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  • Lepidoptera  (1,142)
  • Photosystem II  (1,079)
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  • 1
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; reproduction ; tebufenozide ; methoxyfenozide ; ecdysone agonist ; Argyrotaenia velutinana ; Choristoneura rosaceana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects on the fecundity and fertility of redbanded leafroller, Argyrotaenia velutinana (Walker), and obliquebanded leafroller,Choristoneura rosaceana (Harris), exposed as adults to surfaces treated with the ecdysone agonists tebufenozide (RH-5992) and methoxyfenozide (RH-2485) were examined. The first part of the study consisted of recently emerged moths being exposed to treated surfaces continuously throughout their lives (including mating and oviposition). Continuous exposure to tebufenozide- or methoxyfenozide-treated surfaces significantly reduced the mean number of eggs laid and the percent of eggs that hatched in both species. The second part of the study involved exposure of recently emerged virgin moths (by sex) to treated surfaces for 24 h, after which, the exposed moths were paired with a nontreated partner to mate and oviposit on nontreated surfaces. In this experiment, for A. velutinana, significant reductions in fecundity occurred only when the female was exposed to methoxyfenozide-treated surfaces. Significant reductions in A. velutinana egg fertility occurred with both male and female exposure in the methoxyfenozide treatments and only female exposure in the tebufenozide treatments. For C. rosaceana, significant reductions in fecundity occurred with both male and female exposure in the tebufenozide and methoxyfenozide treatments. Significant reductions in C. rosaceana egg fertility occurred with both male and female exposure in the tebufenozide treatments and only with female exposure in the methoxyfenozide treatments.
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  • 2
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    Entomologia experimentalis et applicata 95 (2000), S. 217-227 
    ISSN: 1570-7458
    Keywords: antifeedant ; drimane ; mechanism of action ; sensory response ; toxicity ; habituation ; behavioural observation ; structure-activity relationship ; Pieris brassicae ; Lepidoptera ; Pieridae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We tested 11 analogous synthetic drimane antifeedant compounds for their feeding inhibiting effects on larvae of the large white butterfly Pieris brassicae L. (Lepidoptera: Pieridae) in no-choice tests on the host plant Brassica oleracea L. Furthermore, we observed larval feeding behaviour in no-choice tests to analyze temporal effects of five drimanes. The results show that the five analogous antifeedants differentially influence feeding behaviour and locomotion activity. Warburganal and polygodial are most likely sensory mediated antifeedants. Habituation to these compounds occurs soon after the onset of the tests (i.e., within 0.5–1.5 h). Compound 5 and confertifolin are probably not direct, sensory mediated antifeedants. After 0.5–1.5 h of exposure, these compounds inhibit not only feeding, but also locomotion behaviour, indicating postingestive, toxic effects. Isodrimenin inhibits feeding from the onset of the test and is probably a sensory mediated antifeedant. No habituation occurs to this compound, indicating that isodrimenin is either a very strong antifeedant or that it additionally has postingestive, toxic effects. Topical application of the drimanes on the larval cuticle revealed feeding inhibiting effects, but these could not be related to the occurrence of postingestive feeding inhibiting effects, indicating that this method is inappropriate to show possible postingestive effects of drimanes in P. brassicae. In conclusion, the behavioural observations performed in this research indicate that analogous drimanes inhibit feeding by P. brassicae larvae through multiple mechanisms of action. The results show that, when developing a structure activity relationship (SAR) for a series of antifeedants, it is important to distinguish the mode of action which underlies inhibition of feeding.
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  • 3
    ISSN: 1570-7458
    Keywords: Cnaphalocrocis medinalis ; rice leaffolder ; Lepidoptera ; Pyralidae ; sex pheromone ; geographical variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sex pheromone components of the Japanese rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) were identified from ovipositor extracts of virgin females as (Z)-11-octadecenal, (Z)-13-octadecenal, (Z)-11-octadecen-1-ol and (Z)-13-octadecen-1-ol at a ratio of 11:100:24:36 by GC-EAD, GC, GC-MS. The total amount was estimated to be ca.0.9 ng/female. Field bioassays in Kagoshima, Japan, showed that the two aldehydes are essential for male attraction and the alcohols may have a synergistic effect on the aldehydes. A rubber septum containing 0.9 mg of the four components at the natural ratio was shown to be an effective lure for monitoring this pest in Japan. The above four components are quite different from the sex pheromone components reported previously for the same species of either Philippine or Indian origin; components were shown to be (Z)-11-hexadecenyl acetate and (Z)-13-octadecenyl acetate at a ratio of 98:2 in the Philippine blend and 1:10 in the Indian blend. Furthermore, in the field tests in Japan, neither the Philippine blend nor the Indian blend showed any attractive activity, while the Japanese blend attracted significant numbers of male moths. These results suggest that there are remarkable geographical variations in the sex pheromone composition of this species or there are several distinct species using different sex pheromone blends.
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  • 4
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    Entomologia experimentalis et applicata 97 (2000), S. 137-147 
    ISSN: 1570-7458
    Keywords: Etiella zinckenella ; Etiella hobsoni ; Lepidoptera ; Pyralidae ; soybean ; development ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments conducted in West Java, Indonesia investigated the developmental biology and reproductive behavior of two sympatric soybean pod borers, Etiella zinckenella Treitschke and E. hobsoni Butler (Lepidoptera: Pyralidae). It was determined that: (1) significant interspecific differences occurred between the egg, larval, pupal and total egg-to-adult developmental periods of laboratory raised E. zinckenella and E. hobsoni; (2) the pre-pupal and total egg-to-adult development periods of female E. zinckenella were significantly shorter than for males; (3) the longevity of virgin female E. zinckenella was significantly longer than that of virgin males, or virgin male and female E. hobsoni; (4) interspecific differences occurred in the female: male sex-ratios of laboratory raised adults; (5) peak mating for both species occurred on the second night after eclosion; (6) interspecific differences occurred in the temporal distribution of calling and mating behaviors; (7) repeated mating was observed for both species at a very low frequency; (8) interspecific mating did not occur; (9) female E. zinckenella were significantly more fecund than E. hobsoni; (10) the duration in copulo of E. zinckenella was significantly longer than that of E. hobsoni; and (11) wingtraps baited with virgin females caught only conspecific males, and reduced numbers of males were captured in traps simultaneously baited with virgin females of both species. This study demonstrates distinct biological differences and reproductive isolation between the two Etiella spp.
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  • 5
    ISSN: 1570-7458
    Keywords: calling behaviour ; periodicity ; sex pheromone ; attraction inhibitor ; attraction synergist ; field tests ; Lepidoptera ; Gracillariidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Females of the leaf miner moth Phyllonorycter acerifoliella (Z.) [=Ph. sylvella (Hw.)] and Ph. heegerella (Z.) (Lepidoptera: Gracillariidae: Lithocolletinae) release their sex pheromone at the beginning of photophase. The periodicity of the `calling' behaviour of Ph. acerifoliella females was established. Three compounds from calling virgin Ph. heegerella females were collected by the Solid Phase Micro Extraction (SPME) technique and identified as (Z)-8-tetradecenyl acetate (Z8-14:OAc), tetradecyl acetate (14:OAc) and (Z)-8-tetradecenol (Z8-14:OH) in the ratio (88±3):(2±0.6):(10±5) by capillary gas chromatography and mass spectrometry. Field trapping experiments demonstrated that the first two compounds are important for the attraction of conspecific males. Z8-14:OAc was found to be attractive when tested separately, while 14:OAc acted as synergist. The attractivity of the three component blend was reduced by 10% admixture of either (E)-10-dodecenyl acetate (E10-12:OAc) or (Z)-10-tetradecenyl acetate (Z10-14:OAc). Field tests of Z10-, Z8- and E10-14:OAc, identified from Ph. acerifoliella females, demonstrated that the first two compounds were essential for the attraction of conspecific males; so both are sex pheromone components. The attractivity of the three component blend of Z10- Z8- and E10-14:OAc was reduced by 10% admixture of (E)-10-dodecenol (E10-12:OH). The following four semiochemical compounds, Z8-14:OAc, Z8-14:OH, E10-14:OAc and 14:OAc, identified from phyllonoryctid females, as well as two sex attraction antagonists for Ph. acerifoliella and Ph. heegerella males, E10-12:OAc and Z10-14:OAc, are new for the family Gracillariidae. The results of field trapping experiments revealed mechanisms ensuring the specificity of the chemocommunication systems in Ph. acerifoliella, Ph. heegerella and Ph. ulmifoliella (Hb.) moths.
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  • 6
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    Entomologia experimentalis et applicata 97 (2000), S. 339-346 
    ISSN: 1570-7458
    Keywords: crygenes ; PCR ; Lepidoptera ; Spodoptera ; insecticidal activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thirty-five strains of the entomopathogenic bacterium Bacillus thuringiensisactive on Spodoptera exigua, were characterized by means of serological identification and determination of crygene contents by PCR. The insecticidal activity of these 35 strains was further confirmed against S. exiguaand tested against two other species of the same genus: S. littoralisand S. frugiperda. The results indicate that serovars aizawai, thuringiensis, and kurstakiwere the most frequent within S. exigua-active strains and that serovar aizawaihad the highest number of strains exhibiting toxicity against the three species bioassayed. The presence in crygenes as determined by PCR suggests a non random distribution of some crygenes among serovars. Genes cry1C, cry1D, and cry1E, which are known to code for proteins toxic against Spodopteraspecies, were very common within S. exigua-active strains, specially in those belonging to serovar aizawai. However, some strains harbouring one or more of these genes were not toxic to S. littoralisor S. frugiperda; and some strains lacking all of the Spodoptera-active genes were found to be toxic to all three species. This suggests differences in the expression levels among strains bearing toxic genes and the involvement of other genes toxic to Spodopteraspecies. Since strains sharing the same crygenes exhibited different host ranges, the results indicate the need to perform toxicity bioassays in addition to other tests (serological identification and PCR) in order to determine the insecticidal activity of B. thuringiensisstrains.
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  • 7
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    Journal of insect behavior 13 (2000), S. 881-900 
    ISSN: 1572-8889
    Keywords: three-dimensional ; flight track recording ; orientation ; pheromones ; plant volatiles ; image analysis ; real time ; Lobesia botrana ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A computer-controlled video system for real-time recording of insect flight in three dimensions is described. The flight paths of moths were recorded in a flight tunnel using two CCD cameras placed adjacent to each other at angles of 45 and 135° to the flight tunnel axis and separated by a distance of 120 cm. They were connected to two 28-level gray-scale frame grabbers via two external synchronizers. The two-dimensional coordinates of the flying insect were obtained from the two cameras at 40-ms intervals and transferred to host computer for processing and monitor for real-time display. Due to speed limitation in the image acquisition hardware, construction of the three-dimensional file was carried off-line. The flying insect was rendered as a dark spot in a bright background using a homogeneous light source. As the insect enters into the field of view of the two cameras, the light distribution changes, and the frame grabber detects only those variation in the light distribution which results from a flying insect. The target insect can be as small as 3 pixels and can be tracked in a stereoscopic field of view 60 cm long and 50 cm high. A method was developed that allowed for scalar scoring of various pheromone sources to assess their attractiveness using vector flight parameters. This method was applied successfully for optimization of pheromone blend of the grapevine moth, Lobesia botrana.
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  • 8
    ISSN: 1437-5613
    Keywords: Key words Herbivory ; Plant–herbivore interaction ; Lepidoptera ; Cruciferous plants ; Vegetation texture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Correlation between plant size and reproductive output may be modified by herbivory in accordance with host plant density and the presence of nonhost plants. To elucidate the effects of nonhost plant density and host plant density on the intensity of herbivory and reproductive output of the host plant in relation to plant size under natural conditions, we investigated the abundance of three lepidopteran insects, Plutella maculipennis, Anthocharis scolymus, and Pieris rapae the intensity of herbivory, and fruit set of their host plant, Turritis glabra (Cruciferae). To elucidate the effects of nonhost and host plant density, we selected four categories of plots under natural conditions: low density of nonhost and high density of host plants; low density of both nonhost and host plants; high density of both nonhost and host plants; and high density of nonhost and low density of host plants. The plant size indicated by stem diameter was a good predictor of the abundance of all herbivorous species. The effects of density of nonhost and host plants on the abundance of insects varied among species and stages of insects. As the abundance of insects affected the intensity of herbivory, herbivory was more apparent on larger host plants in plots with low density of both nonhost and host plants. Consequently, the correlation between plant size and the number of fruits disappeared in low plots with density of both nonhost and host plants. In this T. glabra– herbivorous insect system, the density of nonhost plants and host plants plays an important role in modifying the relationship between plants and herbivores under natural conditions.
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  • 9
    ISSN: 1437-5613
    Keywords: Key words Community patterns ; Lepidoptera ; Route order ; Species richness ; Species distribution ; Environmental disturbance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Kitahara and Fujii, in 1994, analyzed the butterfly communities along a gradient of human disturbance by applying the generalist/specialist concept. Butterfly species were classified into generalist or specialist species based on their voltinism (seasonal time dimension) and potential larval resource breadth (food dimension). The community structure and species composition showed the systematic changes along the gradient. To verify the generality of those trends, we monitored five grassland butterfly communities with varying degrees of human disturbance twice a month during 1985 by the line transect method at the foot of Mt. Fuji, central Japan, and analyzed their structure in a manner similar to that employed by Kitahara and Fujii. Most results were consistent with the patterns recognized by Kitahara and Fujii. The route (community) order based on increasing human disturbance was strongly and negatively correlated with butterfly species richness but with neither butterfly species diversity (H′) nor evenness (J′). Also, the degree of human disturbance was significantly and negatively correlated with the number of specialist species, but not with that of generalists, in a community. Butterfly species richness was more strongly correlated with the number of specialist species than with that of generalists. Our analyses also showed that the generalist species were distributed more widely over the communities than were the specialists. However, in contrast to the trend revealed by Kitahara and Fujii, there was no significant difference in the population densities and in the spatial population variability between the two species groups. As a whole, our analyses confirmed the consistency of most community patterns detected by Kitahara and Fujii. The causes of the inconsistencies in some patterns were thought to be mainly the present habitat conditions with a relatively short growing season at high altitudes.
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  • 10
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    Journal of insect conservation 4 (2000), S. 73-77 
    ISSN: 1572-9753
    Keywords: mapping ; database ; bias recording ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract We use data from the Mersey Valley zone (3×2 km area; N = 600 I ha squares) of the Greater Manchester butterfly atlas to investigate whether recorder visits are biased by access (viz. distance from recorder's home base) and by the locations of potential hot spots. In a multiple regression analysis, visits were found to correlate significantly both with distance from home base of the recorder and with the mean and maximum number of species found in squares. Sites close to the home base of the recorder were visited more frequently than those further afield and squares with more species were visited more frequently than those squares with fewer species. Visits were also made significantly more frequently to squares with greater numbers of butterfly resources (e.g. hostplants, nectar). Furthermore, recording is biased to and away from distinct land uses, which vary significantly in species richness. Reasons are given why these biases are to be expected at all scales. The message is that future distribution mapping should be based on rigorous sampling approaches.
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  • 11
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    Oecologia 122 (2000), S. 1-10 
    ISSN: 1432-1939
    Keywords: Key words Distribution ; Gregariousness ; Larval strategy ; Lepidoptera ; Thermoregulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Group-living in animal populations has many possible ecological and evolutionary explanations, including predator evasion and feeding facilitation. In insects, the thermal balance of solitary and gregarious larvae is likely to differ and may thus have important ecological consequences. The abilities of the larvae of four species of nettle-feeding nymphalid butterflies to thermoregulate were quantified in the field. Larval surface body temperatures of the gregarious Aglais urticae (small tortoiseshell) and Inachis io (peacock) and the solitary Polygonia c-album (comma) and Vanessa atalanta (red admiral) were measured for each instar, in both sunny and overcast conditions, over a seasonal range of temperatures. The results suggested two distinct larval thermal strategies. In the presence of direct sunlight, the exposed gregarious larvae of A. urticae and I. io regulated body temperatures at 32.5 and 31.5°C, respectively, while the temperatures of concealed larvae of P. c-album and V. atalanta were largely dependent on ambient temperatures. In the sun, the range of body temperatures recorded for A. urticae and I. io larvae was fairly narrow relative to ambient temperatures. This suggests a high degree of thermal control in these species. Modal body temperatures coincided with the temperature at which development rate is maximal. Regardless of whether changes in thermoregulation are a cause or consequence of the evolution of gregariousness, the combination of behavioural thermoregulation and gregariousness in larval insects has important implications for voltinism patterns and range extension (via increased development rates). Distributional responses of gregarious and solitary larvae to climatic warming may differ as a result of changes in cloud cover as well as changes in temperature.
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  • 12
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    Oecologia 122 (2000), S. 36-43 
    ISSN: 1432-1939
    Keywords: Key words Life history theory ; Longevity ; Ageing ; Mortality rate ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Life history theory predicts that organisms should only invest resources into intrinsic components of life span to the degree that it pays off in terms of reproductive success. Here, we investigate if the temporal distribution of mating opportunities may have influenced the evolution of intrinsic mortality rates in the butterfly Pararge aegeria (Satyrinae). In this species, females mate only once and the frequency of male mating opportunities depends on the temporal emergence pattern of virgin females. As expected, in a population from Madeira where females emerge continuously throughout the year, there was no sex difference in adult life span, while in a Swedish population with synchronised female emergence, males had significantly shorter life spans compared to females. A logistic mortality model provided the best fit to the observed change in age-specific mortality and all categories reached an asymptotic mortality rate of a similar magnitude. However, the Swedish males reached this mortality plateau more rapidly than the other categories. External mortality, due to water and food limitation, affected the pattern of sex-specific mortality but males from Sweden still had higher rates of mortality compared to all other categories. We argue that selection on male longevity is likely to be weaker in Sweden because under synchronised emergence, all females emerge and mate within a short period of time, after which male reproductive value will quickly approach zero. On Madeira, however, male reproductive value decrease more slowly with age since the probability of finding a receptive female is constant over the year.
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  • 13
    ISSN: 1432-1017
    Keywords: Key words Lipid-protein interactions ; Photosystem I ; Photosystem II ; Thylakoid membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract  We address the segregation of photosystems I (PSI) and II (PSII) in thylakoid membranes by means of a molecular dynamics method. We assume a two-dimensional (in-plane) problem with PSI and PSII being represented by particles with different values of negative charge. The pair interactions between particles include a screened Coulomb repulsive part and am exponentially decaying attractive part. Our modeling results suggest that the system may have a complicated phase behavior, including a quasi-crystalline phase at low ionic screening, a disordered phase and, in addition, a possible “clotting” agglomerate phase at high screening where the photosystems tend to clot together. The relevance of the observed phenomena to the stacking of thylakoid membranes is discussed.
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  • 14
    ISSN: 1432-1327
    Keywords: Catalase ; Manganese cluster ; Nitric oxide ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Thermus thermophilus catalase. Flash fluorescence studies indicate that the S3 state of the OEC in the presence of ca. 0.6 mM NO is reduced to the S1 with an apparent halftime of ca. 0.4 s at about 18 °C, compared with a biphasic decay, with approximate halftimes of 28 s for S3 to S2 and 140 s for S2 to S1 in the absence of NO. Under similar conditions the S2 state is reduced by NO to the S1 state with an approximate halftime of 2 s. These results extend a recent study indicating a slow reduction of the S1 state at −30°C, via the S0 and S−1 states, to a Mn(II)-Mn(III) state resembling the corresponding state in catalase. The reductive mode of action of NO is repeated with the di-Mn cluster of catalase: the Mn(III)-Mn(III) redox state is reduced to the Mn(II)-Mn(II) state via the intermediate Mn(II)-Mn(III) state. The kinetics of this reduction suggest a decreasing reduction potential with decreasing oxidation state, similar to what is observed with the active states of the OEC. What is unique about the OEC is the rapid interaction of NO with the S3 state of the OEC, which is compatible with a metalloradical character of this state.
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  • 15
    ISSN: 1573-1561
    Keywords: Insect pheromones ; pheromone emission ; aggressive chemical mimicry ; predation ; allomone ; Araneae ; Araneidae ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The adult female bolas spider Mastophora hutchinsoni feeds exclusively on attracted males of a few moth species. This exclusivity and the behavior of the approaching moths suggest that the spider aggressively mimics the sex pheromones of its prey species. Males of the bristly cutworm, Lacinipolia renigera, are a major prey of this spider, accounting for about two thirds of the biomass of prey consumed. Female bristly cutworms produce a pheromone blend consisting of (Z)-9-tetradecenyl acetate (Z9–14 : Ac) and (Z,E)-9,12-tetradecenyl acetate (ZE-9,12–14 : Ac). To determine if M. hutchinsoni females mimic the sex pheromone components and blend ratio of L. renigera, we collected volatiles from hunting adult female spiders and analyzed them with gas chromatography–electroantennographic detection (GC-EAD) and gas chromatography–mass spectrometry (GC-MS). GC-EAD analysis of volatile collections, using a male bristly cutworm antenna as the detector and two capillary columns of different polarities, revealed the presence of peaks with retention times (R ts) identical to Z9–14 : Ac and ZE-9,12– 14 : Ac. The mass spectrum of a peak with R t of Z9–14 : Ac was identical to the mass spectrum of the synthetic equivalent. There was an insufficient quantity of the compound with R t of ZE-9,12–14 : Ac to get a full spectrum, but selective detection of ions at m/z 61 and 192 at the correct R t supported the identification. On average, the blend collected from spiders contained 54.8 ± 20.8 (SE) pg/min of Z9–14 : Ac and 2.5 ± 1.7 (SE) pg/min of ZE-9,12–14 : Ac. The latter, on average, comprised 2.6 ± 0.7% of the total, which is similar to the blend ratio emitted by bristly cutworm females. Our results indicate that the adult female M. hutchinsoni produces an allomone blend that mimics not only the composition, but also the blend ratio, of the sex pheromone of a major prey species.
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  • 16
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    Journal of chemical ecology 26 (2000), S. 1983-1990 
    ISSN: 1573-1561
    Keywords: Setora nitens ; Setothosea asigna ; nettle caterpillar ; Limacodidae ; Lepidoptera ; sex pheromone ; (Z)-9-dodecenal ; (Z)-9,11-dodecadienal ; (E)-9-dodecenal ; (E)-9,11-dodecadienal ; oil palm ; Elaeis guineensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone gland extracts of female nettle caterpillars, Setora nitens, revealed four compounds that consistently elicited responses from male moth antennae. Retention indices on three fused silia columns (DB-5, DB-23, and DB-210) of two EAD-active compounds were almost identical to those of (E)-9-dodecenal (E9–12 : Ald) and (E)-9,11-dodecadienal (E9,11–12 : Ald), two pheromone components previously identified in congeneric Setothosea asigna. However, comparative GC, GC-EAD, and GC-mass spectrometry of extracted S. nitens compounds and authentic standards revealed that the candidate pheromone components were (Z)-9-dodecenal (Z9–12 : Ald) and (Z)-9,11-dodecadienal (Z9,11–12 : Ald). The two other EAD-active compounds in pheromone gland extracts proved to be the corresponding alcohols to these aldehydes. In field-trapping experiments in Tawau, Malaysia, synthetic Z9–12 : Ald and Z9,11–12 : Ald at a 1 : 1 ratio, but not singly, attracted male S. nitens. Attractiveness of these two aldehydes could not be enhanced through the addition of their corresponding alcohols. Whether these differences in pheromone biology and chemistry between S. nitens and S. asigna are sufficient to prevent cross-attraction of heterospecific males or whether nonpheromonal mechanisms are required to maintain reproductive isolation is currently being studied.
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  • 17
    ISSN: 1432-0762
    Keywords: Key words Copulation duration ; Explosive mating system ; Ejaculate size ; Lepidoptera ; Mating history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The mating system of the Australian lycaenid butterfly, Jalmenus evagoras, is highly unusual compared to most other Lepidoptera. Characteristics of this system, which has been termed an ’explosive mating strategy,’ include the formation of an intensely competitive mating aggregation of males, a highly male biased operational sex ratio, a lack of discrimination and mate choice by both sexes, a high variance in male mating success, and female monogamy. In this study, we tested the hypothesis that multiple mating by males imposes physiological costs resulting in smaller spermatophores, and that this results in a fitness cost to females. We found that male J. evagoras transferred only 2.2% of their eclosion weight during their first mating, consistent with the hypothesis that males of monandrous species produce a relatively small investment. The wet weight of the ejaculate declined by an average of 27% at the second mating and the dry weight by 29%, and an intermating interval of 5–9 days was needed for the ejaculate to return to the size at the first mating, regardless of male size or age. Wet ejaculate mass increased proportionally with male size, though dry mass was proportionally larger in smaller males. Ejaculate mass tended to increase with male age at both first and second matings. Female characteristics, in general, did not affect ejaculate mass, although the wet weight of the ejaculate was positively associated with female weight at the second mating. Copulation duration increased from 2.4 h to approximately 3 h at the second mating, and to over 4 h at the third and fourth matings. Fecundity was positively correlated with female size but not with mating history, copulation duration, or any other characteristics measured for either males or females. Female longevity declined significantly as the number of times the male partner had previously mated increased. We conclude that despite the small male investment in ejaculate, the costs of multiple mating may nonetheless be significant, as indicated by the reduction in ejaculate mass, an increase in copulation duration, and reduction in female lifespan with increasing mating number.
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  • 18
    ISSN: 1573-5079
    Keywords: EPR ; fluorescence ; Photosystem II ; thermoluminescence ; thylakoid membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recently, a novel procedure to isolate a highly pure and active Photosystem II preparation directly from thylakoid membranes, referred to as PS II–LHC II supercomplex, was reported [Eshaghi et al. (1999) FEBS Lett 446: 23–26]. In addition to the reaction center core proteins, the supercomplex contains all the extrinsic proteins of the oxygen evolving complex and a set of chlorophyll a/b binding proteins. In this paper, the functional properties of this isolated supercomplex are further characterized by using EPR spectroscopy, thermoluminescence, fluorescence relaxation kinetics and flash induced oxygen yield measurements. The PS II–LHC II supercomplex contains, in addition to QA and QB, a small pool of plastoquinone (PQ). Although the isolated complex is no longer membrane bound, it has preserved functional characteristics of a well defined PS II preparation with the exception of some modification of QB sites.
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  • 19
    ISSN: 1573-5079
    Keywords: CF0F1 ; cytochrome b 6 f ; electron microscopy ; grana ; Photosystem I ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A biochemical and structural analysis is presented of fractions that were obtained by a quick and mild solubilization of thylakoid membranes from spinach with the non-ionic detergent n-dodecyl-α,D-maltoside, followed by a partial purification using gel filtration chromatography. The largest fractions consisted of paired, appressed membrane fragments with an average diameter of about 360 nm and contain Photosystem II (PS II) and its associated light-harvesting antenna (LHC II), but virtually no Photosystem I, ATP synthase and cytochrome b 6 f complex. Some of the membranes show a semi-regular ordering of PS II in rows at an average distance of about 26.3 nm, and from a partially disrupted grana membrane fragment we show that the supercomplexes of PS II and LHC II represent the basic structural unit of PS II in the grana membranes. The numbers of free LHC II and PS II core complexes were very high and very low, respectively. The other macromolecular complexes of the thylakoid membrane occurred almost exclusively in dispersed forms. Photosystem I was observed in monomeric or multimeric PS I-200 complexes and there are no indications for free LHC I complexes. An extensive analysis by electron microscopy and image analysis of the CF0F1 ATP synthase complex suggests locations of the δ (on top of the F1 headpiece) and ∈ subunits (in the central stalk) and reveals that in a substantial part of the complexes the F1 headpiece is bended considerably from the central stalk. This kinking is very likely not an artefact of the isolation procedure and may represent the complex in its inactive, oxidized form.
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  • 20
    ISSN: 1573-5079
    Keywords: Photosystem II ; pheophytin a ; pigment exchange ; reaction centre ; 131-deoxo-131-hydroxy pheophytin a
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pheophytin a (Pheo) in Photosystem II reaction centres was exchanged for 131-deoxo-131-hydroxy-pheophytin a (131-OH-Pheo). The absorption bands of 131-OH-Pheo are blue-shifted and well separated from those of Pheo. Two kinds of modified reaction centre preparations can be obtained by applying the exchange procedure once (RC1×) or twice (RC2×). HPLC analysis and Pheo QX absorption at 543 nm show that in RC1× about 50% of Pheo is replaced and in RC2× about 75%. Otherwise, the pigment and protein composition are not modified. Fluorescence emission and excitation spectra show quantitative excitation transfer from the new pigment to the emitting chlorophylls. Photoaccumulation of Pheo− is unmodified in RC1× and decreased only in RC2×, suggesting that the first exchange replaces the inactive and the second the active Pheo. Comparing the effects of the first and the second replacement on the absorption spectrum at 6 K did not reveal substantial spectral differences between the active and inactive Pheo. In both cases, the absorption changes in the QY region can be interpreted as a combination of a blue shift of a transition at 684 nm, a partial decoupling of chlorophylls absorbing at 680 nm and a disappearance of Pheo absorption in the 676-680 nm region. No absorption decrease is observed at 670 nm for RC1× or RC2×, showing that neither of the two reaction centre pheophytins contributes substantially to the absorption at this wavelength.
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  • 21
    ISSN: 1573-5079
    Keywords: cyanobacteria ; excitation energy transfer ; membrane proteins assembly ; Photosystem I ; Photosystem II ; spillover ; state transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The fluorescence profile of Photosystem I/Photosystem II mixtures in different solvent systems shows that both non-hydrophobic and hydrophobic interactions govern their association and control energy transfer from Photosystem II to Photosystem I. The non-hydrophobic interactions lead to a highly efficient excitation energy transfer from Photosystem II to Photosystem I. In view of this, we propose that similar non-hydrophobic interactions, between the Photosystem II and Photosystem I peripheral proteins, also play a significant role in their association in thylakoids that control state transitions in cyanobacteria.
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  • 22
    ISSN: 1573-5079
    Keywords: energy dissipation ; Photosystem I ; Photosystem II ; spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The light-induced chlorophyll (Chl) fluorescence decline at 77 K was investigated in segments of leaves, isolated thylakoids or Photosystem (PS) II particles. The intensity of chlorophyll fluorescence declines by about 40% upon 16 min of irradiation with 1000 μmol m−2 s−1 of white light. The decline follows biphasic kinetics, which can be fitted by two exponentials with amplitudes of approximately 20 and 22% and decay times of 0.42 and 4.6 min, respectively. The decline is stable at 77 K, however, it is reversed by warming of samples up to 270 K. This proves that the decline is caused by quenching of fluorescence and not by pigment photodegradation. The quantum yield for the induction of the fluorescence decline is by four to five orders lower than the quantum yield of QA reduction. Fluorescence quenching is only slightly affected by addition of ferricyanide or dithionite which are known to prevent or stimulate the light-induced accumulation of reduced pheophytin (Pheo). The normalised spectrum of the fluorescence quenching has two maxima at 685 and 695 nm for PS II emission and a plateau for PS I emission showing that the major quenching occurs within PS II. ‘Light-minus-dark’ difference absorbance spectra in the blue spectral region show an electrochromic shift for all samples. No absorbance change indicating Chl oxidation or Pheo reduction is observed in the blue (410–600 nm) and near infrared (730–900 nm) spectral regions. Absorbance change in the red spectral region shows a broad-band decrease at approximately 680 nm for thylakoids or two narrow bands at 677 and 670–672 nm for PS II particles, likely resulting also from electrochromism. These absorbance changes follow the slow component of the fluorescence decline. No absorbance changes corresponding to the fast component are found between 410 and 900 nm. This proves that the two components of the fluorescence decline reflect the formation of two different quenchers. The slow component of the light-induced fluorescence decline at 77 K is related to charge accumulation on a non-pigment molecule of the PS II complex.
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  • 23
    ISSN: 1573-5079
    Keywords: FTIR ; manganese cluster ; oxygen-evolving complex ; Photosystem II ; plastoquinone ; vibrational spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In this communication, we report our progress on the development of low-frequency Fourier transform infrared (FTIR) spectroscopic techniques to study metal-substrate and metal-ligand vibrational modes in the Photosystem II/oxygen-evolving complex (PS II/OEC). This information will provide important structural and mechanistic insight into the OEC. Strong water absorption in the low-frequency region (below 1000 cm−1), a lack of suitable materials, and temperature control problems have limited previous FTIR spectroscopic studies of the OEC to higher frequencies (〉1000 cm−1). We have overcome these technical difficulties that have blocked access to the low-frequency region and have developed successive instruments that allow us to move deeper into the low-frequency region (down to 350 cm−1), while increasing both data accumulation efficiency and S/N ratio. We have detected several low-frequency modes in the S2/S1spectrum that are specifically associated with these two states. Our results demonstrate the utility of FTIR techniques in accessing low-frequency modes in Photosystem II and in proteins generally.
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  • 24
    ISSN: 1573-5079
    Keywords: chlorophyll ; energy quenching ; fluorescence ; LIDAR ; photochemistry ; photosynthesis ; Photosystem II ; phytoplankton ; pump and probe ; remote sensing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Initial results of the airborne LIDAR measurement of photochemical quantum yield, ΦPo, and functional absorption cross-section, σPS II, of Photosystem II (PS II) are reported. NASA's AOL3 LIDAR was modified to implement short-pulse pump-and-probe (SP-P&P) LIDAR measurement protocol. The prototype system is capable of measuring a pump-induced increase in probe-stimulated chlorophyll fluorescence, ΔF/Fsat, along with the acquisition of `conventional' LIDAR-fluorosensor products from an operational altitude of 150 m. The use of a PS II sub-saturating probe pulse increases the response signal but also results in excessive energy quenching (EEQ) affecting the ΔF/Fsat magnitude. The airborne data indicated up to a 3-fold EEQ-caused decline in ΔF/Fsat, and 2-fold variability in the EEQ rate constant over a spatial scale a few hundred kilometers. Therefore, continuous monitoring of EEQ parameters must be incorporated in the operational SP-P&P protocol to provide data correction for the EEQ effect. Simultaneous airborne LIDAR measurements of ΦPo and σPS II with EEQ correction were shown to be feasible and optimal laser excitation parameters were determined. Strong daytime ΔF/Fsat decline under ambient light was found in the near-surface water layer over large aquatic areas. An example of SP-P&P LIDAR measurement of phytoplankton photochemical and fluorescent characteristics in the Chesapeake Bay mouth is presented. Prospects for future SP-P&P development and related problems are discussed.
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  • 25
    ISSN: 1573-5079
    Keywords: Fourier transform infrared spectroscopy ; Mn-cluster ; oxygen evolution ; photosynthesis ; Photosystem II ; vibrational spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The S2 state of the oxygen-evolving Mn-cluster of Photosystem II (PS II) is known to have different forms that exhibit the g =2 multiline and g = 4.1 EPR signals. These two spin forms are interconvertible at 〉 200 K and the relative amplitudes of the two signals are dependent on the species of cryoprotectant and alcohol contained in the medium. Also, it was recently found that the mutiline form can be converted to the g = 4.1 form by absorption of near-infrared light by the Mn-cluster itself at around 150 K [Boussac et al. (1996) Biochemistry 35: 6984–6989]. We have used light-induced Fourier transform infrared (FTIR) difference spectroscopy to study the structural difference in these two S2 forms. FTIR difference spectra for S2/S1 as well as for S2QA -/S1QA measured at cryogenic temperatures using PS II membranes in the presence of various cryoprotectants, and monohydric alcohols did not show any specific differences except for intensities of amide I bands, which were larger when ethylene glycol or glycerol was present in addition to sucrose. This result was interpreted due to more flexible movement of the protein backbones upon S2 formation with a higher cryoprotectant content. Light-induced difference spectra measured at 150 K using either blue light without near-infrared light or red plus near-infrared light also did not show any detectable difference. In addition, a different spectrum upon near-infrared illumination at 150 K of the PS II sample in which the S2 state had been photogenerated at 200 K exhibited no meaningful signals. These results indicate that the two S2 forms that give rise to the multiline and g = 4.1 signals have only minor differences, if any, in the structures of amino-acid ligands and polypeptide backbones. This conclusion suggests that conversion between the two spin states is caused by a spin-state transition in the Mn(III) ion rather than valence swapping within the Mn-cluster that would considerably affect the vibrations of ligands.
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  • 26
    ISSN: 1573-5079
    Keywords: chlorophyll ; fluorescence ; LIDAR ; photosynthesis ; Photosystem II ; pump and probe ; remote sensing ; singlet-singlet quenching ; singlet-triplet quenching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The development of a technique for laser measurement of fPhotosystem II (PS II) photochemical characteristics of phytoplankton and terrestrial vegetation from an airborne platform is described. Results of theoretical analysis and experimental study of pump-and-probe measurement of the PS II functional absorption cross-section and photochemical quantum yield are presented. The use of 10 ns probe pulses of PS II sub-saturating intensity provides a significant, up to 150-fold, increase in the fluorescence signal compared to conventional `weak-probe' protocol. Little effect on the fluorescence yield from the probe-induced closure of PS II reaction centers is expected over the short pulse duration, and thus a relatively intense probe pulse can be used. On the other hand, a correction must be made for the probe-induced carotenoid triplet quenching and singlet-singlet annihilation. A Stern-Volmer model developed for this correction assumes a linear dependence of the quenching rate on the laser pulse fluence, which was experimentally validated. The PS II saturating pump pulse fluence (532 nm excitation) was found to be 10 and 40 μmol quanta m−2 for phytoplankton samples and leaves of higher plants, respectively. Thirty μs was determined as the optimal delay in the pump-probe pair. Our results indicate that the short-pulse pump-and-probe measurement of PS II photochemical characteristics can be implemented from an airborne platform using existing laser and LIDAR technologies.
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  • 27
    ISSN: 1573-5079
    Keywords: electron transport ; herbicides ; novel triazines ; O-J-I-P fluorescence transient ; Photosystem II ; resistance ; thylakoid membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nine novel 2-benzylamino-1,3,5-triazines on photosynthetic reactions were measured in thylakoids isolated from wild-type and atrazine-resistant plants of Chenopodium album. The resistant plants have a mutation of serine for glycine at position 264 of the D1 protein. The measurement of oxygen evolution and chlorophyll a fluorescence induction indicated a 2–4-fold stronger inhibition by the 6-trifluoromethyl analogues of Photosystem II-dependent electron flow than atrazine. Analogues having a 6-methyl-, 6-monofluoromethyl or 6-difluoromethyl substitution were weak inhibitors, indicating that the 6-trifluoro group is very important for strong inhibition. All the nine novel 2-benzylamino-1,3,5-triazines were almost as active in wild-type as in atrazine-resistant thylakoids, indicating that the benzylamino substitution may be important for the lack of resistance in the atrazine-resistant plants.
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  • 28
    ISSN: 1573-5079
    Keywords: electron paramagnetic resonance ; extrinsic proteins ; manganese cluster ; oxygen evolution ; photosynthesis ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three extrinsic proteins (PsbO, PsbP and PsbQ), with apparent molecular weights of 33, 23 and 17 kDa, bind to the lumenal side of Photosystem II (PS II) and stabilize the manganese, calcium and chloride cofactors of the oxygen evolving complex (OEC). The effect of these proteins on the structure of the tetramanganese cluster, especially their possible involvement in manganese ligation, is investigated in this study by measuring the reported histidine-manganese coupling [Tang et al. (1994) Proc Natl Acad Sci USA 91: 704–708] of PS II membranes depleted of none, two or three of these proteins using ESEEM (electron spin echo envelope modulation) spectroscopy. The results show that neither of the three proteins influence the histidine ligation of manganese. From this, the conserved histidine of the 23 kDa protein can be ruled out as a manganese ligand. Whereas the 33 and 17 kDa proteins lack conserved histidines, the existence of a 33 kDa protein-derived carboxylate ligand has been posited; our results show no evidence for a change of the manganese co-ordination upon removal of this protein. Studies of the pH-dependence of the histidine–manganese coupling show that the histidine ligation is present in PS II centers showing the S2 multiline EPR signal in the pH-range 4.2–9.5.
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  • 29
    ISSN: 1573-5028
    Keywords: cyanobacteria ; D1 ; D2 ; Photosystem II ; psbA ; Synechocystis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The turnover of the D1 and D2 proteins of Photosystem II (PSII) has been investigated by pulse-chase radiolabeling in several strains of the cyanobacterium Synechocystis PCC 6803 containing different types and levels of the psbA transcript. Strains lacking psbA1 and psbA3 gene and containing high levels of the psbA2 transcript showed the selective synthesis of D1 whose degradation could be slowed down by the protein synthesis inhibitor lincomycin. In contrast, in strains containing just the psbA3 gene, the intensity of the D1 protein labeling was lower and labeling of the D2 and CP43 proteins was stimulated in comparison to the psbA2-containing strains. In addition, the rate and selectivity of the D1 degradation and its dependence on the presence of lincomycin was proportional to the level of the psbA3 transcript in the particular strain. Consequently, there was parallel, lincomycin-independent and slowed-down breakdown of the D1 and D2 proteins in strains with the lowest level of psbA3 transcript. These results are discussed in terms of a model in which the rate of D1 and D2 degradation in cyanobacteria is affected not only by the rate of PSII photodamage, but also by the availability of newly synthesized D1 protein. Moreover, the comparison of the non-oxygen-evolving D1 mutants D170A** and Y161F*** differing by the presence of tyrosine Z has indicated a minor role of the oxidized form of this secondary PSII electron donor in the donor side mechanism of D1 and D2 protein breakdown.
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  • 30
    ISSN: 1573-1561
    Keywords: Insecta ; tobacco hornworm ; Manduca sexta ; tobacco ; Nicotiana tabacum ; ozone ; weather fleck ; Lepidoptera ; Sphingidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Tobacco plants, Nicotiana tabacum were grown under different levels of ozone (O3) in open-top chambers. Ozone concentrations were established by charcoal filtration, which reduced O3 to approximately one-half ambient, or by the addition of O3 to unfiltered air to increase concentrations to approximately 1.4 or 1.7 times ambient O3. Survival of tobacco hornworm, Manduca sexta, larvae was increased when second instars were fed tobacco leaves grown in chambers with elevated levels of O3. Second instars also gained significantly more weight when they were fed for one week on plants exposed to elevated levels of O3 than when they were fed plants grown in charcoal-filtered air. Ozone-treated tobacco plants had higher levels of total nitrogen (primarily reduced nitrogen) and soluble carbohydrates (sugars), and lower levels of leaf-surface components, starch, nicotine, and rutin. Increased survival and growth response of hornworm larvae to elevated O3 levels in these experiments suggests that similar responses could occur in the southeastern US tobacco production areas where O3 levels can be high enough to injure tobacco plants.
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  • 31
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Tortricidae ; Enarmonia formosana ; cherry bark tortrix ; kairomone ; host selection ; foraging behavior ; plant volatiles ; nonhost volatiles ; repellency/inhibition ; oviposition deterrence ; hexanol ; benzyl alcohol ; nonanal ; decanal ; α-pinene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We tested the hypothesis that males and females of the cherry bark tortrix (CBT), Enarmonia formosana, antennally perceive and behaviorally respond to volatiles from nonhost plants. Volatiles from flowering cherry trees, Prunus serrulata Kwanzan, and from nonhost trees, including trembling aspen, Populus tremuloides, grand fir, Abies grandis, Norway spruce, Picea abies, and Scots pine, Pinus sylvestris, were captured on Porapak Q and extracts analyzed by coupled gas chromatographic–electroantennographic detection (GC-EAD). Compounds that elicited responses from male and female antennae were identified by coupled GC–mass spectrometry (MS) and by comparative GC-MS and GC-EAD with authentic standards. In field cage and field experiments, nonanal from aspen trees and (±)-α-pinene from coniferous trees were effective in reducing captures of male CBT in pheromone-baited traps and deterring oviposition by female CBT on cherry blocks. Recognition of nonhost volatiles, such as nonanal and α-pinene, may allow male and/or female CBT to avoid trees that provide inadequate concealment from predators during calling, resting, and copulation and that are unsuitable for oviposition and development of offspring. Nonhost volatiles may also be exploited for control of CBT by disrupting both mate- and host-finding.
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  • 32
    ISSN: 1573-1561
    Keywords: Field trapping ; pheromone ; Lepidoptera ; Gelechiidae ; Tuta absoluta ; South American tomato moth ; Scrobipalpuloides absoluta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Field evaluations demonstrate that the addition of the minor pheromone component (3E,8Z)-tetradecadien-1-yl acetate to the major component (3E,8Z,11Z)-tetradecatrien-1-yl acetate does not significantly increase the trap catches of Tuta absoluta males in the field. The triene acetate itself is highly attractive, catching about 869 ± 255 males per trap in three consecutive nights. The addition of two isomers of the minor component (3E,8Z)-tetradecadien-1-yl acetate, (3E,11Z)-tetradecadienyl-yl acetate and (8Z,11Z)-tetradecadien-1-yl acetate, to the major component (3E,8Z,11Z)-tetradecatrien-1-yl acetate also did not significantly alter the number of the males caught in the traps.
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  • 33
    ISSN: 1573-1561
    Keywords: Scoliopteryx libatrix ; Noctuidae ; Lepidoptera ; sex pheromone ; methylalkene ; (6Z13)-methylheneicosene ; electroantennogram ; field test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The major component of the female-produced sex pheromone of Scoliopteryx libatrix has been characterized by chemical analysis, synthesis, electrophysiological studies and field tests as (6Z,13)-methylheneicosene, probably the 13S-isomer. This is the first example of a branched chain alkene as a sex pheromone in the Noctuidae and is markedly different from the pheromones of other members of the family. The systematic position of S. libatrix, belonging to a monotypic genus of a one-member subfamily within the Noctuidae, may reflect the unusual structure of the sex pheromone.
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  • 34
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Limacodidae ; Darna trima ; Darna bradleyi ; Setothosea asigna ; Setora nitens ; nettle caterpillars ; oil palm ; sex pheromone ; 2-methylbutyl (E)-7,9-decadienoate ; (E)-2-hexenyl (E)-7,9-decadienoate ; methyl (E)-7,9-decadienoate ; isobutyl (E)-7,9-decadienoate ; (E)-9dodecenal ; (E)-9,11-dodecadienal ; (Z)-9-dodecenal ; (Z)-9,11-dodecadienal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract This study was undertaken to identify sex pheromone components of nettle caterpillars Darna trima and Darna bradleyi (Lepidoptera: Limacodidae) whose larvae defoliate oil palm, Elaeis guineensis, in southeast Asia. Coupled gas chromatographic–electroantennographic detection (GCEAD) analyses of pheromone gland extracts revealed two antennally active compounds produced by female D. trima and two by female D. bradleyi. Molecular structures of these candidate pheromone components were identified by electron-impact and chemical-ionization mass spectrometry; retention-index calculations on DB-5, DB-23, and DB-210 columns; microanalytical treatments, as well as syntheses of "auxilliary" compounds that facilitated identification of the compounds. The compounds from D. trima were 2-methylbutyl (E)-7,9-decadienoate (A) and (E)-2-hexenyl (E)-7,9decadienoate (B); from D. bradleyi we identified methyl (E)-7,9-decadienoate (C), and isobutyl (E)-7,9-decadienoate (D). In field experiments in Malaysia, (S)-2-methylbutyl (E)-7,9-decadienoate (SA) in combination with B proved to be essential and synergistic pheromone components for attraction of male D. trima. (R)-2-Methylbutyl (E)-7,9-decadienoate (RA) had no behavioral activity. Compound D singly attracted male D. bradleyi, but addition of C to D at a 1 : 10 ratio significantly enhanced attractiveness of the bait. Synthetic pheromone blends were more effective trap baits than unmated female moths and could be developed for monitoring populations of D. trima and D. bradleyi in Asian oil palm plantations.
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  • 35
    ISSN: 1573-5079
    Keywords: electron spin-lattice relaxation rate ; manganese ; oxygen-evolving complex ; photosynthesis ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pulsed EPR inversion recovery sequence has been utilized to monitor the temperature dependence of the electron spin-lattice relaxation rate of the Mn cluster of the Photosystem II oxygen evolving complex poised in a variety of S 2 state forms giving rise to g = 2 multiline EPR signals. A previous study (Lorigan and Britt (1994) Biochemistry 33: 12072–12076) showed that for PS II membranes treated with 5% ethanol, the S 2 state Mn cluster relaxes via the Orbach spin-lattice relaxation mechanism, where the relaxation is enhanced via phonon scattering off an excited state spin manifold, in this case at an energy of Δ = 36.5 cm−1 above the S = 1/2 ground state giving rise to the multiline EPR signal. Parallel experiments are reported for PS II membranes with 5% methanol, treated with ammonia, and following short and long term dark adaptation. In each case, the temperature dependence of the electron spin-lattice relaxation rate is consistent with Orbach relaxation, and the range of excited state energies is relatively narrow (33.8 cm−1 ≤ Δ ≤ 39.7 cm−1). In addition, short term dark adapted (6 min, ‘active state’) PS II membranes show biphasic recovery traces which indicate that a minority fraction of the oxygen evolving complexes are trapped in a form with greatly slowed spin-lattice relaxation.
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  • 36
    ISSN: 1573-5079
    Keywords: chlororespiration ; pheophytin a ; photosynthesis ; Photosystem II ; potato ; tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Increases in the chlorophyll fluorescence Fo (dark level fluorescence) during heat treatments were studied in various higher plants. Besides the dissociation of light-harvesting chlorophyll a/b protein complexes from the reaction center complex of PS II and inactivation of PS II, dark reduction of QA via plastoquinone (PQ) seemed to be related to the Fo increase at high temperatures. In potato leaves or green tobacco cultured cells, a part of the Fo increase was quenched by light, reflecting light-induced oxidation of QA - which had been reduced in the dark at high temperatures. Appearance of the Fo increase due to QA reduction depended on the plant species, and the mechanisms for this are proposed. The reductants seemed to be already present and formed by very brief illumination of the leaves at high temperatures. A ndhB-less mutant of tobacco showed that complex I type NAD(P)H dehydrogenase is not involved in the heat-induced reduction of QA. Quite strong inhibition of the QA reduction by diphenyleneiodonium suggests that a flavoenzyme is one of the electron mediator to PQ from the reductant in the stroma. Reversibility of the heat-induced QA reduction suggests that an enzyme(s) involved is activated at high temperatures and mostly returns to an inactive form at room temperature (25 °C).
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  • 37
    ISSN: 1573-5079
    Keywords: cyanobacteria ; IdiA ; oxidative stress ; Photosystem II ; PsbO ; Synechococcus sp. PCC 7942 and PCC 6301
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Synechococcus sp. strains PCC 7942 and PCC 6301 contain a 35 kDa protein called IdiA (Iron deficiency induced protein A) that is expressed in elevated amounts under Fe deficiency and to a smaller extent also under Mn deficiency. Absence of this protein was shown to mainly damage Photosystem II. To decide whether IdiA has a function in optimizing and/or protecting preferentially either the donor or acceptor side reaction of Photosystem II, a comparative analysis was performed of Synechococcus sp. PCC 7942 wild-type, the IdiA-free mutant, the previously constructed PsbO-free Synechococcus PCC 7942 mutant and a newly constructed Synechococcus PCC 7942 double mutant lacking both PsbO and IdiA. Measurements of the chlorophyll fluorescence and determinations of Photosystem II activity using a variety of electron acceptors gave evidence that IdiA has its main function in protecting the acceptor side of Photosystem II. Especially, the use of dichlorobenzoquinone, preferentially accepting electrons from QA, gave a decreased O2 evolving activity in the IdiA-free mutant. Investigations of the influence of hydrogen peroxide treatment on cells revealed that this treatment caused a significantly higher damage of Photosystem II in the IdiA-free mutant than in wild-type. These results suggest that although the IdiA protein is not absolutely required for Photosystem II activity in Synechococcus PCC 7942, it does play an important role in protecting the acceptor side against oxidative damage.
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  • 38
    ISSN: 1573-5079
    Keywords: Chlorophyll fluorescence ; non-photochemical quenching ; Photosystem II ; thylakoid membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The efficiency of oxidized endogenous plastoquinone-9 (PQ-9) as a non-photochemical quencher of chlorophyll fluorescence has been analyzed in spinach thylakoids and PS II membrane fragments isolated by Triton X-100 fractionation of grana stacks. The following results were obtained: (a) After subjection of PS II membrane fragments to ultrasonic treatment in the presence of PQ-9, the area over the induction curve of chlorophyll fluorescence owing to actinic cw light increases linearly with the PQ-9/PS II ratio in the reconstitution assay medium; (b) the difference of the maximum fluorescence levels, Fmax, of the induction curves, measured in the absence and presence of DCMU, is much more pronounced in PS II membrane fragments than in thylakoids; (c) the ratio Fmax(-DCMU)/Fmax(+DCMU) increases linearly with the content of oxidized PQ-9 that is varied in the thylakoids by reoxidation of the pool after preillumination and in PS II membrane fragments by the PQ-9/PS II ratio in the reconstitution assay; (d) the reconstitution procedure leads to tight binding of PQ-9 to PS II membrane fragments, and PQ-9 cannot be replaced by other quinones; (e) the fluorescence quenching by oxidized PQ-9 persists at low temperatures, and (f) oxidized PQ-9 preferentially affects the F695 of the fluorescence emission spectrum at 77 K. Based on the results of this study the oxidized PQ-9 is inferred to act as a non-photochemical quencher via a static mechanism. Possible implications for the nature of the quenching complex are discussed.
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  • 39
    ISSN: 1573-5079
    Keywords: Ca2+-depletion ; charge recombination ; photoinhibition ; Photosystem II ; QA midpoint potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Inhibition of Photosystem II (PS II) activity induced by continuous light or by saturating single turnover flashes was investigated in Ca2+-depleted, Mn-depleted and active PS II enriched membrane fragments. While Ca2+- and Mn-depleted PS II were more damaged under continuous illumination, active PS II was more susceptible to flash-induced photoinhibition. The extent of photoinactivation as a function of the duration of the dark interval between the saturating single turnover flashes was investigated. The active centres showed the most photodamage when the time interval between the flashes was long enough (32 s) to allow for charge recombination between the S2 or S3 and QB − to occur. Illumination with groups of consecutive flashes (spacing between the flashes 0.1 s followed by 32 s dark interval) resulted in a binary oscillation of the loss of PS II-activity in active samples as has been shown previously (Keren N, Gong H, Ohad I (1995), J Biol Chem 270: 806–814). Ca2+- and Mn-depleted PS II did not show this effect. The data are explained by assuming that charge recombination in active PS II results in a back reaction that generates P680 triplet and thence singlet oxygen, while in Ca2+- and Mn-depleted PS II charge recombination occurs through a different pathway, that does not involve triplet generation. This correlates with an up-shift of the midpoint potential of QA in samples lacking Ca2+ or Mn that, in term, is predicted to result in the triplet generating pathway becoming thermodynamically less favourable (G.N. Johnson, A.W. Rutherford, A. Krieger, 1995, Biochim. Biophys. Acta 1229, 201–207). The diminished susceptibility to flash-induced photoinhibition in Ca2+- and Mn-depleted PS II is attributed at least in part to this mechanism.
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  • 40
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    Photosynthesis research 63 (2000), S. 195-208 
    ISSN: 1573-5079
    Keywords: charge separation ; disorder ; exciton interaction ; Photosystem II ; reaction center
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    Topics: Biology
    Notes: Abstract In this Minireview, we discuss a number of issues on the primary photosynthetic reactions of the green plant Photosystem II. We discuss the origin of the 683 and 679 nm absorption bands of the PS II RC complex and suggest that these forms may reflect the single-site spectrum with dominant contributions from the zero-phonon line and a pronounced ∼80 cm−1 phonon side band, respectively. The couplings between the six central RC chlorins are probably very similar and, therefore, a `multimer' model arises in which there is no `special pair' and in which for each realization of the disorder the excitation may be dynamically localized on basically any combination of neighbouring chlorins. The key features of our model for the primary reactions in PS II include ultrafast (〈500 fs) energy transfer processes within the multimer, `slow' (∼20 ps) energy transfer processes from peripheral RC chlorophylls to the RC multimer, ultrafast charge separation (〈500 fs) with a low yield starting from the singlet-excited `accessory' chlorophyll of the active branch, cation transfer from this `accessory' chlorophyll to a `special pair' chlorophyll and/or charge separation starting from this `special pair' chlorophyll (∼8 ps), and slow relaxation (∼50 ps) of the radical pair by conformational changes of the protein. The charge separation in the PS II RC can probably not be described as a simple trap-limited or diffusion-limited process, while for the PS II core and larger complexes the transfer of the excitation energy to the PS II RC may be rate limiting.
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  • 41
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    Plant molecular biology 44 (2000), S. 815-827 
    ISSN: 1573-5028
    Keywords: 4.1 kDa protein ; low-molecular-mass proteins ; oxygen evolution ; Photosystem II ; PSII ; PsbX
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The psbX gene (sml0002) coding for a 4.1 kDa protein in Photosystem II of plants and cyanobacteria was deleted in both wild type and in a Photosystem I-less mutant of the cyanobacterium Synechocystis sp. PCC 6803. Polymerase chain reaction and sequencing analysis showed that the mutants had completely segregated. Deletion of the PsbX protein does not seem to influence growth rate, electron transport or water oxidation ability. Whereas a high light induction of the psbX mRNA could be observed in wild type, deletion of the gene did not lead to high light sensibility. Light saturation measurements and 77K fluorescence measurements indicated a minor disconnection of the antenna in the deletion mutant. Furthermore, fluorescence induction measurements as well as immuno-staining of the D1 protein showed that the amount of Photosystem II complexes in the mutants was reduced by 30%. Therefore, PsbX does not seem to be necessary for the Photosystem II electron transport, but directly or indirectly involved in the regulation of the amount of functionally active Photosystem II centres in Synechocystis sp. PCC 6803.
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  • 42
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    Biodiversity and conservation 9 (2000), S. 479-486 
    ISSN: 1572-9710
    Keywords: biodiversity ; butterfly ; Ghana ; insect ; lagoon ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A variety of collection methods were used to inventory the insect diversity of the Muni-Pomadze Ramsar site along the Ghana coastline. A total of 75 butterfly species in five families were collected and identified. Twenty-six percent of the butterfly species were open country species. The butterflies were all typical of the coastal zone and no endangered or narrowly endemic species were recorded. The Muni-Pomadze site was also rich in other insect species (67 insect species belonging to 15 orders) as a result of the diverse terrestrial habitats surrounding the lagoon. Butterfly species composition changed with habitat indicating a fine-grained response by the butterfly communities to habitat changes. Data from long-term monitoring of butterfly communities at Muni-Pomadze could prove useful as indicators of habitat quality.
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  • 43
    ISSN: 1573-1561
    Keywords: Megalophanes viciella ; Psychidae ; Lepidoptera ; bagworm ; sex pheromone ; 1-methylethyl octanoate ; 2-propyl octanoate ; field tests
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Extracts obtained by rinsing the thorax and extracts from the tergal sex pheromone gland of females of the bagworm moth, Megalophanes viciella, as well as headspace samples from live animals, were analyzed to reveal the chemical structure of the pheromone. As a result, 1-methylethyl octanoate was established as a main sex pheromone component of this species. This was further confirmed by numerous catches of conspecific males in traps baited with this compound in Bulgaria and Roumania.
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  • 44
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    Journal of chemical ecology 26 (2000), S. 2549-2555 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Carposinidae ; (Z)-12–nonadecen-9–one ; chemical identification ; trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The female-produced sex pheromone of the New Zealand raspberry budmoth, Heterocrossa rubophaga, was investigated. Gas chromatographic–mass spectrometric analyses revealed the ketone, (Z)-12–nonadecen9–one (Z12–19–9–one). This compound had previously been found in extracts of the sex pheromone gland of the only other carposine moth for which a sex pheromone has been identified, Carposina niponensis, although its effect on the behavior of C. niponensis males had not been established. Field trapping trials in berry fruit gardens showed this compound to elicit high catches of male H. rubophaga, with the catch appearing to plateau (and perhaps decrease) above a dosage of 300 μg on a red rubber septum. In an analysis of an extract of female H. rubophaga sex pheromone glands, there was a suggestion that the homologous (Z)-7–eicosen-11–one, the known sex pheromone component of C. niponensis, was also present. However this could not be established unequivocally and, in a field trial, addition of a small amount of this compound to Z12–19–9–one resulted in no significant increase in trap catch relative to traps baited with Z12–19–9–one alone.
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  • 45
    ISSN: 1573-1561
    Keywords: Female sex pheromones ; Lepidoptera ; Geometridae ; Ennominae ; epoxynonadecene ; epoxynonadecadiene ; chiral epoxide ; chiral HPLC ; dimethyl disulfide adduct
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Biston robustum Butler, a polyphagous defoliator, multiplied on Hachijo-jima Island in 1997–1998. Based on GC-MS data of authentic standards, an analysis of a pheromone gland extract of the females indicated that it included (Z,Z)-6,9–nonadecadiene (I), (Z,Z,Z)-3,6,9–nonadecatriene (II), cis-(Z)-6,7–epoxy-9–nonadecene (III), and cis-(Z,Z)-6,7–epoxy-3,9–nonadecadiene (IV) in a ratio of 13 : 2 : 70 : 15. The structure of III was confirmed by a GC-MS analysis of another extract treated with dimethyl disulfide (DMDS). This epoxymonoene was successfully converted into the corresponding DMDS adduct that showed diagnostic ions fragmented at an epoxy ring and at thiomethoxy groups reflecting the position of an original double bond. Furthermore, the 6S,7R configuration was assigned for the epoxy ring of III by chiral HPLC analysis. Field examination of synthetic lures revealed that the two epoxy compounds (III and IV) with the 6S,7R configuration were essential components and that the two unsaturated hydrocarbons (I and II) showed a synergistic effect on male attraction.
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  • 46
    ISSN: 1573-8248
    Keywords: biological control ; blueberry ; egg parasitoid ; inundative release ; leafroller ; Lepidoptera ; Tortricidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inundative releases of Trichogramma minutum Riley were made in a commercialblueberry field in British Columbia, Canada, todetermine the extent of dispersal of adult wasps, andto determine whether complete parasitism of eggswithin egg masses of the target host [oblique-bandedleafroller (OBLR), Choristoneura rosaceana(Harris)] occurred. Three weekly releases of waspswere made from a single release point in the center ofeach field during the flight of first generation OBLRadults. Sticky trap, sentinel egg mass andtarget-host egg mass data all indicated only a limitedrange of dispersal of T. minutum within thefield. In addition, only partial parasitism of eggmasses of the target host occurred even in closeproximity to the release point. We discuss theimportance of determining the response of Trichogramma females to previously-parasitized eggswhen using Trichogramma wasps for biologicalcontrol of lepidopterous species that oviposit largeegg masses.
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  • 47
    ISSN: 1573-8248
    Keywords: bird predation ; forest ; interference ; Italy ; Lepidoptera ; pine processionary caterpillar ; parasitism,/kwd〉 ; Pinus ; Thaumetopoeidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The hoopoe (Upupa epops L.) is an insectivorousbird often preying on larvae and pupae of the pineprocessionary caterpillar (Thaumetopoeapityocampa Denis & Schiffermüller), the mostimportant defoliator of pines in Southern Europe andNorthern Africa. The first half of the breeding seasonof this migratory bird coincides with the pupal stageof the insect. Bird predation of pupae was quantifiedin two years in a Pinus nigra stand of northernItaly by periodic counting of the empty cocoons lefton the soil surface after extraction. The predationrate, estimated on 20 pupation sites representing thewhole stand, was 74.1% in 1993 and 68.3% in 1994.Predation was higher in the upper part of the soil andthen progressively decreased with increasing depth.The hoopoe may also prey on cocoons containing pupaeinfected by pathogenic fungi or parasitoids. Anexclosure experiment showed that the bird mayinterfere with these other mortality factors. Threepupal parasitoids, the ichneumonids Erigorgusfemorator Aubert and Coelichneumon rudis (Boyerde Fonscolombe) and the pteromalid Conomoriumpityocampae Graham, were significantly less frequentin the exposed sites. The fungus Beauveriabassiana (Balsamo) Vuillemin and the most abundantpupal parasitoid, Villa brunnea Becker (Diptera:Bombyliidae), caused the highest pupal mortality atboth protected and exposed sites. The bird seems to bean incompletely additive mortality factor acting onthe pest and it can also alter the relativemortalities imposed by the other natural enemies.
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  • 48
    ISSN: 1570-7458
    Keywords: host suitability ; acceptance ; biological control ; new associations ; Lepidoptera ; Pyralidae ; New World ; Old World ; stemborers ; Braconidae ; larval parasitoids ; Gramineae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The present study examined the acceptability and suitability of Old World stemborers (Chilo partellus and C. orichalcociliellus) for the development of New World parasitoids (Apanteles deplanatus and A. minator) and New World stemborers (Diatraea saccharalis and D. grandiosella) for the development of Old World parasitoids (Cotesia sesamiae, C. flavipes and C. chilonis). Results revealed that acceptance and suitability were high in old associations. In new associations, parasitoids accepted about 60% of the new association hosts. In addition, 10 out of 17 new associations were successful. Apanteles species appeared to be more physiologically host specific than Cotesia species. For example, two of four new association hosts were accepted by A. deplanatus and only one (D. saccharalis) was partially suitable for progeny development. Among the Cotesia species, Cotesia flavipes appeared to have a wider host range than the two other species. It attacked all hosts offered and successfully parasitized all but one (D. grandiosella). Diatraea saccharalis was accepted and was a suitable host for the development of all parasitoid species tested, whereas D. grandiosella was unsuitable for the development of four out of five parasitoid species tested. No clear pattern was observed as behavioral acceptance did not always agree with the pattern of physiological suitability. Implications of these findings for importation biological control of stemborers are discussed.
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  • 49
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    Entomologia experimentalis et applicata 91 (1999), S. 237-244 
    ISSN: 1570-7458
    Keywords: host plant range ; sex pheromone ; Ostrinia furnacalis ; Ostrinia latipennis ; Ostrinia nubilalis ; Ostrinia orientalis ; Ostrinia palustralis ; Ostrinia scapulalis ; Ostrinia zaguliaevi ; Ostrinia zealis ; Lepidoptera ; Pyralidae
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract To contribute to the understanding of the genus Ostrinia (Lepidoptera; Pyralidae) in Japan, we collected larvae of Ostrinia spp. from known host plants and plants not recorded as hosts, and we examined the morphology and sex pheromones of the adults obtained. Consequently, the host plant ranges of the 7 Ostrinia spp. in Japan were clarified, and the sex pheromones of the 5 species O. scapulalis, O. zealis, O. zaguliaevi, O. palustralis and O. latipennis were identified in addition to that of the Asian corn borer O. furnacalis. The phylogenetic relationships of Japanese Ostrinia spp., with reference to the European corn borer O. nubilalis, are discussed based on these findings and results of molecular phylogenetic analyses.
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  • 50
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    Entomologia experimentalis et applicata 91 (1999), S. 59-65 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Mamestra brassicae ; host-finding behaviour ; visual cues ; host-choice ; interaction ; odour ; volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The approach and landing responses of female Mamestra brassicae (L.) (Lepidoptera: Noctuidae) to visual cues from artificial plant leaves of different shapes and presence/absence of cabbage plant odour were investigated in a laboratory wind tunnel. The leaves were painted with cadmium yellow colour and observed under dim red light. Females showed oriented flight towards plant odours but landed significantly more often when the odour was presented with an artificial leaf. In three-choice tests, the shape of the leaf targets (circle, square or triangle) did not influence the female response. However, the size of the target did influence the insect response: the females preferred landing on square targets with sides of 5 or 10 cm rather than on the largest target, with sides of 15 cm. The orientation of the target influenced the insects' response: females landed significantly more often on the target positioned vertically than horizontally.
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  • 51
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    Entomologia experimentalis et applicata 91 (1999), S. 187-194 
    ISSN: 1570-7458
    Keywords: oviposition ; strategy ; catastrophe ; theory ; clutch ; Lepidoptera ; optimization ; dynamic ; bet hedging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We developed state-dependent life-history theory to explain the variance in clutch size decisions made by insect herbivores under a variety of ecological scenarios. An important aspect of our theory is explicit representation of the distribution of host quality and frequency of occurrence. Examination of the theory suggests that clutch size decisions can be highly non-linear with respect to host quality and variability. We then use our theory to explore the potential for bet-hedging strategies to evolve as a function of unpredictable catastrophic events that decimate entire clutches. Our analysis suggests that the benefits to employing such a strategy will frequently be outweighed by costs brought on by delayed oviposition.
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  • 52
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Yponomeutidae ; Plutella xylostella ; parasitoid ; Hymenoptera ; Braconidae ; Cotesia plutellae ; foraging behaviour ; wind tunnel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The braconid Cotesia plutellae is an important larval parasitoid of the diamondback moth (Plutella xylostella), a major pest of crucifers in the tropics and sub-tropics. The in-flight searching behaviour of C. plutellae was investigated in a wind tunnel and the close-range attack behaviour observed in cages. The relative importance of volatile stimuli emanating from the plant-host-complex, oilseed rape (Brassica napus) – P. xylostella, in the long-range attraction of C. plutellae was investigated. Plants that were mechanically damaged, or damaged by P. xylostella larvae, were attractive to the parasitoid. Host-damaged leaves remained attractive to the parasitoid after removal of the host larvae. These results indicate that C. plutellae predominantly uses plant derived stimuli in its in-flight searching behaviour. An oviposition experience or contact with a host-damaged leaf prior to the bioassay significantly increased the response to these volatile cues. The foraging behaviour of C. plutellae is compared with other braconid larval parasitoids attacking lepidopteran hosts on crucifers.
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  • 53
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    Entomologia experimentalis et applicata 92 (1999), S. 53-62 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; host selection ; correlation ; lightbrown apple moth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The polyphagous leafroller moth, Epiphyas postvittana, is a pest of many fruit crops in New Zealand. Since the larva is highly mobile, host selection in this insect may involve both the adult female and the larva. In order to test the relative importance of the adult female and the neonate larva in the selection of host plants, the ovipositional preferences of females, and the preferences or acceptances of neonate larvae towards 26 plant species, consisting of 15 plants considered hosts and 11 not considered hosts, were investigated. In the ovipositional tests, the mean preferences of females for hosts and non-hosts were very similar. In contrast, larvae showed a significantly greater mean preference or acceptance towards hosts than to non-hosts, in both choice and no-choice bioassays, respectively. There were highly significant correlations between the preferences and acceptances of larvae for plants in the choice and no-choice tests. In the no-choice tests, there was a highly significant correlation between the acceptances of neonate larvae towards plants after one and three days (i.e., acceptances changed little over time). Moreover, in these no-choice tests, there was a significant negative correlation between larval acceptance at 1 day and larval mortality after 3 days; that is, the less acceptable a given plant at 1 day, the more likely larvae would fail to establish, feed, and survive on it by three days. Female and larval preferences towards the various plants were also negatively correlated. Together, these data suggest that the selection of a plant for the neonate larva to feed on is largely governed by the preferences of the larva, rather than by the preferences of the female. However, selection of a plant for oviposition by the female, may be important in host selection for reasons unrelated to larval preferences, for example, by encouraging dispersal, perhaps to other plant species, of the neonate larvae and thereby decreasing intersibling competition.
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  • 54
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Plodia interpunctella ; Indian meal moth ; pheromone components ; GC-EAD ; stored-product pest ; behaviour ; flight tunnel ; trapping ; Ephestia kuehniella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pheromone gland extracts from calling female Plodia interpunctella contained at least seven compounds that consistently elicited electroantennographic responses from male antennae upon gas chromatographic analysis. Three of these compounds were found to be the previously identified gland constituents, i.e., (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:OAc), (Z,E)-9,12-tetradecadienal (Z9,E12-14:Ald) and (Z,E)-9,12-tetradecadienol (Z9,E12-14:OH). A fourth EAD-active compound was identified as (Z)-9-tetradecenyl acetate (Z9-14:OAc). The homologue (Z)-11-hexadecenyl acetate (Z11-16:OAc) was also identified in the extracts, but showed no EAD activity. The identity of all five compounds was confirmed by comparison of GC retention times and mass spectra with those of synthetic standards. In flight tunnel tests there were no significant differences in response of male P. interpunctella to the bait containing all four EAD-active compounds and the responses to female gland extacts. A behavioural assay of different two-compound blends in the flight tunnel showed that only addition of the corresponding aldehyde to the major pheromone component Z9,E12-14:OAc raised the male response. A subtractive assay, however, revealed that the exclusion of any of the compounds from the complete four-compound blend reduced its activity significantly. We thus conclude that the female-produced sex pheromone of P. interpunctella consists of at least four components, i.e., Z9,E12-14:OAc, Z9,E12-14:Ald, Z9,E12-14:OH and Z9-14:OAc. In a field trapping test performed in a storage facility, the four-component blend attracted significantly more males of P. interpunctella than traps baited with Z9,E12-14:OAc alone. In contrast, the highest number of Ephestia kuehniella males was found in the traps baited with this major component, suggesting that the secondary pheromone components contribute to the species specificity of the blend.
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  • 55
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    Entomologia experimentalis et applicata 90 (1999), S. 131-140 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; avocadofurans ; Spodoptera exigua ; avocado ; idioblast ; oil cell ; food preference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined the effect of two avocadofurans, 2-(pentadecyl)furan and 2-(heptadecyl)furan, from avocado idioblast oil cells on maturation and larval feeding behavior of a generalist insect herbivore, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Experiments were conducted using two larval sizes: early-stadium larvae refer to those larvae from experiments initiated with neonates while late-stadium larvae refer to those larvae from experiments initiated with third instars. In order to use selected sublethal doses for developmental and behavioral studies on early- and late-stadium larvae, log-dose probit lines were determined using diet incorporation bioassays. Both avocadofurans had similar toxicities to early-stadium larvae [LC50=2.2 and 1.9 μmoles/g of diet for 2-(pentadecyl)furan and 2-(heptadecyl)furan, respectively] and late-stadium larvae (LC50=3.0 and 3.4 μmoles/g of diet, respectively). In diet bioassays extending from egg hatch to adult emergence, the avocadofurans significantly prolonged larval developmental times and reduced S. exigua pupal weights. In 7 d no-choice bioassays initiated with cohorts of newly-molted third instars, the avocadofurans significantly reduced larval weights at various sublethal concentrations (below LC50 values). To test larval feeding deterrence effects of these avocadofurans, choice tests were conducted using early and older instar larvae. A significantly higher proportion of early-stadium larvae preferred control diet over diet treated with either avocadofuran at several sublethal concentrations. Similarly, choice tests with late-stadium larvae showed greater proportions of larvae on control diet than treated diet even at concentrations below the LC50. Moreover, late-stadium larvae consumed significantly more of the control diet than the treated diet. Thus, the avocadofurans may act as feeding deterrents as well as toxicants in plant protection against non-adapted insect herbivores.
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    Entomologia experimentalis et applicata 90 (1999), S. 37-47 
    ISSN: 1570-7458
    Keywords: Choristoneura rosaceana ; obliquebanded leafroller ; Lepidoptera ; Tortricidae ; mating disruption ; mechanisms ; pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An attractive four-component pheromone blend containing a major component Z11-tetradecenyl acetate, and three minor components, E11-tetradecenyl acetate, Z11-tetradecenyl alcohol, and Z11-tetradecenyl aldehyde was tested as a mating disruptant against western Canadian populations of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), in organic apple orchards in British Columbia. Efficacy of this four-component blend was compared to that of partial pheromone blends containing the major component plus one or two minor components. A trapping experiment confirmed that, Conrel® fibre disruption dispensers containing the four-component blend were more attractive than disruption dispensers containing the two- or three-component partial blends. A small-plot protocol was followed to compare atmospheric treatments with these blends as mating disruptants at a release rate of 10 mg ha−1 h−1 and from 1000 dispensers ha−1. Mechanisms of mating disruption, such as false-trail following and camouflage of pheromone plumes, that may be evoked to a greater degree by an attractive blend, did not appear to augment the effectiveness of mechanisms invoked by the less attractive blends, as the proportion of mating among tethered females was equal in plots treated with these blends and was reduced by 85–90% compared to the nontreated control. When the four-component pheromone blend was tested at different release rates, mating disruption in small plots began to break down at a release rate of 1.3 mg ha−1 h−1 using a dispenser density of 1000 ha−1. Above 1.3 mg ha−1 h−1 there was no dose response in release rates tested and at release rates below this dose the proportion of tethered females mating was the same as in the nontreated control. The four-component pheromone blend was tested against, and found to be no more effective than, the two-component partial blend at the threshold release rate of 1.3 mg ha−1 h−1 when it was released from 1000 or 250 disruption dispensers. Our results suggest that disruption mechanisms evoked by the attractive blend did not enhance the mating disruption effect provided by the simple blend, therefore a two-component blend may be useful in an operational mating disruption program for C. rosaceana.
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    Entomologia experimentalis et applicata 92 (1999), S. 321-330 
    ISSN: 1570-7458
    Keywords: rush moth ; Juncus squarrosus ; fluctuating food resources ; ‘bet-hedging’ ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult emergence in Coleophora alticolella held at 15 °C was accelerated by exposure to L18:D6 in autumn and midwinter. The effect decreased during winter and exposure of individuals, held at low temperature over winter, to L18:D6 or L6:D18 at 15 °C at the end of March resulted in the same mean emergence date. Long daylength experienced at 5 °C did not promote emergence nor did exposure to low temperature during winter. The number of adults emerging increased with the length of time cultures were held on short day but was always below 50% of the larvae. When larvae were exposed to L18:D6 and L6:D18 at 15 °C at the end of March, on long day 61% adults emerged and 39% remained in diapause, whereas on short day, 25% became adult and 75% remained diapausing larvae. The possibility of cohort splitting, with some individuals undergoing prolonged diapause, is discussed.
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  • 58
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    Entomologia experimentalis et applicata 93 (1999), S. 179-187 
    ISSN: 1570-7458
    Keywords: artificial diet ; insecticidal activity ; legume pod borer ; Lepidoptera ; Maruca vitrata ; plant lectins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The legume pod-borer Maruca vitrata (Fabricius), [Lepidoptera: Pyralidae] is a major constraint restricting increased cowpea production in tropical Africa and Asia. Since lectins are known to have insecticidal properties against several pests, a survey was undertaken to screen for the effects of 25 lectins from 15 plant families on the development of Maruca pod borer (MPB) larvae. The list included 8 galactose/N-acetylgalactosamine-, 7 mannose-, 5 complex glycan-, 2 sialic acid- and 3, N-acetylglucosamine-specific lectins. Feeding bioassays using artificial diet were carried out at 2% (w/w) topical levels. Although a total of 16 lectins had detrimental effects pertaining either to larval survival, weight, feeding inhibition, pupation, adult emergence and/or fecundity, only the Listera ovata agglutinin (LOA) (Orchidaceae) and Galanthus nivalis (Amaryllidaceae) agglutinin were effective against MPB larvae for all six parameters examined. Larval mortality and feeding inhibition caused by the most active lectin (LOA) was above 60%.
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  • 59
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    Entomologia experimentalis et applicata 91 (1999), S. 287-295 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; oviposition ; host deprivation ; lightbrown apple moth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of mating, age at mating, the presence or absence of a plant leaf, and the deprivation of a suitable ovipositional substrate during when the first ovipositional bout after mating would normally take place, on the lifetime fecundity and fertility (percentage of fertile eggs laid) of female Epiphyas postvittana were investigated. Mating had a significant effect on lifetime fecundity, with mated females laying 2.5 times more eggs than virgin females. Age at mating had a significant effect on both fecundity and fertility, both declining with increasing age when the female was mated. In the presence of a leaf of C. japonica, mated females had a greater lifetime fecundity than when no leaf was present; females in the presence of a C. japonica leaf consistently laid more eggs each day during the first 4–6 days after mating than females without a leaf. When females were deprived of a suitable ovipositional substrate, for the first 22 h after mating, they were significantly less fecund over their lifetime than were control females. Finally, in no-choice tests with three plants of different acceptability to females, the fecundity of females differed in the order C. japonica 〉 Urtica ferox 〉 Tibouchina multiflora. This different fecundity appeared to be inversely related to the pubescence of the leaves, suggesting that leaf texture may be a suitable antixenotic resistance factor for crops to be protected from this insect. These results suggest that strategies whereby mating is delayed or oviposition reduced within a critical period after mating, may result in significant reductions in pest populations.
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  • 60
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    Journal of insect behavior 12 (1999), S. 199-211 
    ISSN: 1572-8889
    Keywords: Lepidoptera ; Tortricidae ; Lobesia botrana ; flight activity ; wind tunnel ; atmospheric pressure ; flight experience ; mating ; age ; olfaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied modulations of flight activity in European grapevine moth females (EGVM) by individual observations in a wind tunnel. The effect of different factors was analyzed: variation in atmospheric pressure prior to the experiments, time of day, first experience of flight, age, mating, and odor of tansy, which attracts females. The circadian flight activity showed a peak the hour preceding the onset of scotophase and sustained activity occurred during the 6 h around this peak. Females with a flight experience in the tunnel took off more quickly than naive ones (3.9 ± 7.4 vs 20.3 ± 22.8 s). Three-day-old unmated females subjected to negative variations of atmospheric pressure (10 hPa) during the 4 h prior to the experiments increased their duration of flight (12.1 ± 8.7 vs 5.3 ± 3.4 s) compared to those not subjected to variation. One-day-old females were less active than older ones; flight was shorter than in 2-day-old females (2.7 ± 6.7 vs 5.1 ± 9.5 s) and fewer of them took off (28 vs 63%). Mating also affected the flight activity of 2-day-old females; mated females flew longer than virgins (12 ± 16.8 vs 5.1 ± 9.5 s) and took off more quickly (6.5 ± 14.4 vs 19.3 ± 20.1 s). Tansy odor in the tunnel did not significantly affect the flight behavior of virgin females, but it increased the proportion of mated females that initiated flight (87 vs 70%) and duration of flight (11.2 ± 24.4 vs 7.2 ± 13.7 s), and it reduced the latency to takeoff (2.1 ± 7.4 vs 8.1 ± 19.1 s). Flight duration in tansy odor was inversely correlated with the total number of eggs laid during the female's whole life. Our experimental settings did not allow observation of movements directed toward the odor source.
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  • 61
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    Journal of comparative physiology 185 (1999), S. 131-141 
    ISSN: 1432-1351
    Keywords: Key wordsHelicoverpa zea ; Noctuidae ; Lepidoptera ; Sex pheromone ; Antagonist
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The limits of a male moth's ability to resolve closely spaced odor filaments have been investigated. Male Helicoverpa zea normally respond to their conspecific sex pheromone blend by exhibiting an upwind flight, which culminates in source contact by at least 50% of the bioassayed individuals. When loaded onto the same filter paper source containing this hitherto attractive pheromone blend, or onto a separate filter paper and co-emitted from the same pipette source with pheromone, (Z)-11-hexadecenyl acetate severely reduced upwind flight and source contact by male H. zea. A similar level of upwind flight inhibition was recorded when the antagonist (Z)-11-hexadecenyl acetate was emitted from its own point source placed 1 mm upwind of the pheromone point source, both plumes being simultaneously emitted in a continuous mode to form a confluent strand. However, (Z)-11-hexadecenyl acetate was less effective in reducing upwind flight and source contact when it was isolated and pulsed from its own source, placed 1 mm either upwind, downwind or cross-wind of a pipette source from which pheromone was simultaneously being pulsed, such that both filaments were separated in time by 0.001–0. 003 s. These results suggest that male H. zea are able to distinguish between odor sources separated by as little as 1 mm in space and 0.001 s in time.
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  • 62
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    Journal of comparative physiology 184 (1999), S. 535-541 
    ISSN: 1432-1351
    Keywords: Key words Insects ; Lepidoptera ; Macroglossum stellatarum ; Colour vision ; Red receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Hymenopterans have long been shown to choose colours by means of the spectral distribution and independently of the intensity (true colour vision). The same ability has only very recently been proven for two butterfly species. We present evidence for the existence of true colour vision in the European hummingbird hawkmoth, Macroglossum stellatarum. Moths were trained in dual-choice situations to spectral lights of a rewarding and an unrewarding wavelength. After training, unrewarded tests were performed during which the intensities of the lights were changed. The results confirm that the species has three spectral receptor types and uses true colour vision when learning the colour of a food source. If colour vision is not possible since only one receptor type is receiving input from both stimuli, the moths learn to associate some achromatic cue correlated to the receptor quantum catch, with the reward. The moths learn spectral cues rapidly and choose correctly after one to several rewarded visits even when trained to different colours in sequence.
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  • 63
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    Journal of insect conservation 3 (1999), S. 15-24 
    ISSN: 1572-9753
    Keywords: census ; conservation ; Lepidoptera ; population monitoring ; survey techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract The use of light traps in sampling moth populations is an established technique used by entomologists and ecologists. However, trap data partly reflect the variable attractiveness of UV light to different species of moth. There are also potential problems of the practicality and expense of running traps in certain locations. An alternative method of recording moth populations is developed, using a modification of the transect count technique used for butterflies (Pollard and Yates, 1993) and recently applied to moths (Spalding, 1997). During transects, moths were observed by torch-light in a 5 by 5 m box, before the recorder walked on for 10 paces, and recorded moths in the next 5 m box. The transect approach was tested in the field, alongside traditional light trap and sugar methods. Transects recorded moth species for relatively little effort, produced repeatable measures of relative density, and provided habitat-specific data. This approach is likely to provide a valuable addition to light trapping in biodiversity inventories, species surveys, and in monitoring the effects of habitat management for conservation.
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  • 64
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    Journal of insect conservation 3 (1999), S. 33-42 
    ISSN: 1572-9753
    Keywords: mapping ; database ; bias recording ; monitoring ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract Data from the Greater Manchester Butterfly Atlas (UK) reveal a highly significant and substantial impact of visits on both species' richness and species' incidence in squares. This effect has been demonstrated for three different zones mapped at different scales. The significant impact of number of visits persists when data are amalgamated for coarser scales. The findings demonstrate that it is essential for distribution mapping projects to record data on recording effort as well as on the target organisms. Suggestions are made as to how distribution mapping may be improved, including a geographically and environmentally representative structure of permanently monitored squares and closer links between distribution mapping and the Butterfly Monitoring Scheme (BMS), which primarily monitors changes in butterfly populations. The benefit to conservation will be data that can be better used to analyse the reasons for changes in ranges and distributions, fundamental for determining priorities and policy decisions.
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  • 65
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    Oecologia 119 (1999), S. 565-571 
    ISSN: 1432-1939
    Keywords: Key wordsVespula ; Lepidoptera ; Phenology ; Shared predator ; Ecological impact
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Introduced social wasps (Vespula vulgaris) reach high densities in some New Zealand beech forests, because honeydew provides an abundant high-energy food source. We manipulated wasp density to estimate an “ecological damage threshold” for large, free-living Lepidoptera larvae. There will be a continuum of ecological damage thresholds for wasp density depending on the prey species or habitat. Experimentally placed small caterpillars had a significantly higher survival rate than large caterpillars, and the survival rate of both groups decreased with increasing wasp density. Spring-occurring caterpillars have a probability of surviving of 0.90–0.95, assuming wasps are the only source of mortality. However, at the peak of the wasp season we predict caterpillars would have virtually no chance (probability of 10−78 to 10−40) of surviving to adults. Wasp abundance must be reduced by at least 88% to conserve the more vulnerable species of free-living caterpillars at wasp densities similar to those observed in our study sites. This equates to a damage threshold of 2.7 wasps per Malaise trap per day. It was exceeded for about 5 months of the year in non-poisoned sites. There are currently no biological or chemical control techniques available in New Zealand that will reduce wasp abundance below this damage threshold throughout the year. Our models show that most Lepidoptera with spring caterpillars will be able to persist, but species with caterpillars occurring in the peak wasp season will be eliminated.
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  • 66
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Lymantriidae ; white-spotted tussock moth ; Orgyia thyellina ; (Z)-6-heneicosen-11-one ; (Z)-6-heneicosen-9-one ; (Z)-6,(E)-8-heneicosadien-11-one ; sex pheromone ; synergism ; quarantine insect ; international trade ; eradication ; Bacillus thuringiensis ; microbial insecticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In 1996, the exotic white-spotted tussock moth (WSTM), Orgyia thyellina (Lepidoptera: Lymantriidae), was discovered in Auckland, New Zealand. Because establishment of WSTM would threaten New Zealand's orchard industry and international trade, eradication of WSTM with microbial insecticide was initiated. To monitor and complement eradication of WSTM by capture of male moths in pheromone-baited traps, pheromone components of female WSTM needed to be identified. Coupled gas chromatographic–electroantennographic detection analysis of pheromone gland extract revealed several compounds that elicited responses from male moth antennae. Mass spectra of the two most EAD-active compounds suggested, and comparative GC-MS of authentic standards confirmed, that they were (Z)-6-heneicosen-11-one (Z6–11-one) and (Z)-6-heneicosen-9-one, the latter termed here “thyellinone.” In field experiments in Japan, Z6–11-one plus thyellinone at a 100:5 ratio attracted WSTM males, whereas either ketone alone failed to attract a single male moth. Addition of further candidate pheromone components did not enhance attractiveness of the binary blend. Through the 1997–1998 summer, 45,000 commercial trap lures baited with 2000 μg of Z6–11-one and 100 μg of thyellinone were deployed in Auckland towards eradication of the residual WSTM population.
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  • 67
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    Behavioral ecology and sociobiology 45 (1999), S. 424-429 
    ISSN: 1432-0762
    Keywords: Key words Mate choice ; Search theory ; Costs and benefits ; Satyrinae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A general and intuitive prediction from models of mate preference is that when the cost of searching for mates increases, individuals should become less choosy. Here, we test this prediction by comparing the mating propensity of females in two populations of the butterfly Pararge aegeria. The populations originated from southern Sweden and Madeira and due to different adult emergence patterns throughout the year, the average density of males per female is likely to be lower on Madeira. Therefore, we expected that the cost of searching should be greater on Madeira and, consequently, that the Madeiran females should be less choosy. In line with predictions, the Madeiran females mated significantly sooner after the first interaction with males than did females from southern Sweden. This difference may reflect a weaker preference for territorial males over non-territorial patrollers in the Madeiran population, because of the greater costs of searching. The Madeiran females also showed a shorter time lag between mating and the start of oviposition. We discuss this unexpected result and propose that the same mechanism could also explain this population difference, i.e. different costs of searching for suitable host plants. Both search processes are fundamental for female reproductive success and we find it plausible that they can be generalised into the same theory of optimal search behaviour.
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  • 68
    ISSN: 1572-9788
    Keywords: lectins ; insect resistance ; transgenic plants ; potato (Solanum tuberosum) ; Lepidoptera ; Homoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of concanavalin A (ConA), a glucose/mannose-specific lectin from jackbean (Canavalia ensiformis), on insect crop pests from two different orders, Lepidoptera and Homoptera, were investigated. When fed to larvae of tomato moth (Lacanobia oleracea) at a range of concentrations (0.02–2.0% of total protein) in artificial diet, ConA decreased survival, with up to 90% mortality observed at the highest dose level, and retarded development, but had only a small effect on larval weight. When fed to peach-potato aphids (Myzus persicae) at a range of concentrations (1–9μM) in liquid artificial diet, ConA reduced aphid size by up to 30%, retarded development to maturity, and reduced fecundity (production of offspring) by 〉35%, but had little effect on survival. With both insects, there was a poor correlation between lectin dose and the quantitative effect. Constitutive expression of ConA in transgenic potatoes driven by the CaMV 35S promoter resulted in the protein accumulating to levels lower than predicted, possibly due to potato not being able to adequately reproduce the post-translational processing of this lectin which occurs in jackbean. However, the expressed lectin was functionally active as a haemagglutinin. Bioassay of L. oleracea larvae on ConA-expressing potato plants showed that the lectin retarded larval development, and decreased larval weights by 〉45%, but had no significant effect on survival. It also decreased consumption of plant tissue by the larvae. In agreement with the diet bioassay results, ConA-expressing potatoes decreased the fecundity of M. persicae by up to 45%. ConA thus has potential as a protective agent against insect pests in transgenic crops.
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  • 69
    ISSN: 1573-5028
    Keywords: Photosystem II ; CP 47 ; random mutagenesis ; XL-1 Red ; mutator strains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intrinsic chlorophyll-protein CP 47 is a component of Photosystem II which functions in both light-harvesting and oxygen evolution. Using the Escherichia coli mutator strain XL-1 Red, we introduced mutations at 14 sites in the large extrinsic loop E of CP 47 and its adjacent transmembrane α-helix VI. Four mutant cell lines were recovered in which the histidyl residues 455H, 466H and 469H were altered. The cell lines H455T, H455Y, H469Y, and the double mutant F432L,H466R exhibited phenotypes that supported the identification of the histidyl residues 455H, 466H and 469H as chlorophyll ligands. Four additional mutant cell lines were recovered which contained mutations at positions 448R in the large extrinsic loop of CP 47. These mutants, R448K, R448Q, R448S, and R448W, exhibited variable phenotypes ranging from moderate alteration of photoautotrophic growth and oxygen evolution rates to a complete inhibition of these parameters. Those mutants exhibiting photoautotrophic growth and oxygen evolution capability under standard conditions were unable to grow photoautotrophically or evolve oxygen when grown at low chloride concentrations. Finally, a mutant cell line exhibiting a substitution at position 342G was recovered. The mutant G342D exhibited moderate alterations of photoautotrophic growth and oxygen evolution. In addition to these alterations, mutants were recovered in which deletions and insertions (leading to frame shifts) and stop codons were introduced. These mutants uniformly lacked the ability to either grow photoautotrophically or evolve oxygen.
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  • 70
    ISSN: 1573-5079
    Keywords: chlorophyll fluorescence ; oxygen evolution ; photoacoustic ; photodamage ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of copper on chlorophyll organization and function during greening of barley was examined, using chlorophyll fluorescence and photoacoustic techniques. Copper was found to inhibit pigment accumulation and to retard chlorophyll integration into the photosystems, as evident from low temperature (77 K) fluorescence spectra. Resolution of the minimal fluorescence (F0) into active and inactive parts, indicated a higher inactive fraction with copper treatment. This was attributed to chlorophyll molecules which failed to integrate normally, a conclusion supported by the longer fluorescence lifetime observed in copper treated plants. A lower ratio of chlorophyll a to b and fluorescence induction transients, showing accelerated Photosystem II closure, both indicate that copper treatment resulted in a larger light-harvesting antenna. Another effect of copper treatment was the suppression of oxygen evolution, indicating a decrease in photosynthetic capacity. We suggest that the non-integrated chlorophyll fraction sensitizes photodamage in the membrane, contributing to disruption of electron flow and pigment accumulation.
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  • 71
    ISSN: 1573-5079
    Keywords: plastoquinone ; cytochrome b-559 ; thylakoid membrane ; Photosystem II ; chlororespiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have found that in isolated spinach thylakoids, plastoquinone-pool (PQ-pool), after its photoreduction, undergoes dark-reoxidation with the half-time of τ1/2 = 43 ± 3 s. To explain the observed rates of PQ-pool reoxidation, a nonenzymatic plastoquinol (PQH2) autoxidation under molecular oxygen and an enzymatic oxidation by the low-potential form of cytochrome b-559 (cyt. b-559LP), as the postulated PQ-oxidase in chlororespiration, were investigated. It was found that the autoxidation rate of PQH2 in organic solvents and liposomes was too low to account for the observed oxidation rate of PQH2 in thylakoids. The rate of cyt. b-559LP autoxidation in isolated Photosystem II was found to be similar (τ1/2 = 26 ± 5 s) to that of the PQ-pool. This suggests that the LP form of cyt. b-559 is probably responsible for the PQ-oxidase activity observed during chlororespiration.
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  • 72
    ISSN: 1573-5079
    Keywords: anaerobiosis ; chlorophyll fluorescence ; chlororespiration ; fluorescence induction ; Photosystem II ; Pisum sativum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analysed the changes of the chlorophyll (Chl) a fluorescence rise kinetic (from 50 μs to 1 s) that occur when leaves or chloroplasts of pea ( Pisum sativum L.) are incubated under anaerobic conditions in the dark. In control leaves, Chl a fluorescence followed a typical O-J-I-P polyphasic rise [Strasser et al. (1995) Photochem Photobiol 61: 32–42]. Anaerobiosis modified the shape of the transient with the main effect being a time-dependent increase in the fluorescence yield at the J-step (2 ms). Upon prolongation of the anaerobic treatment (〉 60 min), the O-J-I-P fluorescence rise was eventually transformed to an O-J (J = P) rise. A similar transformation was observed when pea leaves were treated with DCMU or sodium dithionite. Anaerobiosis resulted in a 10–20% reduction in the maximum quantum yield of the primary photochemistry of Photosystem II, as measured by the ratio of the maximal values of variable and total fluorescence (FV/FM). When the leaves were returned to the air in the dark, the shape of the fluorescence transient showed a time-dependent recovery from the anaerobiosis-induced change. The original O-J-I-P shape could also be restored by illuminating the anaerobically treated samples with far-red light but not with blue or white light. Osmotically broken chloroplasts displayed under anaerobic conditions fluorescence transients similar to those observed in anaerobically treated leaves, but only when they were incubated in a medium comprising reduced pyridine nucleotides (NADPH or NADH). As in intact leaves, illumination of the anaerobically treated chloroplasts by far-red light restored the original O-J-I-P transient, although only in the presence of methyl viologen. The results provide additional evidence for the existence of a chlororespiratory pathway in higher plant cells. Furthermore, they suggest that the J-level of the fluorescence transient is strongly determined by the redox state of the electron carriers at the PS II acceptor side.
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  • 73
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    Journal of chemical ecology 25 (1999), S. 2305-2312 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Lymantriidae ; Lymantria fumida ; Lymantria monacha ; nun moth ; sex pheromone ; periodicity ; calling behavior ; reproductive isolation ; disparlure ; (7R,8S)-cis-7,8-epoxy-2-methyloctadecane ; (7S,8R)-cis-7,8-epoxy-2-methyloctadecane ; 2-methyl-Z7-octadecene ; (7R,8S)-cis-7,8-epoxy-octadecane ; (+)-monachalure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Extracts of pheromone glands from female Lymantria fumida were analyzed by coupled gas chromatographic–electroantennographic detection (GC-EAD) and by coupled GC–mass spectrometry (MS). The two compounds that elicited responses from male L. fumida antennae were identified as cis-7,8-epoxy-2-methyloctadecane (disparlure) and 2-methyl-Z7-octadecene (2me-Z7–18Hy). Field experiments in northern Japan demonstrated that synthetic (7R,8S)-cis-7,8-epoxy-2-methyloctadecane [(+)-disparlure] and 2me-Z7–18Hy are synergistic sex pheromone components of L. fumida. (7S,8R)-cis-7,8-Epoxy-2-methyloctadecane [(−)-disparlure] had no behavioral effect on male L. fumida. Traps baited with (+)-disparlure and 2me-Z7–18Hy captured male L. fumida between 21:00 and 24:00 hr, whereas traps baited with (+)-monachalure [(7R,8S)-cis-7,8-epoxy-octadecane], (+)-disparlure and 2me-Z7–18Hy attracted males of the nun moth, L. monacha L., between 02:00 and 04:00 hr. Both temporal separation of pheromonal communication and specificity of pheromone blends seem to contribute to the reproductive isolation of sympatric and coseasonal L. fumida and L. monacha.
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  • 74
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    Journal of chemical ecology 25 (1999), S. 2547-2559 
    ISSN: 1573-1561
    Keywords: Yponomeuta cagnagellus ; ermine moth ; Lepidoptera ; speciation ; specialization ; plant surface compounds ; oviposition ; host discrimination ; Euonymus europaeus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Yponomeuta cagnagellus is a phytophagous moth species specialized on Euonymus europaeus. Host discrimination by the adult female is an important aspect of host specialization and is based mainly on the distinctive secondary chemistry of host and nonhosts. This paper describes a bioassay that was developed to study the effect of isolated plant surface compounds on Yponomeuta oviposition. Adult moths recognize their hosts through chemical stimuli on the leaf or twig surface. Relatively apolar compounds extracted from the host twig surface by washing in dichlormethane do not stimulate oviposition. More polar, methanol-soluble compounds do, and this stimulation is dose dependent. Moths are able to recognize hosts solely by their surface compounds: females show a strong preference for artificial twigs treated with methanolic extracts of their hosts compared to those treated with methanolic extracts of nonhosts Crataegus monogyna and Prunus spinosa (both of which are hosts for closely related Y. padellus). Shape and surface characteristics of the oviposition substrate also influence oviposition. The substrate needs to resemble the basic form of a twig (i.e., cylindrical), and females prefer a coarse surface with irregularities over a smooth one.
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  • 75
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    Journal of chemical ecology 25 (1999), S. 1233-1245 
    ISSN: 1573-1561
    Keywords: Swallowtail butterfly ; Papilionidae ; Papilio troilus ; Lepidoptera ; Lauraceae ; Sassafras albidum ; oviposition stimulant ; 3-trans-caffeoyl-muco-quinic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Female butterflies of the spicebush swallowtail, Papilio troilus, are specialists, ovipositing on plants in the family Lauraceae. Column chromatography and HPLC were used to isolate an oviposition stimulant from the leaves of one of its hosts, Sassafras albidum. The stimulant was identified as 3-trans-caffeoyl-muco-quinic acid on the basis of FAB-MS and 1H NMR spectra as compared to a compound previously isolated from another plant. It was not active alone, but it increased the oviposition activity of butterflies when combined with other stimulant(s) at a concentration of 7 ng/mm2 leaf surface area. Other caffeoylquinic acid isomers tested did not have this effect. This is the first report of a swallowtail contact oviposition stimulant from a plant in the family Lauraceae.
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  • 76
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    Journal of chemical ecology 25 (1999), S. 1343-1351 
    ISSN: 1573-1561
    Keywords: Host-plant volatiles ; apple ; Malus domestica ; reproductive behavior ; codling moth ; Cydia pomonella ; Tortricidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Apple volatiles stimulated pheromone release, oviposition, and upwind orientation in female codling moths, Cydia pomonella. Green apples increased the percentage of virgin females calling, the duration of female calling, and advanced the onset of egg-laying in gravid females. In a tube olfactometer, both virgin and mated females were more active in the presence of apple volatiles than in clean air. They responded by walking while wing-fanning; mated females showed a stronger attraction response than unmated females.
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  • 77
    ISSN: 1573-1561
    Keywords: Tritrophic interactions ; Lima bean ; Phytoseiulus persimilis ; Tetranychus urticae ; Spodoptera exigua ; Acari ; Lepidoptera ; infochemicals ; herbivore-induced plant volatiles ; nonprey herbivores ; feces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The effect of volatiles related to feeding activity of nonprey caterpillars, Spodoptera exigua, on the olfactory response of the predatory mites Phytoseiulus persimilis was examined in a Y-tube olfactometer. At a low caterpillar density (20 caterpillars on 10 Lima bean leaves), the predators were significantly more attracted to volatiles from infested leaves on which the caterpillars and their products were present or from infested leaves from which the caterpillars and their products had been removed when compared to volatiles from uninfested leaves. The predators, however, significantly avoided odors from 20 caterpillars and their products (mainly feces) removed from bean leaves. In contrast, at a higher caterpillar density (100 caterpillars on 10 Lima bean leaves), the predators avoided volatiles from caterpillar-infested bean leaves. Volatiles from infested leaves from which the caterpillars and their products had been removed were not preferred over volatiles from uninfested leaves. Volatiles from feces collected from 100 caterpillars were strongly avoided by the predators, while the behavior of the predatory mites was not affected by volatiles from 100 caterpillars removed from a plant. The data show that carnivorous arthropods may avoid nonprofitable herbivores. This avoidance seems to result from an interference of volatiles from herbivore products with the attraction to herbivore-induced plant volatiles.
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  • 78
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    Journal of chemical ecology 25 (1999), S. 1945-1960 
    ISSN: 1573-1561
    Keywords: Insect–plant interaction ; midgut alkalinization ; phylogenetic distribution ; Mecopterida ; Diptera ; Lepidoptera ; Trichoptera ; polyphenolics ; alkylating agents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The phylogenetic distribution of reported midgut pH values among larval Mecopterida supports a model in which the common ancestor of this group possessed an alkaline midgut, with subsequent loss of this trait in the lineage leading to the muscomorphan Diptera. The relationship between midgut pH and diet guild rank within the Lepidoptera and Diptera was tested by assigning numerical values to diet guilds (i.e., fruit, grasses, herbs, trees and shrubs, and organic detritus). Lepidopteran superfamilies were found to differ significantly in both midgut pH and in diet guild rank. Regression of mean superfamily midgut pH against mean superfamily diet guild rank yielded an R 2 of 0.79 (N = 10), whereas regression of species midgut pH against species diet guild rank yielded an R 2 of only 0.15 (N = 60). Species feeding on foliage of plant taxa high in tannins and on Solanaceae have midgut pH values above 9, and midgut pH in species feeding on these taxa is positively related to diet guild. In contrast, species feeding on the foliage of plant taxa containing terpenes, DIMBOA, glucosinolates, and pyrrolizidine alkaloids have midgut pH values near 8, and midgut pH of these species is either not related to diet guild (all species) or is negatively related to diet guild rank when the analysis is limited to the Noctuoidea. The data suggest that decreased midgut pH in species feeding on plants containing terpenes, DIMBOA, glucosinolates, and pyrrolizidine alkaloids may be an adaptive response that overrides selection for high pH in the presence of tannins and that midgut pH may be one factor contributing to the limitation of the host plant range of many species of lepidopteran herbivores.
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  • 79
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    Journal of chemical ecology 25 (1999), S. 2535-2545 
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Lymantriidae ; Lymantria xylina ; Lymantria dispar ; Lymantria monacha ; Lymantria fumida ; sex pheromone ; reproductive isolation ; (7R,8S)-cis-7,8-epoxy-2-methyleicosane ; (7S,8R)-cis-7,8-epoxy-2-methyleicosane ; 2-methyl-Z7-eicosene ; (7R,8S)-cis-7,8-epoxy-2-methylnonadecane ; (7S,8R)-cis-7,8-epoxy-2-methylnonadecane ; (7R,8S)-cis-7,8-epoxy-3-methylnonadecane ; (7S,8R)-cis-7,8-epoxy-3-methylnonadecane ; disparlure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract cis-7,8-Epoxy-2-methyleicosane is a sex pheromone component of the Casuarina moth, Lymantria xylina Swinhoe. The compound was extracted from pheromone glands of female moths and was identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) and GC–mass spectrometry. In field experiments in Taiwan, traps baited with either or both of (7R,8S)-cis-7,8-epoxy-2-methyleicosane (〉99% ee) [termed here (+)-xylinalure] and (7S,8R)-cis-7,8-epoxy-2-methyleicosane (〉99% ee) [termed here (−)-xylinalure] captured male L. xylina. Addition of further candidate pheromone components to xylinalure did not enhance its attractiveness. Demonstration of whether or not female L. xylina produce both optical isomers of xylinalure, and determination of the ratio, will require pheromone extract analyses on a chiral, enantiomer-separating column (as yet unavailable) or derivatization of epoxides in accumulated gland extracts. Attraction of male L. xylina to either enantiomer of xylinalure contrasts with enantiospecific production of, and/or response to, epoxy pheromones in congeners. With no other nocturnal lymantriid moth known in Taiwan to utilize xylinalure for pheromonal communication, enantiospecific “fine tuning” of xylinalure, or evolution of a more complex pheromone blend, may not have been necessary for L. xylina to maintain specificity of sexual communication. Racemic xylinalure will be appropriate for pheromone-based detection surveys of L. xylina in North America.
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  • 80
    ISSN: 1573-1561
    Keywords: Coniesta ignefusalis ; Acigona ignefusalis ; Lepidoptera ; Pyralidae ; sex pheromone ; (Z)-7-dodecen-1-ol ; (Z)-5-decen-1-ol ; (Z)-7-dodecenal ; (Z)-7-dodecenyl acetate ; (Z)-9-tetradecen-1-ol
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Five active compounds were detected during analyses of ovipositor washings and effluvia from virgin female Coniesta ignefusalis moths by gas chromatography (GC) linked to electroantennographic (EAG) recording from a male moth. These were identified as (Z)-7-dodecen-1-ol (Z7–12:OH), (Z)-5-decen-1-ol (Z5–10:OH), (Z)-7-dodecenal (Z7–12:Ald), (Z)-7-dodecenyl acetate (Z7–12:Ac), and (Z)-9-tetradecen-1-ol (Z9–14:OH) by comparison of their GC retention times, mass spectra, and EAG activities with those of synthetic standards. Laboratory tests of dispensers for these compounds showed that release rates from polyethylene vials increased to relatively uniform values after three to four days, but release from septa was very rapid and nonuniform and decreased to low levels after two to three days. Trapping tests in Niger showed that the major component, Z7–12:OH, and two of the minor components, Z5–10:OH and Z7–12:Ald, were essential for attraction of male C. ignefusalis moths. The most attractive blend contained these three components in a 100:5:3.3 ratio in a polyethylene vial, which emitted the components in similar proportions to those produced by the female C. ignefusalis moth. Water traps baited with this blend containing 1 mg of Z7–12:OH caught more male C. ignefusalis moths than traps baited with newly emerged female moths. Addition of up to 10% of the corresponding E isomers of the pheromone components had no effect on catches, but addition of the other two minor components detected, Z7–12:Ac and/or Z9–14:OH, to the attractive blend at naturally occurring levels caused significant reductions in trap catch.
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  • 81
    ISSN: 1573-1561
    Keywords: Lepidoptera ; Tortricidae ; Lobesia botrana ; grapevine moth ; wind tunnel ; behavior ; flight track recording ; (E)-7,(Z)-9-dodecadienyl acetate ; (E)-7,(Z)-9-dodecadien-1-ol ; (Z)-9-dodecenyl acetate ; (E)-9-docecenyl acetate ; 11-dodecenyl acetate ; pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The behavioral responses of Lobesia botrana males to calling females, pheromone gland extracts, and synthetic sex pheromones were recorded in a wind tunnel. Gland extracts and synthetic pheromones were released from a pheromone evaporator. The numbers of males reaching the source and their flight tracks in response to calling females and pheromone gland extracts were compared to those of synthetic blends. Upwind flights to natural sex pheromone were straighter and faster than to a three-component blend of (E)-7,(Z)-9-dodecadienyl acetate (E7,Z9–12:Ac), (E)-7,(Z)-9-dodecadien-1-ol (E7,Z9–12:OH), and (Z)-9-docecenyl acetate (Z9–12:Ac) (100:20:5). The optimum ratio of E7,Z9–12:OH and Z9–12:Ac to E7,Z9–12:Ac was found to be 5% and 1%, respectively. An additional seven compounds identified in the sex pheromone gland were investigated for their biological activity. Two unsaturated acetates, i.e., (E)-9-dodecenyl acetate (E9–12:Ac) and Δ11-dodecenyl acetate (Δ11–12:Ac), increased the number of males reaching the source as well as straightness, linear velocity, and decreased the track angle of upwind flight. Optimum response was obtained by releasing 10 pg/min E7,Z9–12:Ac in a mixture with 0.5 pg/min E7,Z9–12:OH, 0.1 pg/min Z9–12:Ac, 0.1 pg/min E9– 12:Ac and 1 pg/min Δ11-12–Ac. The saturated acetates previously identified in the female glands were biologically inactive.
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  • 82
    ISSN: 1573-5079
    Keywords: antenna system ; chlorophyll–proteins ; HPLC ; LHC II ; Photosystem II ; spinach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The protein components of the Photosystem II antenna system, isolated from spinach thylakoids, have been resolved by reversed-phase high performance liquid chromatography (RP-HPLC) using a butyl-silica stationary phase packed either into analytical or semi-preparative columns. Peak identification has been accomplished by a combination of various SDS–PAGE systems employing either Comassie (or silver) staining or immunological detection using polyclonal antibodies raised against LHC II and against CP29, CP26 and CP24 proteins and by aminoacid microsequence. Moreover, peak identification is consistent with the molecular masses determined by Electrospray Ionization Mass Spectrometry (HPLC-ESI-MS). The developed RP-HPLC method allows the resolution of all the protein components of the Photosystem II major Light Harvesting Complex (LHC II) and minor PS II antenna complex (CP24, CP26 and CP29) from grana membranes (BBY) and estimation of their relative stoichiometry in natural and stressed conditions, avoiding the expensive and time consuming separation procedure by sucrose-gradient ultracentrifugation and isoelectrofocusing.
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  • 83
    ISSN: 1573-5079
    Keywords: cyclic electron transport ; fluorescence ; metal ions ; Photosystem II ; thermal dissipation
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    Topics: Biology
    Notes: Abstract Simultaneous fluorescence and photoacoustic measurements have been used to study the effects of metal ions (copper, lead, and mercury) during dark incubation of thylakoid membranes. The values of the chlorophyll fluorescence parameters Fo (initial fluorescence yield with the reaction centers in the open state), Fm (maximal fluorescence yield), Ft (steady state fluorescence yield) and the calculated parameters, Φo (maximal quantum yield of Photosystem II photochemistry) and Φt (actual quantum yield of Photosystem II photochemistry), strongly decreased in the presence of the metal ions coinciding with an increase in the non-photochemical deexcitation rate constant k(N). It was observed that photosynthetic energy storage measured by photoacoustic spectroscopy also decreased but a large portion of energy storage remained unaffected even at the highest metal ion concentrations used. A maximal inhibition of photosyntheti c energy storage of 80% and 50% was obtained with Hg2+ and Cu2+-treated thylakoids, respectively, while energy storage was insensitive to Pb2+. The results are consistent with the known predominant inhibition of the donor side of Photosystem II by the metal ions. The insensitive portion of energy storage is attributed to the possible recurrence of cyclic electron transport around Photosystem II that would depend on the extent of inhibition produced on the acceptor side by the metal ion used.
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  • 84
    ISSN: 1573-5079
    Keywords: manganese-stabilizing protein ; oxygen evolution ; Photosystem II ; protein structure prediction ; PsbO protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Modern computational methods for protein structure prediction have been used to study the structure of the 33 kDa extrinsic membrane protein, associated to the oxygen evolving complex of photosynthetic organisms. A multiple alignment of 14 sequences of this protein from cyanobacteria, algae and plants is presented. The alignment allows the identification of fully conserved residues and the recognition of one deletion and one insertion present in the plant sequences but not in cyanobacteria. A tree of similarity, deduced from pair-wise comparison and cluster analysis of the sequences, is also presented. The alignment and the consensus sequence derived are used for prediction the secondary structure of the protein. This prediction indicates that it is a mainly-beta protein (25–38% of β-strands) with no more than 4% of α-helix. Fold recognition by threading is applied to obtain a topological 2D model of the protein. In this model the secondary structure elements are located, including several highly conserved loops. Some of these conserved loops are suggested to be important for the binding of the 33 kDa protein to Photosystem II and for the stability of the manganese cluster. These structural predictions are in good agreement with experimental data reported by several authors.
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  • 85
    ISSN: 1573-5079
    Keywords: chilling ; Photosystem II ; quantum efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chl fluorescence of mature leaves in low-temperature treated plants was studied under identical measuring conditions in a segregating population of the F3 offspring of a cross between a chilling-tolerant and a chilling-sensitive tomato species. Through recombination of genes involved in photosynthesis, the population revealed a wide, continuous variability of photosynthetic capacity from plants performing much worse to those performing better than the parental lines of the cross. In the parental species, a nearly linear correlation was observed between photochemical chl fluorescence quenching (qP) and O2 evolution over a wide temperature range. Across the F3 generation, still a weak correlation between the two parameters was found at 20 °C, but not at 10 °C, when measured under identical conditions. This indicates that the fraction of open reaction centres could at least in part be adjusted to the photosynthetic capacity of the individual genotype. However, the correlation was so weak, that the previously suggested use of qP as a selection criterion for chilling tolerance of photosynthesis in breeding programs is regarded as doubtful, as long as photosynthesis rates are not measured in addition. Quantum efficiency of Photosystem II (ΦPSII) was strongly dependent on qP both at 20 and at 10 °C measuring temperature and depended on the quantum efficiency of open reaction centres (F′v/F′m) at 20, but not at 10 °C. F′v/F′m, in turn, correlated negatively with the processes of energy dissipation by the mechanisms of non-photochemical quenching (qN), i.e. its fast-relaxing component (qF) and photoinhibitory quenching (qI).
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  • 86
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    Evolutionary ecology 13 (1999), S. 709-719 
    ISSN: 1573-8477
    Keywords: Anthocharis cardamines ; aposematism ; Lepidoptera ; palatability ; Pieridae ; Pieris brassicae ; P. napi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It has been suggested that the white coloration of Pieridae butterflies is a warning signal and therefore all white Pieridae could profit from a mimetic resemblance. We tested whether green-veined white (Pieris napi) and orange-tip (Anthocharis cardamines) butterflies benefit from white coloration. We compared their relative acceptability to wild, adult pied flycatchers (Ficedula hypoleuca) by offering live A. cardamines and P. napi together with two non-aposematic butterflies on the tray attached to birds' nesting boxes. Experienced predators equally attacked white and non-white butterflies, and the order of attack among the Pieridae was random. If anything, there was a slight indication that the female A. cardamines was the least favoured prey. Since birds did not avoid white coloration, we compared the palatability of these two species against known palatable and unpalatable butterflies by presenting them to great tits (Parus major). Pieris brassicae, which has been earlier described as unpalatable, was also included in the palatability test. However, there were no significant differences in the palatability of the butterflies to birds, and even P. brassicae was apparently palatable to the great tits. Our results do not unambiguously support the hypothesis that the white coloration of Pieridae would signal unpalatability. Nevertheless, in our last experiment, pied flycatchers often rejected or left untouched free flying P. napi and A. cardamines. This suggests that other features in a more natural situation, such as the agile flight pattern or odours might still make them unprofitable to birds.
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  • 87
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    Entomologia experimentalis et applicata 86 (1998), S. 89-96 
    ISSN: 1570-7458
    Keywords: spruce budworm ; amino acids ; chemosensilla ; electrophysiology ; gustation ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An electrophysiological approach was used to record the responses of maxillary styloconic sensilla of fourth- and sixth-instar larvae of the spruce budworm Choristoneura fumiferana to 14 amino acids. One cell in the lateral styloconic sensillum was identified as an amino acid-sensitive neuron. All of the amino acids tested, except l-proline and l-arginine, were detected by this cell. Arginine did not evoke a response from either the medial or lateral styloconic sensilla. Proline evoked responses from a cell in the medial styloconic sensillum. It is known from previous behavioural work that l-proline is a phagostimulant and l-valine inhibits feeding in Choristoneura; we thus further characterized the responses to these two amino acids. For both instars, l-proline was detected as low as 0.001 mmol/l and the maximal response was at 50 mmol/l. Stimulation of fourth- and sixth-instar larvae with l-valine showed that the maximum firing frequency was obtained at 1 mmol/l. Above and below this concentration, firing frequency decreases. Sensory responses to the amino acids stimuli did not correlate with known behavioral responses to similar stimuli.
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  • 88
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    Entomologia experimentalis et applicata 86 (1998), S. 331-336 
    ISSN: 1570-7458
    Keywords: adult diet ; fecundity ; larval phase ; Lepidoptera ; Noctuidae ; Spodoptera exempta
    Source: Springer Online Journal Archives 1860-2000
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  • 89
    ISSN: 1570-7458
    Keywords: attraction ; Allium ; EAG ; generations ; green leaf volatiles ; Hyponomeutoidea ; Lepidoptera ; leek moth ; walking behaviour ; olfactory responsiveness ; rearing conditions ; sensitivity variations ; sulphur volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three strains of the leek moth, Acrolepiopsis assectella, were compared: two reared on leek leaves (Allium porrum) for which generations 10 to 12 (L) or generation 2 (G2) were used, the third one (D) reared on an artificial diet incorporating leek powder, for which generation ca 140 was examined. The walking behaviour (L and D) and the antennal responsiveness (L, G2 and D) were compared between individuals subjected to leek leaf odour and 4 volatiles identified in these leaves: 2 specific sulphur ones (dipropyl thiosulphinate and dipropyl disulphide) and 2 ‘general green leaf volatiles’ (cis-3-hexen-1-ol and trans-2-hexen-1-ol). The walking behavioural thresholds to leek odour, dipropyl thiosulphinate, and cis-3-hexen-1-ol were lower for L than for D females. The chemoanemotactic responses to dipropyl disulphide are almost identical, and trans-2-hexen-1-ol has nearly no activity. Accordingly, the olfactory sensitivity (assessed by EAG) to sulphur volatiles and cis-3-hexen-1-ol was higher for L and G2 females than for D ones. The threshold for thiosulphinate was at a concentration (v/v) of 4 × 10-4 M/l for D females, 4 × 10-5 M/l for L females and 4 × 10-8 M/l for G2 ones. It may be hypothesised that laboratory rearing conditions cause variations in the thresholds of antennal sensitivity and walking behaviour to specific and more efficient leek volatiles. This may result from the selective pressures experienced by the larvae reared in the laboratory.
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  • 90
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    Entomologia experimentalis et applicata 86 (1998), S. 313-318 
    ISSN: 1570-7458
    Keywords: Ostrinia palustralis ; sex pheromone ; identification ; (E)-11-tetradecenyl acetate ; (Z)-11-tetradecenyl acetate ; Lepidoptera ; Pyralidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By means of gas chromatography with electroantennographic detection, gas chromatography-mass spectrometry and a series of bioassays, (E)-11-tetradecenyl acetate (E11-14:OAc) and (Z)-11-tetradecenyl acetate (Z11-14:OAc) at a ratio of 99:1 were identified as female sex pheromone components of Ostrinia palustralis. The average amounts of E11- 14:OAc and Z11-14:OAc in a single sex pheromone gland were 37.2±24.4 ng and 0.3±0.2 ng, respectively. In a wind-tunnel bioassay, the binary blend of E11- and Z11-14:OAc elicited the same male behavioral responses as did virgin females.
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  • 91
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    Entomologia experimentalis et applicata 88 (1998), S. 1-7 
    ISSN: 1570-7458
    Keywords: Lobesia botrana ; Lepidoptera ; Tortricidae ; fungus ; Botrytis cinerea ; attraction ; olfaction ; gustation ; olfactometer ; larval behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vineyards, larvae of Lobesia botrana (Denis and Schiffermüller) (Lepidoptera: Tortricidae) and Botrytis cinerea (Persoon: Fries) often occur together. This study was carried out to establish whether first instar larvae are attracted by the fungus. Olfactory and gustatory responses of larvae to the fungus were investigated on grape berry clusters (Vitis vinifera) and in two types of olfactometer. In clusters infected partly by B. cinerea, 82% of first instar larvae settled where berries had been infected. In the olfactometers, first instar larvae detected and discriminated between two tested foods. They significantly preferred synthetic media or grape berries (cv., 'Alphonse Lavallée' or 'Cabernet Sauvignon') infected with B. cinerea to non-infected controls. The olfactory response led to 62.2% to 72.6% of the first instar larvae attracted by the fungus and the association of olfactory with gustatory responses resulted in similar rates (64.1% to 81.6%). So, the larvae were most attracted by synthetic media or grape berries infected by the fungus as compared to the controls. Olfaction appears to be the main sense involved in this attraction process.
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  • 92
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Gelechiidae ; Pectinophora gossypiella ; cotton ; pheromone ; wind tunnel ; attraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mechanisms by which the application of formulated pheromone interferes with mating in the pink bollworm moth (PBW), Pectinophora gossypiella were examined in 0.4 ha cotton fields using high-dose (78 mg A.I.) sealed polyethylene dispensers. Walk-in, field wind tunnels 6.2 m long were placed over two rows of cotton. Treatments consisted of a control, a tunnel in a field free of disruptant formulation; a 3-rope treatment, in which the field was free of pheromone but one of the cotton rows in the wind tunnel was treated with 3 PBW ropes; and a rope-grid treatment, in which the field was treated with PBW ropes at the standard density of 1000 ha−1 and one of the cotton rows inside the wind tunnel was treated with 3 PBW ropes. We released marked males into the tunnels near sunset or held them in field cages for 24 h prior to assay. Two pheromone traps at the tunnel's upwind end monitored the ability of males to locate point sources of pheromone. In the 3-rope tunnel, traps placed upwind of the cotton row treated with disruptant pheromone captured far fewer males than those placed upwind of the untreated cotton row. In the tunnel situated in the centre of the rope-gridded field, very few males were caught in traps in both rows, indicating a camouflage of the pheromone plumes from the traps by the background of airborne disruptant drawn into the tunnel from the field. Activity of moths near the synthetic pheromone sources was video-recorded. Males oriented to, landed on or near, and walked on or near, PBW ropes, indicating competition between pheromone sources as a mechanism of mating disruption. Most males visiting PBW ropes became quiescent or disappeared from the field of view after a few minutes, suggesting a habituation/adaptation of response. The rhythm of attraction of males held in the field for 24 h before release was comprised of a small peak of activity near 2000 h, with the majority of attraction between 2300 and 0300 h. Much of the attraction before 0100 appears to be an advancement of the male's normal diel rhythm, caused by the presence of disruptant. Together these findings indicate that mating disruption of pink bollworm using the PBW ropes is achieved by a combination of mechanisms: a camouflage of natural plumes, competition between pheromone sources, habituation, and some advancement of the male's rhythm of response.
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  • 93
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    Entomologia experimentalis et applicata 87 (1998), S. 209-209 
    ISSN: 1570-7458
    Keywords: Chrysodeixis chalcites ; EAG ; electroantennography ; electrophysiology ; greenhouse cultures ; Lepidoptera ; mating disruption ; Noctuidae ; paprika ; pheromone distribution ; sex pheromones ; sweet pepper
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mating disruption using pheromone dispensers is an emerging insect control method in greenhouses in the Netherlands. For routine measurements of the pheromone level in greenhouses a portable and compact device based on electroantennography (EAG) was developed. The instrument was tested in different greenhouses under varying conditions using antennae of males of the noctuid moth Chrysodeixis chalcites. Relative differences in pheromone concentration between greenhouses loaded with pheromone dispensers and control greenhouses could be measured in a reliable way. Changes in pheromone concentration were clearly demonstrated by measurements during the growing season. The advantages of the instrument presented over previously described devices are its true portableness, ease of use and uncomplicated measuring principle. The device can be operated routinely by non-experts, and many measurements can be made in a short period of time. Preliminary outdoor measurements using antennae of male Cydia pomonella as sensor showed the potential of the instrument for use in the open field. The portable EAG sensor described here may provide a practical means for monitoring pheromone concentration and dispersal from dispensers applied for mating disruption.
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  • 94
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    Entomologia experimentalis et applicata 88 (1998), S. 101-107 
    ISSN: 1570-7458
    Keywords: sex pheromone ; pheromone-based mating disruption ; Spilonota ocellana ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The potential for pheromone-based mating disruption of eye-spotted bud moth (ESBM), Spilonota ocellana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), in apple orchards in the Okanagan Valley of British Columbia was examined in small-plot trials. In a preliminary experiment, treatment of the orchard atmosphere with a 99:1 blend of Z8-tetradecenyl acetate (Z8-14:OAc) and Z8-tetradecenyl alcohol (Z8-14:OH) completely inhibited captures of male ESBM in pheromone-baited traps, but treatment with Z8-14:OAc alone did not. Therefore, all subsequent trials used the two-component blend as a disruptant. Mean catches of male ESBM in traps baited with 0.1, 1, 10, or 20 mg of 99:1 Z8-14:OAc and Z8-14:OH were significantly reduced (81–97%) in pheromone-treated plots relative to similar traps placed in control plots. In both control and treated plots, there was a significant positive relationship between trap bait dose and trap catch. In pheromone-treated plots, this suggests that high doses of trap baits over-ride the camouflage effect of disruption or overcome the effect of sensory adaptation and habituation. The number of virgin-female baited traps capturing at least one male ESBM was reduced by 96%, and mating of virgin females on mating tables was reduced by 95% in plots treated with the two-component pheromone. The total amount of Z8-14:OAc released from pheromone disruption dispensers during the latter field trials was estimated to average 6.4 g ha-1 over 11 days or 26.4 mg ha-1 h-1. The low levels of Z8-14:OH released from disruption dispensers could not be estimated by GC analysis. Dispensers loaded with a 99:1 blend of Z8-14:OAc and Z8-14:OH were highly attractive to males in baited traps, indicating that they have the potential to induce false trail following.
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  • 95
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    Journal of insect behavior 11 (1998), S. 507-538 
    ISSN: 1572-8889
    Keywords: monarch butterflies ; Danaus plexippus ; Danainae ; Lepidoptera ; Nymphalidae ; oviposition behavior ; Asclepias ; Asclepiadaceae ; chemoreceptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The monarch butterfly, Danaus plexippus L., oviposits mainly on plants in the Asclepiadaceae, particularly within the genus Asclepias. We studied postalightment oviposition behavior of monarch females on three host species—Asclepias curassavica, A. incarnata , and A. tuberosa. After landing on the host, they used their forelegs, midlegs, and antennae to assess plant suitability. When these appendages were examined by scanning electron microscopy, contact chemoreceptor sensilla were found. In choice tests, A. incarnata was most preferred, while A. tuberosa was least preferred. However, the use of appendages varied for the different host species. Antennae were most frequently used during post-alightment behavior on A. curassavica, whereas forelegs were used more often on A. incarnata, and all three appendages were used extensively on A. tuberosa. Use of the midlegs was generally followed by use of the antennae. Tasting with either forelegs or antennae apparently may lead to egg laying on some host species. Rupture of the plant surface by midleg spines was also observed. The behavior and host preference of individual females varied significantly and may reflect differences in receptor sensitivity.
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  • 96
    ISSN: 1572-8889
    Keywords: trail following ; 5β-cholestane-3-one ; pheromone ; cooperative foraging ; social caterpillar ; bolsa ; silk ; Pieridae ; Eucheira ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The larva of the Madrone butterfly Eucheira socialis (Lepidoptera: Pieridae) secretes a trail pheromone from the ventral surface of the posterior tip of its abdomen. Caterpillars mark trails by bringing the secretory site into brief contact with the substrate during a locomotive cycle. Foragers mark most heavily when they move onto new branches and little, if at all, when they move over established trails or when they return to the communal shelter after feeding. The caterpillars make careful comparisons of alternative pathways at choice points and select newer and stronger trails over older and weaker trails. Differential marking of new and established trails during nightly forays, coupled with sensory discrimination of trails by strength and age, leads colonies to abandon old trails in favor of new trails. When applied at a rate as low as 2.5 × 10 −10 g/mm, caterpillars followed synthetic trails prepared from 5β-cholestane-3-one, a trail pheromone previously reported from the tent caterpillars (Malacosoma spp.). Although both Eucheira and Malacosoma mark with the tip of the abdomen and have near-identical sensitivites to 5β-cholestane-3-one, our study shows that Eucheira employs a relatively unsophisticated system of trail-based communication and does not recruit to food. The trail-based communication system of Eucheira appears to represent an early stage in the evolution of cooperative foraging that is derived from, and motivationally linked to, conflict behavior.
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  • 97
    ISSN: 1572-8889
    Keywords: radar tracking ; harmonic radar ; foraging flight ; Lepidoptera ; Agrotis segetum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 98
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    Journal of insect behavior 11 (1998), S. 343-359 
    ISSN: 1572-8889
    Keywords: Agrotis segetum ; Lepidoptera ; Noctuidae ; turnip moth ; reproduction ; sex ratio ; reproductive capacity ; sexual selection ; mate discrimination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We investigated the lifetime mating potential and the reproductive behavior of male and female turnip moths Agrotis segetum (Schiff.) under field and laboratory conditions. The sex ratio was 1 : 1 in a lab-reared population as well as in two wild populations. Males were capable of mating repetitively a relatively large number of times (mean of 6.7 ± 2.7 matings) when given access to new virgin females throughout their lifetimes. Females seldom mated more than once (mean ± 1.3 ± 0.6 matings), indicating a male-biased operational sex ratio. The mean potential lifetime mating was five times higher in males, while the coefficient of variance was lower in males. There was no differences in longevity between animals that were allowed to mate and animals not allowed to mate, indicating no direct costs or benefits of mating in physiological terms. In males, the number of matings was positively correlated with longevity, but this was not the case in females. Nor was there a correlation between the number of female matings and the number of fertilized eggs. There was a negative correlation between the number of eggs fertilized and the number of times males had previously mated, indicating that male ejaculates were limited. Male spermatophore size also decreased with number of achieved matings. Laboratory-reared females attracted males in the field throughout their lifetimes, with a peak at 3–7 days of age. Wild males, allowed to choose between pairs of caged females in the field, were attracted in equal numbers to females of different ages. Females did not show any mate-rejection behavior in the field. They mated with the first male that courted them. No incidence of mate replacement by males arriving later to already courted females were recorded.
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  • 99
    ISSN: 1432-2048
    Keywords: Key words: Chlorophyll antenna size ; D1 protein ; Dunaliella (photoinhibition) ; Electron transport ; Photoinhibition ; Photosystem II
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. We investigated the effect of photosynthetic electron transport and of the photosystem II (PSII) chlorophyll (Chl) antenna size on the rate of PSII photoinhibitory damage. To modulate the rate of photosynthesis and the light-harvesting capacity in the unicellular chlorophyte Dunaliella salina Teod., we varied the amount of inorganic carbon in the culture medium. Cells were grown under high irradiance either with a limiting supply of inorganic carbon, provided by an initial concentration of 25 mM NaHCO3, or with supplemental CO2 bubbled in the form of 3% CO2 in air. The NaHCO3-grown cells displayed slow rates of photosynthesis and had a small PSII light-harvesting Chl antenna size (60 Chl molecules). The half-time of PSII photodamage was 40 min. When switched to supplemental CO2 conditions, the rate of photodamage was retarded to a t1/2 = 70 min. Conversely, CO2-supplemented cells displayed faster rates of photosynthesis and a larger PSII light-harvesting Chl antenna size (500 Chl molecules). They also showed a rate of photodamage with t1/2 = 40 min. When depleted of CO2, the rate of photodamage was accelerated (t1/2  = 20 min). These results indicate that the in-vivo susceptibility to photodamage is modulated by the rate of forward electron transport through PSII. Moreover, a large Chl antenna size enhances the rate of light absorption and photodamage and, therefore, counters the mitigating effect of forward electron transport. We propose that under steady-state photosynthesis, the rate of light absorption (determined by incident light intensity and PS Chl antenna size) and the rate of forward electron transport (determined by CO2 availability) modulate the oxidation/reduction state of the primary PSII acceptor QA, which in turn defines the low/high probability for photodamage in the PSII reaction center.
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  • 100
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    Journal of chemical ecology 24 (1998), S. 1173-1186 
    ISSN: 1573-1561
    Keywords: Ants ; Camponotus rufipes ; Solenopsis geminata ; Dione junio ; Abanotes hylonome ; Lepidoptera ; Nymphalidae ; repellency ; defense
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We analyzed the behavioral responses of the ants Camponotus rufipes and Solenopsis geminata towards all instars of Dione junio and Abananote hylonome. We also analyzed ant behavior towards hexane extracts of larvae and extracts of the spines and neck glands of the fifth instars of both species and identified the chemical compounds present. Larvae of both species were repellent to ants from the first instar onward. Later instars survived ant attacks better than earlier instars. The spines and neck glands of the larvae influenced the behavior of C. rufipes. The chemical compounds contained in the hexane extracts of whole first and fifth instars and in the spines and neck glands of fifth instars were principally carboxylic acids and terpenes. Further bioassays confirmed the repellent effect of some of these acids toward ants.
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