogen biogeochemistry.
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  • 88
    ISSN: 1573-515X
    Keywords: nitrogen ; phosphorus ; soil fertility ; tropical forest
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    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract We measured concentrations of soil nutrients (0–15 and 30–35 cm depths) before and after the dry season in control and dry-season irrigated plots of mature tropical moist forest on Barro Colorado Island (BCI) in central Panama to determine how soil moisture affects availability of plant nutrients. Dry-season irrigation (January through April in 1986, 1987, and 1988) enhanced gravimetric soil water contents to wet-season levels (ca. 400 g kg−1 but did not cause leaching beyond 0.8 m depth in the soil. Irrigation increased concentrations of exchangeable base cations (Ca2+, Mg2+, K+, Na+), but it had little effect on concentrations of inorganic N (NH4 +C, NO3 − and S (SO4 2−). These BCI soils had particularly low concentrations of extractable P especially at the end of the dry season in April, and concentrations increased in response to irrigation and the onset of the rainy season. We also measured the response of soil processes (nitrification and S mineralization) to irrigation and found that they responded positively to increased soil moisture in laboratory incubations, but irrigation had little effect on rates in the field. Other processes (plant uptake, soil organic matter dynamics) must compensate in the field and keep soil nutrient concentrations at relatively low levels.
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  • 89
    ISSN: 1573-1561
    Keywords: Trichoplusia ni ; Lepidoptera ; Noctuidae ; sex pheromone ; inhibitor ; (Z)-7-dodecenol ; wind tunnel ; orientation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (Z)-7-Dodecenol failed to interrupt pheromone-mediated anemotactic responses by male cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) in a wind tunnel when released 5 cm crosswind on both sides of the pheromone source or 10 cm upwind of the source to create an overlapping plume downwind. Significant inhibitory effects of (Z)-7-dodecenol were observed when released with the six-component pheromone blend from the same septum or abutting septa. These results indicate that (Z)-7-dodecenol needs to be received simultaneously with the pheromone blend to inhibit the anemotactic responses of males to the sex pheromone. We suggest that this feature and the filamentous nature of pheromone plumes render pheromone signals relatively protected from background chemical noise that may originate from pheromone plumes of other insect species. Unless filaments from a pheromone signal and an inhibitor arrive simultaneously, the integrity of the signal is maintained.
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  • 90
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    Journal of chemical ecology 18 (1992), S. 353-358 
    ISSN: 1573-1561
    Keywords: Pheromone ; oviposition-deterring pheromone ; oviposition ; Lobesia botrana ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Females of the European grapevine moth (Lobesia botrana Den. et Schiff.) usually deposit isolated eggs on flowers and berries of the grapevine (Vitis vinifera L.). We have investigated whether an epideictic pheromone could be present on the egg surface to explain this spacing behavior. About 21,000 eggs ofL. botrana were washed in cold methanol, and the biological activity was tested in a two-choice bioassay offering treated and nontreated areas. Different dilutions of the extract were tested in methanol, which was inactive alone. At the dose of four egg equivalents per microliter of extract, the number of eggs laid by theL. botrana females was reduced by as much as 57% on the treated areas compared to nontreated areas. A longer-term suppression of oviposition (at least 24 hr) following an exposure to the extract occurred for two doses (0.6 and 4.0 eggs/μl) of egg extract. Our results strongly suggest the occurrence of an oviposition-deterring pheromone (ODP) on the eggs ofL. botrana. The ecological value of these results is discussed.
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  • 91
    ISSN: 1573-1561
    Keywords: Allelochemistry ; Bermuda grass ; Cynodon dactylon ; phagostimulant ; Spodoptera frugiperda ; Lepidoptera ; Noctuidae ; fall armyworm ; 6,10, 14-trimethylpentadecan-2-one
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A phagostimulant, 6,10,14-trimethylpentadecan-1-one (phytone), was isolated and identified from Bermuda grass,Cynodon dactylon (L.). The phagostimulant activity of this isoprenoid ketone was established from bioassays of fall armyworm larvae,Spodoptera frugiperda (J.E. Smith). Larvae displayed increased body mass accumulation as well as preference to diet supplemented with this molecule. Neonate larvae fed diet supplemented with chromatographic isolates of phytone-containing fractions from six Bermuda grass cultivars showed a 10–40% increase in body mass accumulation as compared with controls. This variation in larval body mass accumulation seems attributable to a differential concentration of phytone in the cultivars, which ranged from 0.5 to 43 ppm. Additionally, first-instar larvae responded preferentially to diet pellets topically treated with phytone in concentrations as low as 0.1 ppm.
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  • 92
    ISSN: 1573-1561
    Keywords: Lobesia botrana ; Vitis vinifera ; Tanacetum vulgare ; tansy ; grapevine ; Lepidoptera ; Tortricidae ; Compositae ; plant-insect relationships ; olfaction ; allelochemicals ; terpenoids ; coupling GC-EAG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The European grapevine moth (EGVM),Lobesia botrana, is a major pest of grapes in Europe. Females are attracted to a nonhost plant: tansy (Tanacetum vulgare L.), which is a common weed in Slovakian vineyards. A steam distillate extract of tansy flowers was analyzed by means of a GC-EAG technique to screen constituents detected by the olfactory receptors of EGVM females. From more than 200 GC peaks, nine peaks corresponding to monoterpenoids released an EAG response in more than 70% of the females (N=15):p-cymene,d-limonene,α-thujene,α-thujone,β-thujone, thujyl alcohol, terpinene-4-ol, (Z)-verbenol, and piperitone. The steam distillate of tansy as well as a synthetic blend of identified compounds released consistent attraction in a field cage. The use of nonhost plants and host plant odors in integrated pest management is discussed.
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  • 93
    ISSN: 1573-1561
    Keywords: (Z)-7-Dodecenyl acetate ; (Z)-9-tetradecenyl acetate ; pheromone blend kwTrichoplusia ni ; flight behavior ; flight tunnel ; pheromone analog ; perfluoroalkyl substitution ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Substitution of nine hydrogens by nine fluorines in the butyl terminus of (Z)-7-dodecenyl acetate, the major component of the pheromone blend of the cabbage looper,Trichoplusia ni (Lepidoptera: Noctuidae), produces a highly volatile analog that is significantly less active as a replacement for the natural pheromone component, either alone or substituted in the sixcomponent pheromone blend of this species. When 9,9,10,10,11,11,12,12, 12-nonafluoro-(Z)-7-dodecenyl acetate (nf-Z7-12: OAc) was tested in a wind tunnel as a single component or as part of the six-component blend, males exhibited preflight activation, but they did not orient in the pheromone plume and fly upwind over a five-decade range of doses at levels comparable with those of the natural component and blend. Addition of large amounts of nf-Z7-12:OAc to the optimal dose of the natural blend also did not effect flight arrestment as when increased amounts of Z7-12:OAc were added. The nonafluoro (nf) analog of (Z)-9-tetradecenyl acetate, a minor component in theT. ni blend, did not affect male behavior when substituted in the sixcomponent blend, and substitution of both nf analogs in the natural blend produced the same results as observed for blends containing nf-Z7-12:OAc. The lack of an effect with substitution of nf-Z9-14:OAc is discussed in relation to the reported redundancy in the action of minor components inT. ni.
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  • 94
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    Journal of chemical ecology 18 (1992), S. 1437-1453 
    ISSN: 1573-1561
    Keywords: Tannins ; phenolics ; surface tension ; surfactants ; lysolecithin ; lysophosphatidylcholine ; lipids ; detergents ; protein ; Lymantria dispar L. ; gypsy moth ; Lepidoptera ; Lymontriidae ; red oak ; Quercus rubra L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Surface-active lysophospholipids are thought to interfere with tannin-protein interactions and may comprise an adaptation in Lepidoptera to tannin-rich diets. We found several lysophospholipids and phospholipids at about eight times the critical micelle concentration (CMC) in the midguts of gypsy moth larvae, which exhibited appropriately reduced surface tensions. We confirmed the interfering activity of lysophosphatidylcholine (lysolecithin) in a model astringency assay using tannic acid and hemoglobin (hemanalysis), but discovered that tannic acid and red oak tannin extracts precipitate the lipid from simulated midgut solutions quantitatively, even at pH 10. Leaf tannin extracts from trees on which gypsy moths grew and reproduced poorly precipitated lysolecithin more effectively than did extracts from trees on which gypsy moths performed well. Adding tannic acid to midgut fluid elevated surface tension, and about 25% of larvae feeding on oak leaves exhibited elevated midgut surface tension, suggesting a loss of surfactants. Larvae appear able to replace lost surfactants to a limited degree. An important effect of leaf tannins, and perhaps other phenolics, may be to reduce concentrations of surface-active phospholipids in the midgut and produce lipid or other dietary deficiencies in insects.
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  • 95
    ISSN: 1573-1561
    Keywords: Sex pheromone ; codling moth ; Cydia pomonella ; Lepidoptera ; Tortricidae ; Olethreutinae ; controlled release ; mating disruption ; dodecan-1-ol ; tetradecan-1-ol ; (E,E)-8,10-dodecadien-1-ol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Performance characteristics of polyethylene tube dispensers containing a mixture of (E,E)-8,10-dodecadien-1-ol (1), dodecan-1-ol (2), and tetradecan-1-ol (3) were evaluated for suitability as a mating disruptant for codling moth control. The rate of loss of pheromone component from a dispenser at any time was found to be described by the equation: −dP/dt=(k 1 k 2 +k d)P whereP is the amount of pheromone component in the dispenser well;t is time;k 1 is the ratio of the amount dissolved in the dispenser wall to the amount in the dispenser well;k 1 is the ratio of the evaporation rate to the amount dissolved in the dispenser wall;k d is the rate constant for chemical decomposition. The evaporation rate,E, of a pheromone component at any time was given by:E=k 1 k 2 P For all three components during the first three weeks,k 1 decreased from ca. 0.25 to ca. 0.10 and was approximately constant thereafter. The decrease ofk 1 with time may have been caused by weather-induced cross-linking of the polyethylene. Over timek 2 was constant and was 1.27 ± 0.26 × 10−3/hr for1, 1.96 ± 0.33 × 10su−3/hr for 2, and 0.31± 0.05 × 10−3/hr for 3. Thek 2 was zero for2 and3 and 6.96 × 10−4 for1. After 150 days in an orchard in 1991, 95% of1 was lost from the dispensers (61% of the loss was by chemical decomposition and 39% by evaporation). The heat summation units in a Yakima valley orchard during 1991 were 4.7% above the average for the 1980–1991 period, while during 1990 they were the highest for this period (26% above average). After the first three weeks of dispenser aging, the regression line half-lives for1 for 1990 and 1991 were 31.0 and 35.1 days, respectively. The difference in temperature between 1990 and 1991 did not affect the half-life of1 very much because so much of the loss was from photochemically induced decomposition. Based on an estimate of the required minimum evaporation rate for mating disruption of 2 mg/ha-hr and a half-life of 35 days for1, 2345 dispensers/ha would be required for one application per season; 944 dispensers/ha for two applications per season; and 734 dispensers/ha for three applications per season. If a different emission rate of1 is required for reliable mating disruption, then the number of dispensers required would be changed proportionately.
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  • 96
    ISSN: 1573-1561
    Keywords: Insect sex pheromone ; mulberry clearwing moth ; Lepidoptera ; Sesiidae ; Paradoxecia pieli L. (E,Z)-3,13-octadecadien-yl acetate ; (E,Z)-3,13-octadecadien-1-ol ; single cell recording ; EAG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract (E,Z)-3,13-OctadecadienyI acetate (1a) and (E,Z)-3,13-octadecadien-1-ol(2a) were identified from the sex pheromone gland of the virgin female mulberry clearwing mothParadoxecia pieli L., by GC analysis, EAG, SCR survey, and field bioassay. One female equivalent contained 250 ng of1a and 30 ng of2a. In the field tests, 100μg of synthetic1a was attractive to male moths of the species.
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  • 97
    ISSN: 1573-1561
    Keywords: Insect olfaction ; electrophysiology ; pyrrolizidine alkaloids ; Utetheisa ornatrix ; Lepidoptera ; Arctiidae ; hydroxydanaidal ; male-produced ; pheromone ; olfactory receptor neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The olfactory receptor neurons in basiconic sensilla on the antennae ofUtetheisa ornatrix, which, in females, had earlier been shown to be responsive to stimulation with hydroxydanaidal (HD), are here shown to be responsive to volatile substances in samples of pyrrolizidine alkaloids (PAs). These latter substances are secondary plant metabolites present in the host plant of the larvae. Their sequestration during larval life serves to protect all life stages from predation. In males, the PAs also provide precursors for the production of the male pheromone, HD. In females, basiconic receptor neurons begin to respond to stimulus cartridges containing 1 ng of (R)-(−)-hydroxydanaidal, 100 ng of its isomer, (S)-(+)-hydroxydanaidal, and to volatiles emanating from 10μg of the alkaloids monocrotaline and heliotrine. Receptor neurons in males are generally responsive to the same array of substances but with reduced sensitivity. The dietary background of the adult moths with respect to prior ingestion of PAs does not influence the response capabilities of basiconic receptor neurons to HD or to the volatile components of PAs. Earlier studies in another arctiid (Rhodogastria), had indicated that trace amounts of HD are present in PAs, presumably as their hydrolysis product. Thus we assume that, under natural conditions, HD may be an active component of the volatiles from PAs and may serve as both a male pheromone and a kairomone. Sensitivity to HD could thereby provide information about the location and PA content of potential mates and food plants. Mechanisms that may have resulted in the evolution of a signaling system with these properties are discussed.
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  • 98
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    Journal of chemical ecology 18 (1992), S. 441-453 
    ISSN: 1573-1561
    Keywords: Male-produced pheromone ; cabbage looper ; Trichoplusia ni ; Lepidoptera ; Noctuidae ; female attractant ; linalool ; p-cresol ; m-cresol ; enantiomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A multicomponent pheromone produced by male cabbage looper moths that is attractive to female moths in a flight tunnel bioassay was isolated and identified. Based on analyses of hairpencil extracts of male cabbage loopers and volatiles emitted by males, the pheromone has been identified as a blend consisting of (S)-(+)-linalool,p-cresol, andm-cresol. The chirality of the major component, (S)-(+)-linalool, is important for behavioral response of females. These pheromonal compounds were also identified as volatiles released by males when males were exposed to the principal pheromone component of female cabbage loopers, (Z)-7-dodecen-1-ol acetate. The amount of male pheromone released was increased significantly when males were exposed to a combination of (Z)-7-dodecen-1-ol acetate and the odor from cabbage. Neither linalool nor the cresols were detected in volatiles from cabbage or from males exposed to cabbage odor.
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  • 99
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    Journal of chemical ecology 18 (1992), S. 481-488 
    ISSN: 1573-1561
    Keywords: Amino acids ; Solanum tuberosum ; Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae ; Empoasca fabae ; Homoptera ; Cicadellidae ; feeding damage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Feeding by Colorado potato beetles and artificial defoliation had a minor effect on the profile of amino acids in potato foliage, whereas feeding by potato leafhoppers caused an increase in about one half of the amino acids measured.
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  • 100
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    Journal of chemical ecology 18 (1992), S. 489-498 
    ISSN: 1573-1561
    Keywords: Coleoptera ; Carabidae ; beetles ; Helluomorphoides clairvillei ; defensive secretion ; formic acid ; acetates ; formates ; hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive spray of a single female of the rare carabid beetle,Helluomorphoides clairvillei (subfamily Carabinae, supertribe Lebiitae, tribe Helluonini). was found to contain a mixture of compounds, including carboxylic acids (formic, acetic), aliphatic esters (principally nonyl acetate), and hydrocarbons (principally decane). In a single series of discharges, the beetle ejected a total of about 1% of its body weight as formic acid (1.1 mg). Our findings demonstrate that characterization of secretory components from even minimal samples of secretion should be possible in many cases.
    Type of Medium: Electronic Resource
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