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  • Lepidoptera  (357)
  • Hymenoptera  (201)
  • gene expression  (199)
  • Climate change
  • somaclonal variation
  • Springer  (797)
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  • Molecular Diversity Preservation International
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  • 1
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Carbon Balance and Management 12 (2017): 10, doi:10.1186/s13021-017-0077-x.
    Description: Determining national carbon stocks is essential in the framework of ongoing climate change mitigation actions. Presently, assessment of carbon stocks in the context of greenhouse gas (GHG)-reporting on a nation-by-nation basis focuses on the terrestrial realm, i.e., carbon held in living plant biomass and soils, and on potential changes in these stocks in response to anthropogenic activities. However, while the ocean and underlying sediments store substantial quantities of carbon, this pool is presently not considered in the context of national inventories. The ongoing disturbances to both terrestrial and marine ecosystems as a consequence of food production, pollution, climate change and other factors, as well as alteration of linkages and C-exchange between continental and oceanic realms, highlight the need for a better understanding of the quantity and vulnerability of carbon stocks in both systems. We present a preliminary comparison of the stocks of organic carbon held in continental margin sediments within the Exclusive Economic Zone of maritime nations with those in their soils. Our study focuses on Namibia, where there is a wealth of marine sediment data, and draws comparisons with sediment data from two other countries with different characteristics, which are Pakistan and the United Kingdom. Results indicate that marine sediment carbon stocks in maritime nations can be similar in magnitude to those of soils. Therefore, if human activities in these areas are managed, carbon stocks in the oceanic realm—particularly over continental margins—could be considered as part of national GHG inventories. This study shows that marine sediment organic carbon stocks can be equal in size or exceed terrestrial carbon stocks of maritime nations. This provides motivation both for improved assessment of sedimentary carbon inventories and for reevaluation of the way that carbon stocks are assessed and valued. The latter carries potential implications for the management of human activities on coastal environments and for their GHG inventories.
    Description: We acknowledge research support from ETH Zurich and the Swiss National Science Foundation.
    Keywords: Carbon stocks ; Sediments ; Oceans ; Climate change ; Exclusive Economic Zone ; Carbon inventory
    Repository Name: Woods Hole Open Access Server
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  • 2
    Publication Date: 2022-10-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Baltar, F., Bayer, B., Bednarsek, N., Deppeler, S., Escribano, R., Gonzalez, C. E., Hansman, R. L., Mishra, R. K., Moran, M. A., Repeta, D. J., Robinson, C., Sintes, E., Tamburini, C., Valentin, L. E., & Herndl, G. J. Towards integrating evolution, metabolism, and climate change studies of marine ecosystems. Trends in Ecology and Evolution. 34(11), (2019): 1022-1033, doi: 10.1016/j.tree.2019.07.003.
    Description: Global environmental changes are challenging the structure and functioning of ecosystems. However, a mechanistic understanding of how global environmental changes will affect ecosystems is still lacking. The complex and interacting biological and physical processes spanning vast temporal and spatial scales that constitute an ecosystem make this a formidable problem. A unifying framework based on ecological theory, that considers fundamental and realized niches, combined with metabolic, evolutionary, and climate change studies, is needed to provide the mechanistic understanding required to evaluate and forecast the future of marine communities, ecosystems, and their services.
    Description: This work arose from the international workshop IMBIZO 5: Marine biosphere research for a sustainable ocean: Linking ecosystems, future states and resource management, organized by the IMBeR (Integrated Marine Biosphere Research) Program, and held at the Woods Hole Oceanographic Institution in October 2017. In particular, this work was generated from the working group from Workshop 2: Metabolic diversity and evolution in marine biogeochemical cycling and ocean ecosystem processes. The constructive criticism of three reviewers on a previous version of the manuscript is gratefully acknowledged. F.B. was supported by a Rutherford Discovery Fellowship by the Royal Society of New Zealand. G.J.H. was supported by the Austrian Science Fund (FWF) project ARTEMIS (P28781-B21).
    Keywords: Marine ecosystems ; Niche ; Evolution ; Metabolism ; Climate change
    Repository Name: Woods Hole Open Access Server
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  • 3
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ambio 46, Supple. 1 (2017): 160-173, doi:10.1007/s13280-016-0870-x.
    Description: Long-term measurements of ecological effects of warming are often not statistically significant because of annual variability or signal noise. These are reduced in indicators that filter or reduce the noise around the signal and allow effects of climate warming to emerge. In this way, certain indicators act as medium pass filters integrating the signal over years-to-decades. In the Alaskan Arctic, the 25-year record of warming of air temperature revealed no significant trend, yet environmental and ecological changes prove that warming is affecting the ecosystem. The useful indicators are deep permafrost temperatures, vegetation and shrub biomass, satellite measures of canopy reflectance (NDVI), and chemical measures of soil weathering. In contrast, the 18-year record in the Greenland Arctic revealed an extremely high summer air-warming of 1.3°C/decade; the cover of some plant species increased while the cover of others decreased. Useful indicators of change are NDVI and the active layer thickness.
    Description: The Toolik research was supported in part by NSF Grants DEB 0207150, DEB 1026843, ARC 1107701, and ARC 1504006.
    Keywords: Alaska Toolik ; Climate change ; Ecological effects ; Greenland Zackenberg ; Medium pass filter ; Vegetation
    Repository Name: Woods Hole Open Access Server
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  • 4
    Publication Date: 2022-05-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hult, M., Charette, M., Lutter, G., Marissens, G., Henderson, P., Sobiech-Matura, K., & Simgen, H. Underground gamma-ray measurements of radium isotopes from hydrothermal plumes in the deep Pacific Ocean. Applied Radiation and Isotopes, 153, (2019): 108831, doi:10.1016/j.apradiso.2019.108831.
    Description: The radium isotopes 226Ra and 228Ra can provide important data on the dynamics of deep-sea hydrothermal plumes that travel the oceans for decades and have great impact on the ocean chemistry. This study focuses on parameters important for obtaining low detection limits for 228Ra using gamma-ray spectrometry. It is present at mBq-levels in samples collected during the US GEOTRACES 2013 cruise to the Southeast Pacific Ocean.
    Description: The work of the HADES-staff of Euridice at SCK•CEN is gratefully acknowledged. We are most grateful to Dr. Faidra Tzika for her work in the precursor to this project. Many thanks to Heiko Stroh for quality control and measurements in HADES. This research was supported in part by grants from the U.S. National Science Foundation, Ocean Sciences division (OCE-1232669 and OCE-1736277).
    Keywords: γ-ray spectrometry ; HPGe detectors ; Hydrothermal plume ; Climate change ; Underground laboratory ; GEOTRACES
    Repository Name: Woods Hole Open Access Server
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  • 5
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    Entomologia experimentalis et applicata 69 (1993), S. 145-155 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Diptera ; crystal proteins ; Cyt proteins ; pathogenesis ; cytotoxicity ; solubility ; receptor binding ; pore formation ; synergism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 6
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    Entomologia experimentalis et applicata 57 (1990), S. 77-83 
    ISSN: 1570-7458
    Keywords: Age ; pteridine ; Pectinophora ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé En chromatographie liqudde à haute performance (HPLC) à détection par fluorescence, 4 composés ptéridiniques: la xanthoptérine, l'isoxanthoptérine, la 6-bioptérine et la ptérine ont été décelés dans les têtes de P. scutigera Holdaway (Lep. Gelechiidae) adultes. Un autre composé, dénommé ‘xanthoptérine modifiée’, a été décelé aussi dans les têtes de papillons; de même l'isoxanthoptérine a été décelée dans les thorax et abdomens. Les concentrations de ces ptérines ont été dosées dans les têtes des papillons de 2 à 50 jours au laboratoire à 25°C. Les concentrations d'isoxatthoptérine ont été dosées dans les thorax et les abdomens de 2 à 40 jours. La xanthoptérine de la ‘xanthoptérine modifiée’ diminuent nettement avec l'âge, tandis que la ptérine diminue plus lentement et que la 6-bioptérine se maintient pratiquement sans changements. L'isoxanthoptérine diminue dans les têtes de mâles de 38,3 ng/tête à 2 j à 22,7 ng/tête à 50 j, mais chez les femelles les concentrations augmentent nettement de 41,2 ng/tête à 2 j à 150,4 ng/tête à 50 j. Des modifications de même type ont été observées dans les thorax et les abdomens des mâles et des femelles. Les modifications de concentration de la ‘xanthoptérine modifiée’ des têtes de papillons peuvent être utilisées pour évaluer l'âge physiologique de mâles et des femelles de P. scutigera. La confiance dans ces estimations peut être améliorée en se référant aux concentrations d'isoxanthoptérine dans les thorax des mâles et au rapport isoxanthoptérine/‘xanthoptérine modifiée’ dans les têtes de femelles.
    Notes: Abstract The amounts of four pteridine compounds, xanthopterin, isoxanthopterin, 6-biopterin and pterin and a further unidentified substance, termed ‘modified xanthopterin’, were determined in the heads of adult Pectinophora scutigera (Holdaway) (Lepidoptera: Gelechiidae), aged between 2 and 50 days and reared in the laboratory at 25°C. The level of isoxanthopterin was also determined in the thoraces and abdomens of moths aged between 2 and 40 days. The levels of xanthopterin, and ‘modified xanthopterin’ decreased markedly in the heads of males and females with increasing moth age, while those of pterin decreased more slowly and 6-biopterin remained largely unchanged. Isoxanthopterin decreased in male heads from 38.3 ng/head at 2 days to 22.7 ng/head at 50 days, but in females levels increased from 41.2 ng/head at 2 days to 150.4 ng/head at 50 days. Similar changes in the amounts of isoxanthopterin with increasing moth age were observed in male and female thoraces and abdomens. The results are discussed in relation to using pteridine compounds for estimating the physiological age of P. scutigera.
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  • 7
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    Entomologia experimentalis et applicata 61 (1991), S. 95-96 
    ISSN: 1570-7458
    Keywords: Swammerdamia pyrella ; Lepidoptera ; Yponomeutidae ; (Z)-5-tetradecenyl acetate ; (Z)-7-tetradecenyl acetate ; sex attractant ; field trapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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  • 8
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    Entomologia experimentalis et applicata 71 (1994), S. 185-192 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Indianmeal moth ; semiochemicals ; attraction ; oviposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Substrates contaminated by wandering fifth instar larvae ofPlodia interpunctella (Hübner) (Lepidoptera: Pyralidae) elicit oviposition by conspecific female moths, and larval rearing diet enhances oviposition and also induces upwind flight. Two-choice oviposition assays determined that four-day-old gravid femaleP. interpunctella preferred to lay eggs on dishes containing cornmeal-based rearing diet compared to empty dishes. Pieces of cheesecloth contaminated by fifth instar larvae elicited more oviposition than untreated cheesecloth or dishes with food. The combination of larval contamination and food was preferred over food only or larval contamination only in both two- and four-choice experiments. The factor(s) in larval contamination responsible for eliciting oviposition in female moths was extracted in hexane, confirming that organic semiochemicals are responsible for the effect. The oviposition-eliciting activity of larval contamination was retained on cheesecloth for up to 30 days following treatment with larvae, suggesting the active component(s) is stable and of low relative volatility. In two-choice windtunnel bioassays female moths initiated flight only when rearing food was present in one of the treatments, and they displayed the highest landing responses to a combination of larval contamination and food. Earlier work onP. interpunctella and related pyralid species found that larval contamination due to secretions from the mandibular glands acted as both a spacing pheromone for wandering larvae and as a kairomone for host-seeking parasitoid wasps. The present study suggests that the same or a similar secretion acts as an oviposition-eliciting pheromone for conspecific females.
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  • 9
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Braconidae ; Lepidoptera ; Pieridae ; cabbage ; tritrophic interactions ; semiochemicals ; host-habitat location ; foraging behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Upon initiating a research project on the role of volatile infochemicals in the tritrophic system Cotesia (= Apanteles) glomerata (L.)-Pieris brassicae (L.)-cabbage, a bioassay was developed to investigate the response of C. glomerata. The bioassay should be effective in terms of high responsiveness and minimum variability and constructed through a comparative approach. Twenty seven treatments, organized in a factorial randomized block design, compared the effect of three bioassay set-ups (glasshouse flight chamber, wind-tunnel and Y-tube olfactometer), three parasitoid age groups (1–2, 4–5 and 8–9 days old females), three pre-treatment experiences (naive, damage experienced and oviposition experienced wasps) and the day-to-day effect on response of C. glomerata to clean cabbage (CC) and planthost complex (PHC) in a dual choice test. The best results with regard to the strength and consistency of response to the PHC were obtained in the glasshouse flight-chamber by 4–5 days old female wasps with either damage or oviposition experience (94 and 90%, respectively). It is therefore recommended as a suitable bioassay for studying the role of volatile infochemicals in host-habitat location by C. glomerata. A day-to-day variation in response was found in the glasshouse and wind-tunnel. It was correlated with the direction of change in barometric pressure within the time period of the experiment, showing that steadily increasing atmospheric pressure yields a significantly higher response than steadily decreasing or fluctuating barometric flux. To control for the day effect it is suggested to conduct further experiments in a block design, having day as a block. Several aspects of the infochemical ecology of C. glomerata are discussed.
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  • 10
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    Entomologia experimentalis et applicata 72 (1994), S. 173-180 
    ISSN: 1570-7458
    Keywords: feeding performance ; diapausing propensity ; genetic correlation ; heritability ; host-range ; insect-plant interactions ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Evolutionary constraints on the ability of herbivores to efficiently use a set of phytochemically similar hosts, while maintaining a high performance on phytochemically different hosts, are central in explaining the predominance of host specialization in phytophagous insects. Such feeding trade-offs could be manifested within insect populations as negative genetic correlations in fitness on different host species. We tested the hypothesis that feeding trade-offs were present within a population of the obliquebanded leafroller,Choristoneura rosaceana (Harris). Components of fitness were measured in families originating from an apple orchard that were fed on four host-plant species in the laboratory. Under the conditions of this experiment, all across-host genetic correlations were strongly positive, suggesting that this population comprised true generalists. With the exception of diapausing propensity, the heritability of the fitness components tended to be lower in caterpillars fed on apple leaves than in insects fed other hosts. This suggests a constraint on the selective response of the fitness components in the orchard environment.
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  • 11
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    Entomologia experimentalis et applicata 73 (1994), S. 289-297 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; parasitoid ; C. rubecula ; foraging behaviour ; specialist ; synomones ; infochemical use ; tritrophic interactions ; olfaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of volatile stimuli in the long-range host-searching behaviour of the specialist parasitoidCotesia rubecula Marshall (Hymenoptera: Braconidae) was studied. Components from the plant-host-complex Brussels sprouts (Brassica oleracea L. var.gemmifera (DC.) Schulz. cv. ‘Titurel’)-Pieris rapae L. (Lepidoptera: Pieridae) were compared for their attractiveness in dual choice tests in a windtunnel. Stimuli from cabbage plants that were mechanically damaged or damaged byP. rapae caterpillars were more attractive to this parasitoid species than stimuli emitted by the host larvae or their faeces. Parasitoids preferred leaves from the plant-host-complex over artificially damaged leaves. Undamaged cabbage plants were the least attractive to the foraging females. These results indicate that in-flight searching behaviour ofC. rubecula is guided by plant-derived information and that for this specialist species more reliable and specific host-derived cues play a minor role at longer distances.
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  • 12
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    Entomologia experimentalis et applicata 69 (1993), S. 33-39 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Aphidiinae ; aphid ; sex pheromone ; parasitoid ; Praon volucre ; Aphidius rhopalosiphi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Laboratory and field experiments provided evidence for the release of sex pheromones by virgin femalePraon volucre Haliday andAphidius rhopalosiphi De Stefani-Perez (Hymenoptera: Braconidae, Aphidiinae). In Petri dish biosassays, rubber or vermiculite models treated with crude virgin female extracts were frequently approached by males and elicited rapid wing-fanning behaviour and copulation attempts. Delta-shaped water traps containing live virgin females caught large numbers of conspecific males when placed in winter wheat crops. Trapping slightly below crop height resulted in higher catches than trapping above the crop canopy.
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  • 13
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    Entomologia experimentalis et applicata 72 (1994), S. 25-31 
    ISSN: 1570-7458
    Keywords: diapause induction ; photoperiod ; temperature ; Phyllonorycter blancardella ; spotted tentiform leafminer ; Lepidoptera ; Gracillariidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The role of photoperiod and temperature in the induction of overwintering diapause inPhyllonorycter blancardella (F.) (Lepidoptera: Gracillariidae) was examined in the laboratory and field using leafminers from commercial apple orchards in Ontario, Canada.P. blancardella exhibited a long-day response to photoperiod: long daylengths resulted in uninterrupted development whereas short daylengths induced diapause. The estimated critical photoperiod for diapause induction was L14.25∶D9.75. The larvae of leafminers destined to enter diapause took ca. 3× longer to complete development than the larvae of non-diapausing leafminers. The development prolonging effect of photoperiod decreased with decreasing daylength. Temperature modified the diapause inducing effect of photoperiod. At L14.25∶D9.75, diapause incidence was similar at 15 and 20°C but was lower at 25°C. Photoperiod also altered the normal relationship between development rate and temperature. At L14.25∶D9.75, the duration of larval development of diapausing leafminers was similar at 15, 20 and 25°C. Temperature alone is unlikely to have a role in the induction of diapause because leafminers exposed to natural late summer and fall temperature regimes and L16∶D8 did not enter diapause.
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  • 14
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Ectomyelois ceratoniae ; carob moth ; host-finding ; Phoenix dactylifera ; dates ; gas chromatography-electrophysiology ; mass spectrometry ; wind tunnel ; attraction ; volatiles ; headspace
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four volatile compounds emitted from fungus-infected date fruit,Phoenix dactylifera L., were identified using coupled gas chromatographic-electroantennographic recordings, coupled gas chromatographic-mass spectrometric analysis, electroantennographic assays of synthetic standards, and wind tunnel bioassays. These compounds were ethyl hexanoate, ethanol, acetaldehyde, and 2-phenylethanol. Wind tunnel bioassays showed that ethyl hexanoate was capable of stimulating upwind flight and landing on the source by mated female carob moths,Ectomyelois ceratoniae (Zeller). Addition of both ethanol and acetaldehyde to ethyl hexanoate resulted in an increase in attraction to a level similar to that found for date fruits. No such effect was noted for additions of 2-phenylethanol at the dosages tested. In this study, it appears that ethyl hexanoate is a dominant olfactory stimulant and attractant for mated female carob moths, and represents a novel compound with regard to previously identified lepidopteran host odor attractants.
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  • 15
    ISSN: 1570-7458
    Keywords: Cruciferae ; Brassica oleracea ; tritrophic interactions ; Pieridae ; Hymenoptera ; parasitoids ; Cotesia ; kairomones ; headspace ; GC-MS ; chemical composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Headspace composition, collected from intact cabbage plants and cabbage plants infested with eitherPieris brassicae L. orP. rapae L. (Lepidoptera: Pieridae) first instar larvae, was determined by GC-MS. Twenty-one volatiles were identified in the headspace of intact plants. Twenty-two volatiles were identified in the headspace of plants infested byP. brassicae larvae, 2 of which, Z-3-hexenyl butyrate and Z-3-hexenyl isovalerate, were not detected in the headspace of either intact orP. rapae damaged plants. In the headspace of the latter, 21 compounds were identified, all of which which were also produced by intact plants. No significant quantitative differences were found between headspace composition of the plants damaged by one or the other caterpillar species. Major differences between intact and caterpillar-damaged plants in contribution to the headspace profile were revealed for hexyl acetate, Z-3-hexenyl acetate, myrcene, sabinene and 1,8-cineole. The larval endoparasitoidCotesia glomerata L. was attracted by the volatiles emanating fromB. oleracea damaged byP. brassicae first instar larvae.C. rubecula L., a specialized larval endoparasitoids ofP. rapae, was attracted by the volatiles released from theB. oleracea-P. rapae plant-host complex. This shows that cabbage plants kept under the conditions of headspace collection produce attractive volatiles for both parasitoids.
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  • 16
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    Entomologia experimentalis et applicata 73 (1994), S. 211-220 
    ISSN: 1570-7458
    Keywords: Eurytoma amygdali ; Hymenoptera ; Eurytomidae ; host selection ; chemical stimuli ; olfactory response ; aggregation ; oviposition ; almond
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Females of the almond seed wasp,Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae), responded in an olfactometer positively to odours from almond flowers and unripe fruits, but not to almond leaf odours and odours from flowers and unripe fruits of certain other nonhostPrunus species. Males responded to none of these odours. Extracts of undamaged unripe almond fruits (using ethanol, methanol, acetone, hexane, dichloromethane, or petroleum ether) stimulated female aggregation on glass surfaces treated with these extracts; in addition, certain fruit extracts (ethanol, methanol, or acetone) stimulated oviposition. Extracts of undamaged almond leaves (ethanol, methanol, or acetone) and flowers (ethanol or methanol) also stimulated female aggregation and oviposition. Aggregation and oviposition in response to an ethanol extract of almond fruits was intense in females aged 5 to 14 days and from 12∶00 to 18∶00h (photophase between 06∶00 and 20∶00). Certain almond fruit (ethanol, methanol, acetone or hexane) and flower extracts (ethanol or methanol) also provoked female response in the olfactometer. The results strongly suggest that certain chemical stimuli emanating from parts of the almond tree play a major role in host selection and oviposition. Some of the extracts tested may be a good source for the isolation, identification and synthesis of compounds stimulating attraction, aggregation and oviposition in nature. *** DIRECT SUPPORT *** A3414024 00003
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  • 17
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    Entomologia experimentalis et applicata 68 (1993), S. 1-7 
    ISSN: 1570-7458
    Keywords: Hybridoma ; detectability period ; venom ; predation ; serology ; protease ; Vespidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to derive quantitative estimates of predation rate from serological gut analysis data, one must have an estimate of the interval during which a meal can be detected after feeding. In practice this has turned out to be ‘Dmax,’ defined as ‘...the time from finishing a meal until that meal could just no longer be detected in any individuals.’ However Dmax substitutes an absolute limit for what is really a continuous variable with significant variation. We examined this problem in a study of the detectability ofHelicoverpa zea Boddie (Lepidoptera: Noctuidae) fifth instar remains in the guts ofPolistes metricus Say (Hymenoptera: Vespidae). Wasps were maintained onTrichoplusia ni (Hübner) (Lepidoptera: Noctuidae) fifth instars before being fed a singleH. zea fifth instar. They were killed and frozen at 0, 24, 48 and 96 h intervals, with those held for more than 24 h fed a singleT. ni fifth instar at 24 h intervals in order to simulate continued feeding. Wasp abdomens were assayed by immunodot, using a monoclonal antibody toH. zea arylphorin. There was a logarithmic decay in the proportion ofP. metricus positive over time, a singleH. zea fifth instar meal having a detectability half-life of 19.4 h at field temperatures. If prey antigen detectability decays exponentially, then a detectability half-life is a more appropriate unit of detectability than an absolute detectability period.
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  • 18
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    Entomologia experimentalis et applicata 68 (1993), S. 59-69 
    ISSN: 1570-7458
    Keywords: oviposition ; Pieris rapae ; Pieris napi oleracea ; Cruciferae ; Lepidoptera ; Pieridae ; stimulant ; deterrent ; insect-plant interaction ; host range
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oviposition responses ofPieris rapae L. andP. napi oleracea Harris to nine crucifers, one Capparidaceae and one Tropaeolaceae were directly compared under controlled conditions. Chemical fractions from these plants were also tested on both insects for the presence of oviposition stimulants or deterrents. The results showed that plant chemistry is a key factor in differential selection of potential hosts by thesePieris species. Some plant species were equally acceptable to bothPieris species. However,P. rapae preferred cabbage over most test plants whereasP. napi oleracea strongly preferred plant species that were avoided byP. rapae. The observed preferences were explained in most cases by the presence of stimulants and deterrents in extracts of the plants. The twoPieris species have apparently evolved differential sensitivities to the chemical stimuli that trigger or deter oviposition. The balance of positively and negatively interpreted sensory signals evoked by plant chemicals obviously plays an important role in acceptance or rejection of a plant by both species. The role of specific glucosinolates and differing structure-activity relationships is suggested.
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  • 19
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    Entomologia experimentalis et applicata 68 (1993), S. 219-229 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Aphidiidae ; Homoptera ; Aphididae ; Schizaphis graminum ; wheat ; tritrophic interactions ; learning ; host-habitat location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of experience on the responsiveness of the aphidiid parasitoidLysiphlebus testaceipes (Cresson) (Hymenoptera: Aphidiidae) to host-associated cues was investigated using a wind-tunnel bioassay. Naive females were able to discriminate between uninfested wheat (Triticum aestivum L.) and wheat infested withSchizaphis gramimum (Rondani) (Homoptera: Aphididae), but oviposition experience significantly increased the parasitoid's propensity to respond to aphid-infested plants with upwind, targeted flight. The behavioural change associated with such experience was acquired rapidly (within five minutes) and persisted for at least 24 h. The parasitoid could be successfully conditioned to associate a novel odour with the presence of hosts, suggesting that the increase in response to aphid-infested plants which occurs as a result of experience is probably due to associative learning of olfactory cues from the plant-aphid complex.
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  • 20
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    Entomologia experimentalis et applicata 67 (1993), S. 57-64 
    ISSN: 1570-7458
    Keywords: Cydia pomonella ; codling moth ; mating disruption ; (E,E)-8,10-dodecadien-1-ol ; pheromones ; apple ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polyethylene dispensers (Shin Etsu) containing 172 ml of the sex pheromone, (E, E)-8,10-dodecadien-1-ol (63%), dodecenol (31%) and tetradecenol (6%), of codling moth (CM),Cydia pomonella (L.), were placed in apple orchards in Virginia. Two blocks of about 2 ha each were treated in 1989, and three in 1990. Dispensers were placed in trees at a density of 1000/ha shortly after apple bloom. Male orientation to pheromone traps was almost totally disrupted (a few males were captured at high population densities). In 1989, the Daleville pheromone-treated block had 0.9% and 0.8% CM-injured fruit in the center and edge, respectively; 0% and 39.5% injured fruit were found in the conventional control and abandoned blocks, respectively. The Criglersville orchard (‘organically’ managed, with high CM density) CM harvest injury was 16.0%, 16.5%, 34.5%, and 26.5% in the pheromone-treated center and edge, organic control and abandoned blocks, respectively. In 1990, the Daleville CM harvest injury was 4.7%, 7.3%, 1.1%, 0.3% and 58%, in the pheromone-treated center and edge, control center and edge, and abandoned blocks, respectively (possible reasons for the high injury in this block are discussed). Harvest injury in the Fincastle pheromone-treated and control blocks were 0.7% and 0%, respectively. The Criglersville orchard yielded 17%, 19% and 20% CM-injured fruit at harvest in the pheromone-treated, organic control and abandoned blocks, respectively. Pheromone release rate was calculated as 37 mg/ha/h in 1989.
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  • 21
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    Entomologia experimentalis et applicata 67 (1993), S. 183-192 
    ISSN: 1570-7458
    Keywords: symbionts ; thelytoky ; arrhenotoky ; Hymenoptera
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    Topics: Biology
    Notes: Abstract Microbe-associated parthenogenesis (thelytoky) has been discovered in nineTrichogramma species, parasitoids of mainly lepidopteran eggs. Parthenogenetic and bisexual conspecifics co-occur in many field populations. As an initial step to understand the dynamics of these two reproductive strategies we studied the effect of microbe-associated parthenogenesis on fecundity. The fecundity of two parthenogenetic isofemale lines ofT. pretiosum and one ofT. deion was compared with bisexual lines derived from them by antibiotic treatment. In all three cases parthenogenetic females were less fecund over their lifetime than bisexual females. Also, parthenogenetic females produced fewer daughters in two cases and in one case a similar number of daughters as their respective bisexual counterparts. The lack of mating and insemination was excluded as an explanation for the reduced fecundity of parthenogenetic females, because mated and virgin parthenogenetic females produce the same number of offspring. Antibiotic treatment can also be excluded because females of field-collected bisexual line treated with antibiotics produced the same number of offspring as untreated females. The reduced fecundity of parthenogenetic females was caused by a lower number of eggs being laid rather than by a greater developmental mortality. Parthenogenetic females produced less daughters than bisexual females when host availability was not limiting, but when host availability was severely limited, parthenogenetic females produced more daughters than the bisexual females.
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  • 22
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    Entomologia experimentalis et applicata 67 (1993), S. 233-239 
    ISSN: 1570-7458
    Keywords: inbreeding ; colonization ; isofemale line ; Drosophila ; Diptera ; Leptopilina boulardi ; Cynipidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé D. melanogaster (Meigen) a été utilisé pour tester la capacité des lignées isofemelles à conserver la variabilité génétique d'une population naturelle. Deux types d'expériences ont été réalisées. L'une a consisté à déterminer la variabilité génétique de 3 locus enzymatiques pour 32 lignées isofemelles à la première et à la 23ème génération d'élevage au laboratoire. L'autre a consisté à tester la capacité des larves à éliminer un parasitoïde par le processus d'encapsulation après 8 années d'élevage au laboratoire. D'une façon générale, certaines lignées isofemelles perdent de la variabilité durant les 23 générations de l'étude. Mais la fréquence globale des allèles reste inchangée si l'on considère l'ensemble des 32 lignées. Le seul allèle rare observé a également été conservé. Les modifications des fréquences allèliques à chacun des locus ont lieu de façon indépendante les unes des autres. La variabilité génétique d'un caractère biologique, la capacité des larves à encapsuler le parasitoïde, a également varié, mais elle a pu être restaurée à un niveau proche de la population initiale en rassemblant plusieurs individus de chacune des lignées.
    Notes: Abstract Drosophila melanogaster (Meigen) was used to test the power of isofemale lines in preserving genetic variability. We performed experiments in two ways. One series consisted of measuring the genetic variability for three enzymatic loci in 32 isofemale lines, in the first and 23rd generations of culture. In the second series, we tested the capacity of the larvae to eliminate a parasitoid by encapsulation after eight years of laboratory breeding. In general, individual isofemale lines appeared to change during the 23 generations of the study, but the global frequency of these alleles among the 32 isofemale lines stayed relatively unchanged. The only rare allele observed was also conserved. Changes in allozyme frequencies at any one locus were independent of those at other loci. Genetic variation of a biological trait, the capacity of the larvae to encapsulate a parasitoid, also changed, but it could be restored to a level close to that of the starting population by mass hybridizing together individuals of each line.
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  • 23
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    Entomologia experimentalis et applicata 70 (1994), S. 295-298 
    ISSN: 1570-7458
    Keywords: forest tent caterpillar moth ; Malacosoma disstria ; fluctuating asymmetry ; survival ability ; pest management ; Lepidoptera
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    Notes: Abstract Fluctuating asymmetry of the first tarsal segment of the proleg of the forest tent caterpiller mothMalacosoma disstria Hbn. (Lepidoptera: Lasiocampidae) was significantly inversely related to survival ability in the lab. The monitoring of population levels of fluctuating asymmetry could have important implications in pest management of this and other species by providing an indication of the health of a population.
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    Entomologia experimentalis et applicata 71 (1994), S. 33-39 
    ISSN: 1570-7458
    Keywords: Helicoverpa zea ; Noctuidae ; Lepidoptera ; Eucelatoria bryani ; Tachinidae ; Diptera ; host-parasitoid relationship ; host regulation
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    Topics: Biology
    Notes: Abstract The parasitoidEucelatoria bryani Sabrosky regulates the larval behavior of its hostHelicoverpa zea (Boddie). Parasitized third, fourth and fifth instars burrow into the soil 0.7–3.4 days earlier than unparasitized larvae that normally enter the soil to pupate at the end of the fifth and final larval instar. Parasitized third instars molt once then burrow as fourth instars, one instar earlier than normal. WhenE. bryani pupariated on the soil surface in the field, none survived to the adult stage. However,E. bryani adults emerged from 49.2% of hosts that had burrowed into the soil. By accelerating the timing ofH. zea burrowing behavior and causing host larvae to enter the soil before death,E. bryani ensures its pupariation in an environment with improved protection against natural enemies and lethal temperatures.
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    Entomologia experimentalis et applicata 61 (1991), S. 159-168 
    ISSN: 1570-7458
    Keywords: Feeding ; behaviour ; chemosensory ablation ; Manduca sexta ; Lepidoptera ; bilateral sensory input ; input redundancy
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    Notes: Abstract The function of bilateral chemosensory input in food discrimination was examined using larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera: Sphingidae), in 2-choice preference tests. Larvae having three different complements of chemosensory organs remaining after microsurgery were tested: unoperated, unilaterally-ablated, and bilaterally-ablated. Discrimination between Solanum pseudocapsicum (L.) and Pelargonium hortorum (Bailey) was reduced after unilateral removal of chemosensory organs. A similar effect was found in tests offering larvae a choice between one plant species or an ethanolic extract of S. pseudocapsicum and wetted filter paper, indicating an impaired food detection. These results demonstrate that both sets of chemosensory organs are required for normal feeding decisions about these plants. Six additional plant species were each tested against wetted filter paper. The function of bilateral chemosensory input in food discrimination varies with the plant species tested. Bilateral chemosensory input is required for discrimination of Vigna sinensis (Savi) and Raphanus sativus (L.), but not for that of Lycopersicon esculentum (Mill.), Datura innoxia (L.), Brassica napus (L.), and Canna generalis (Bailey). Discrimination of V. sinensis, S. pseudocapsicum, and P. hortorum by unoperated larvae is twice as strong as that by unilaterally-ablated larvae, suggesting algebraic addition of unilateral sensory inputs. For R. sativus unilateral input does not mediate discrimination, but bilateral input does, indicating sensory processing which may be more than additive. These results show that information mediated by bilateral chemosensory organs of M. sexta is not redundant in mediating feeding decisions, but provide the necessary sensory input for normal discrimination. This suggests that, for some plant species, feeding decisions are based on both qualitative and quantitative aspects of chemosensory input. No difference in preferences between left-sided and right-sided operated larvae were observed which suggests functional duplication of each set of unilateral chemosensory organs. Possible neural mechanisms underlying feeding decisions mediated by bilateral versus unilateral chemosensory inputs are discussed.
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  • 26
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Papilionidae ; Zerynthia ; Aristolochia ; herbivory ; phenology ; nutritional indices
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    Notes: Abstract The main host plants of the butterflyZerynthia rumina L. (Lepidoptera: Papilionidae) in southern Spain occur in different habitats and in general do not grow sympatrically. Therefore, each single local butterfly population uses the particular host available within its range.Aristolochia longa L. is a tuberous perennial herb available only in the spring, whileA. baetica L. is an evergreen perennial vine with indeterminate growth. However, because of the toughness of older leaves, newly hatched larvae feed only on new leaves ofA. baetica, and most of these leaves are produced well before the larvae hatch. In laboratory experiments, caterpillars feeding on either new or matureA. longa leaves grew faster and converted food into biomass more efficiently than those feeding on newA. baetica leaves. These differences are related to variation in nutritional quality among the host plants. Estimates of butterfly abundance were lower in sites whereZ. rumina usesA. baetica, compared with those where the host isA. longa. The potential differential effect of these two food plants on the densities of local butterfly populations relying on them is discussed here.
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    Entomologia experimentalis et applicata 63 (1992), S. 3-12 
    ISSN: 1570-7458
    Keywords: Feeding ; behaviour ; food preference induction ; diets ; Manduca sexta ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Diet-induced changes in food preference by fifth instar larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera, Sphingidae), were examined. Two groups of larvae with different diet experience were used: larvae reared on a host or on an acceptable non-host plant species. Each group of larvae was offered a choice between leaf discs from each rearing plant species (2-plant choice test) and food preference was measured as the consumption of one plant species relative to that of the other plant species. Diet-induced changes in preferences were larger with the host versus acceptable non-host plant pairs Solanum pseudocapsicum (L.) versus Raphanus sativus (L.), Lycopersicon esculentum (Mill.) versus Vigna sinensis (Savi), and Datura innoxia (L.) versus V. sinensis than with the host versus host plant pairs L. esculentum versus Capsicum annuum (L.) and L. esculentum versus D. innoxia. To examine how much the food preference had been altered for each test plant species alone, two other groups of larvae were offered a choice between leaf discs from a single plant species and filter paper discs laced with distilled water (1-plant choice test). Larvae preferred the dietary plant species more strongly than the non-dietary plant species in tests using the following plant species: for C. annuum with C. annuum and L. esculentum as diets, for V. sinensis with V. sinensis and L. esculentum or D. innoxia as diets, and for R. sativus with R. sativus and S. pseudocapsicum as diets. The preference for the hosts L. esculentum and D. innoxia did not change significantly after rearing larvae on different hosts or on an acceptable non-host. Thus, diet-induction by M. sexta larvae results in an enhancement of preference for the dietary plant species which is much stronger with acceptable non-hosts than with hosts.
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  • 28
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Braconidae ; Cotesia marginiventris ; parasitoid ; host searching ; allelochemicals ; plant synomones ; leaf damage ; frass ; flight tunnel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'hyménoptèreC. marginiventris Cresson, parasite solitaire, est connu comme étant attiré par les odeurs liées à l'hôte émises par un complexe de chenilles consommant des feuilles. La source exacte de ces substances attractives restait encore à déterminer. Pour cela, des expériences en tunnel de vol ont été réalisées dans lesquelles différents composés du complexe plante et hôte ont été testés individuellement et en combinaisons diverses. Les 3 composés testés ont été: 1) des plantules de maïs endommagées par des chenilles deSpodoptera exigua (BAW); 2) des excréments produits par les chenilles de BAW consommant du maïs; 3) des chenilles de BAW en l'absence de plantes et d'excréments. Les plantes endommagées ont été significativement plus attractives que les excréments ou les chenilles. En expériences de choix, les excréments étaient plus attractifs que les chenilles. Différentes combinaisons de ces 3 composantes principales ont montré que l'attractivité augmentait quand les chenilles étaient associées à des feuilles endommagées. Ajouter des excréments n'augmentait pas significativement l'attractivité. Quand des chenilles étaient associées avec des feuilles endommagées, mais en présence d'écran les empêchant de consommer les feuilles, l'attractivité était celle des feuilles endommagées seules. Des feuilles de maïs n'ayant jamais été exposées aux dégâts des chenilles étaient à peine attractives. On peut en conclure que les feuilles endommagées par les chenilles sont la principale source de substances volatiles qui orientent le parasitoïdeC. marginiventris vers le voisinage de ses hôtes. La consommation active par les chenilles augmente probablement la quantité de substances émises par les plantes, ce qui se traduit par une attractivité accrue. Les substances volatiles des plantes jouent un rôle dans la découverte de l'habitat de l'hôte par les parasitoïdes. De plus en plus d'éléments suggèrent qu'une interaction sophistiquée entre hôte, plante et parasitoïde sera éventuellement révélée.
    Notes: Abstract Single and dual choice tests in a flight tunnel revealed that plants damaged by host larvae are the main source of the volatiles that attract females of the parasitoidCotesia marginiventris (Cresson) to the microhabitat of its hosts. Frass and host larvae, the other two major components of a complete plant-host complex, were significantly less attractive than the damaged seedlings; frass alone was more attractive than larvae alone. However, a recombination of larvae with the damaged seedlings was significantly more attractive than the damaged leaves alone, or damaged leaves with frass. This was due to the additional feeding damage done by the larvae. The role of plants in the host-finding behaviour of parasitoids is discussed.
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    Entomologia experimentalis et applicata 58 (1991), S. 165-174 
    ISSN: 1570-7458
    Keywords: Eurytoma amygdali ; Hymenoptera ; Eurytomidae ; host marking pheromone ; host discrimination ; oviposition behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des expériences de laboratoire et des observations concernant le comportement de ponte de Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae) ont montré que, immédiatement après la ponte, les femelles déposent une phéromone de marquage de l'hôte en trainant le bout de leur abdomen sur la surface de l'amande. Cette phéromone les rends capable de distinguer les fruits infectés des non-infectés dt de sélectionner pour la ponte les derniers. Apparemment, la fonction principale de cette phéromone est la prévention de la répétition des ovipositions dans les fruits déjà infectés et la répartition uniforme des oeufs dans les amandes, contribuant ainsi à la meilleure utilisation des ressources disponsibles pour le développement des larves. Des expériences de deux choix entre des fruits de différents traitements ont montré que la phéromone pouvait être perçue par les femelles par le direct contact et, quand elle était à hautes concentrations, par olfaction d'une courte distance. La phéromone était présente dans l'abdomen et dans le thorax des femelles, et bien qu'elle soit soluble à l'eau, elle ne pouvait pas s'éloigner entièrement par lavage des amandes sérieusement infectées à l'eau. Les observations ont démontré qu'après un numéro de 3.7 visites successives sur des amandes portant de la phéromone les femelles s'éloignaient du lieu de ponte en marchant ou, le plus souvant, en s'envolant, ce qui suggère que la phéromone contribue à la dispersion des femelles.
    Notes: Abstract Laboratory experiments and observations on the oviposition behaviour of the almond seed wasp Eurytoma amygdali Enderlein (Hymenoptera, Eurytomidae) revealed that the females of this species deposit a host-marking pheromone, immediately after an oviposition, by dragging the tip of their abdomen on the fruit surface. This pheromone enables them to discriminate between the infested and uninfested fruit and to select for oviposition the latter. Its primary function is apparently the prevention of repeated ovipositions in already infested fruit, thus contributing to the optimal utilisation of the available resources for larval development. The responses of individual females to different treatments of almonds, in a series of two-choice tests, revealed that the pheromone can be perceived by the females on direct contact and, when at high concentrations, also olfactorily from a short distance. The pheromone was present inside the abdomen and thorax of females but not of males, and, although water soluble, could not be entirely removed from heavily infested almonds when rinsed with water. Direct observations revealed that after an average of 3.7 successive visits to pheromone-bearing almonds, females were induced to walk or, most often, fly away from the experimental set-up. This suggests that the pheromone may also contribute to the dispersion of the wasps.
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    Entomologia experimentalis et applicata 58 (1991), S. 267-277 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Ichneumonidae ; Campoletis sonorensis ; parasitoid ; host microhabitat ; synomones ; wind tunnel ; experience
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract The host microhabitat location behavior of females of the generalist parasitoid Campoletis sonorensis (Cameron) (Hymenoptera: Ichneumonidae) was studied in a wind tunnel. Visual cues associated with the host plant cotton, Gossypium hirsutum L., were important and significantly more parasitoids completed flights to a damaged 4-leaf cotton plant bearing a Heliothis virescens (F.) (Lepidoptera: Noctuidae) larva and frass than to a similarly damaged single leaf with frass and a larva. This difference in completed flights was not due to differences in amounts of volatiles released by the two stimuli. Both naive and experienced parasitoids responded differently to an undamaged cotton leaf, a mechanially damaged leaf, a naturally damaged leaf with the host removed and a naturally damaged leaf with a host larva. Parasitoids completed significantly fewer flights to the undamaged sources of volatiles than to damaged sources of volatiles. Experienced females responded strongly to all types of damage. The number of flights completed by naive females to the three types of damage differed but not significantly and was less than the number completed by experienced females. Components of the preflight experience were varied to determine which factors were responsible for the higher response of experienced females to the host/plant complex. Oviposition was the most important component of this experience. Contact with host frass or plant damage followed by oviposition did not increase the response over that exhibited by females allowed oviposition only. When frass or damaged plant material were contacted without subsequent oviposition, females completed fewer flights than naive females.
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  • 31
    ISSN: 1570-7458
    Keywords: Eurytoma amygdali ; Hymenoptera ; almond pest ; sex pheromone ; population monitoring ; chemical control
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    Notes: Abstract During the four years 1986–1989 we monitored an adult male population of the almond seed wasp, Eurytoma amygdali Enderlein, in the region of Thessaloniki, using sex pheromone traps, each containing 25 living virgin females. The emergence of adults from infested almonds of the previous year was also monitored in cages in the field, as well as the progress of fruit infestation and egg hatching in the almonds of the Retsou variety. Finally, two chemical control experiments were done against the newly hatched larvae to determine the optimal time for chemical control. During the 4-year study the start of adult captures occurred between April 13 and April 24, and the maximum between April 17 and May 11. In most cases, adult emergence from infested almonds in field cages began with a delay of 2 to 14 days in relation to the start of trap captures, and was affected by factors such as the date of cage installation. In all years most eggs hatched within 12–18 days of oviposition. A treatment with phosphamidon at a concentration of 0.06%, applied to tree branches of the Retsou variety with a hand-sprayer on May 23, 1987, when 54.1% of the eggs had hatched, was very effective (final infestation in July was 4.7% as compared to 89.1% of the untreated control). Three treatments with phosphamidon 0.06%, applied each on different tree branches, on May 14, 20, and 25, 1988, when the percentage of egg hatching was 7.8%, 65.3%, and 93.5%, respectively, were all very effective (final infestation in July was 1.6%, 3.6%, and 4.2% respectively, as compared to 93.6% of the untreated control). However, the presence of mines in the perisperm and outer endosperm, caused by the feeding larvae before they were killed, was more conspicuous in the almonds treated when the percentage of egg hatching was high. Our data suggest that the almond seed wasp can be effectively controlled with a single treatment of a systemic insecticide against the newly hatched larvae, preferably applied when the percentage of egg hatching is low to medium (between 10% and 50%). In the area of Thessaloniki, during 1986–89, 10% and 50% of egg hatching occurred about 21 and 27 days respectively after the beginning of male adult captures in pheromone traps.
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    Entomologia experimentalis et applicata 62 (1992), S. 87-91 
    ISSN: 1570-7458
    Keywords: Molting ; Lepidoptera ; nutritional indices
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  • 33
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Diprionidae ; chiral compounds ; behavioural activity ; attractant ; inhibitor
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    Notes: Abstract All eight optical isomers of 3,7-dimethyl-2-pentadecanyl acetate (diprionyl acetate), of high optical purity (〉 97.4%), were tested for a behavioural activity on male pine sawflies, Neodiprion sertifer (Geoffr.) (Hymenoptera: Diprionidae), in northern Europe. Males were strongly attracted to (2S,3S,7S)-diprionyl acetate. Addition of more than 0.1% of the (2S,3R,7R)-isomer reduced the catch and above 2% the attraction was completely inhibited. Contrary to what has been reported for North American and Japanese populations, so significant synergistic effect of small amounts of the (2S,3R,7R)-isomer could be demonstrated. The effects of addition of the other six optical isomers alone or in combinations, were also studied, but none was found to be a synergist. The (2S,3R,7S)-isomer had a weak inhibitory effect, and completely inhibited the attraction to the (2S,3S,7S)-isomer when applied in about equal amounts as the attractant. In some cases a reduction in catch was noted when other isomers were tested, but this could be attributed to the very small amounts of the inhibitory (2S,3R,7R)-isomer present in these isomers.
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    Entomologia experimentalis et applicata 65 (1992), S. 75-80 
    ISSN: 1570-7458
    Keywords: Pyralidae ; Lepidoptera ; Zea mays L. ; Chilo partellus ; susceptibility
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    Topics: Biology
    Notes: Abstract The resistance/susceptibility levels of ten maize (Zea mays L.) cultivars to neonates and 3rd-instar larvae of Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) were measured in the field and screenhouse experiments. The maize cultivars tested were: Inbred A, Mp 704, V-37, Population 10, Hybrid 511, Katumani Composite B, ER-29 SVR, Poza Rica 7832, ICZ2-CM, and MMV 400. Most cultivars were found susceptible to 3rd-instar larvae based on the incidence of dead heart symptoms, foliar feeding and stem tunnelling caused by stem borers in both the field and screenhouse experiments. However, the maize cultivars V-37, MMV 400 and Poza Rica 7832 sustained significantly lesser damage than the other cultivars when infested with neonates or 3rd instar larvae. The screenhouse experiments conducted with five maize cultivars, i.e. Inbred A, Mp 704, V-37, ER-29 SVR, and Poza Rica 7832 showed that neonates fed less on the resistant than the susceptible maize cultivars but feeding by the 3rd instars was equally high on all the maize cultivars except Mp 704 on which the larvae fed less than the others. In the cultivars infested with neonates, the mean period for 50% moth emergence P50 was longest on Mp 704 followed by Poza Rica 7832, ER-29 SVR, V-37 and Inbred A. In the cultivars infested with 3rd-instars, P50 was longest for Poza Rica 7832 followed equally by the remaining cultivars. On the basis of the evidence presented we here conclude that neonates of C. partellus are sensitive to the growth inhibiting effects of the resistant maize cultivars Mp 704, V-37, and Poza Rica 7832 but the older larvae are insensitive to these effects of Mp 704 and V-37 but not of Poza Rica 7832.
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    Entomologia experimentalis et applicata 67 (1993), S. 47-56 
    ISSN: 1570-7458
    Keywords: Platynota flavedana ; variegated leafroller ; Platynota ideausalis ; tufted apple bud moth ; Argyrotaenia velutinana ; redbanded leafroller ; mating disruption ; pheromones ; apple ; Lepidoptera ; Tortricidae
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    Notes: Abstract Mating disruption for control of variegated leafroller (VLR),Platynota flavedana (Clemens), tufted apple bud moth (TBM),P. ideausalis Walker, and redbanded leafroller (RBL),Argyrotaenia velutinana (Walker), was studied in Virginia apple orchards in 1989 and 1990. In 1989, each dispenser (1000/ha) contained 190 mg of 67.2%E11–14:Ac, 28.8%Z11–14:Ac, 1.4%E11–14:OH, 0.6%Z11–14:OH, and 2%Z9–12:Ac (a putative generic leafroller disruption blend). Trap captures of VLR, TBM and RBL were reduced by 97%, 51% and 55%, respectively. Average leafroller injury in the interior and edge of the pheromone block was 3.8% and 2.7%, respectively. The conventional control and abandoned blocks had 0.05 and 27.5% injury, respectively. Dispensers containingE11–14:OH (70%) andZ11–14:OH (30%) (close to the natural blend of VLR), more effectively disrupted orientation to pheromone traps by bothPlatynota spp. than did the generic blend. In 1990, dispensers containing 150 mg ofE11–14:OH (70%) andZ11–14:OH (1000/ha) were placed in two 2-ha blocks and one 4-ha block. One pheromonetreated block was sprayed in August with phosmet for codling moth, not timed for leafrollers. Trap captures of VLR and TBM were reduced by almost 100% and 69%, respectively. RBL captures were not reduced by VLR pheromone permeation. Injury fromPlatynota spp. in pheromone block middles and edges ranged from 0.3–1.7% and 0.3–2.3%, respectively. Injury in conventional blocks ranged from 0–1.1%. RBL injury in pheromone block middles ranged from 0–6.1%, and in edges, 1.7–4.8%. Injury in control blocks ranged from 0–1.1%. Combined leafroller injury in an abandoned block was 18% (s.e. 0.3). Release rates averaged 30 and 32 mg/ha/h for the VLR and generic pheromone dispensers, respectively.
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    Entomologia experimentalis et applicata 67 (1993), S. 79-85 
    ISSN: 1570-7458
    Keywords: Insecta ; Lepidoptera ; Noctuidae ; host-finding ; behavior ; oviposition
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    Topics: Biology
    Notes: Abstract Mated femaleTrichoplusia ni (Hubner) moths, when presented a choice of either undamaged cotton plants,Gossypium hirsutum L., or damaged plants (cut leaves or feedingT. ni larvae) in a flight tunnel, were most often attracted first to the damaged plants. However, these same moths oviposited primarily on the undamaged plants. In a similar test with cabbage plants,Brassica oleracea L., the presence of conspecific larvae decreased both attraction and oviposition. Cuts to cabbage leaves had no significant effect on attraction or oviposition. When presented one plant at a time, percentages of cabbage looper moths attracted were not affected by the presence of larvae on either cabbage or cotton plants, or by cuts to cabbage plant leaves. Percentages of moths attracted were, however, higher using cotton plants with cut leaves. The results suggest an important role for damage induced plant volatiles in host location as well as host acceptance byT. ni.
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  • 37
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    Entomologia experimentalis et applicata 68 (1993), S. 117-126 
    ISSN: 1570-7458
    Keywords: insect-plant interaction ; Lepidoptera ; Plutellidae ; crucifer ; sexual maturation ; reproductive diapause ; kairomone
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    Topics: Biology
    Notes: Abstract The influence of the presence of seedlings of a host plant, Oriental mustard,Brassica juncea (L.) Coss., on the calling behaviour and egg maturation in the diamondback moth,Plutella xylostella (L.), was investigated. In the presence of plants, females began calling at a younger age, began calling earlier in the night, and spent more time calling. Females which were kept with plants until after their first night of calling and then were isolated from plants, subsequently called less, at a level not significantly different from females which had never been exposed to plants. Of all females, both with and without plants, which were dissected at the end of the first night of calling (n=150), 93% contained mature eggs. Heavier females were significantly more likely to have mature eggs at adult emergence, to begin calling at a younger age and to spend more time calling on their first night of calling. The number of developed eggs in calling females was not significantly different in the presence or absence of host plants on the first night of calling. However, by the second night, females in the presence of plants contained significantly more eggs, indicating that the presence of plants accelerated egg maturation, both before and after the onset of calling.
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  • 38
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    Entomologia experimentalis et applicata 65 (1992), S. 165-170 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; stem borer ; suction trap ; behaviour ; maize ; dispersal ; pheromones ; activity
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    Topics: Biology
    Notes: Abstract The diel flight periodicity of the nocturnal moth Chilo partellus (Swinhoe) (Lepidoptera;Pyralidae) was measured in the laboratory using an actograph and in the field with suction traps. Females showed almost no flight activity on the night of eclosion. Flight activity of mated females peaked before midnight, the period of peak oviposition activity. Male peak activity occurred after midnight coinciding with female eclosion. Presence or absence of females did not affect when or how long males were active. Data on flight activity and reproductive behaviour are discussed in relation to the use of pheromones to protect maize.
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  • 39
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    Entomologia experimentalis et applicata 66 (1993), S. 171-177 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; egg parasites ; parasitoid quality ; mass rearing ; biological control ; factitious host
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    Topics: Biology
    Notes: Abstract The relationship between the index of female's size, hind tibia length (HTL), and selected fitness parameters used in quality assessment of mass-rearedTrichogramma spp. (Hymenoptera, Trichogrammatidae) was investigated. The studied fitness parameters were: the number of mature eggs present in the ovaries of females 0–2 hours, as well as 1, 2 and 3 days old, lifetime fecundity, fecundity during a 24 h period, longevity in the presence and absence of the factitious host (Ephestia kuehniella Zeller) and locomotor activity. The relationship between HTL and fitness parameters was analysed in 7 strains ofTrichogramma spp. (Trichogramma dendrolimi Matsumura,T. evanecens Westwood,T. maidis Pinturea et Voegelé andT. ostriniae Pang et Chen) using linear correlation. No significant relationship was found between HTL and egg complement, fecundity, longevity and locomotor activity. The results indicate that HTL used as an index of female's size is not suitable for quality assessment ofTrichogramma reared onE. kuehnieIla.
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  • 40
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    Entomologia experimentalis et applicata 70 (1994), S. 27-39 
    ISSN: 1570-7458
    Keywords: almond seed wasp ; Eurytoma amygdali ; diapause termination ; insect dormancy ; temperature ; prolonged diapause ; photoperiod ; Hymenoptera
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    Notes: Abstract Diapausing larvae ofEurytoma amygdali Enderlein (Hymenoptera, Eurytomidae) were collected in early August and late September. They were subjected to various photoperiod and temperature regimens for up to 20 weeks, then kept at L16:D8 and 19°C for another 14 to 26 weeks for diapause to be terminated and pupation to take place. Photoperiod did not affect diapause completion. It was confirmed that the two morphologically distinct diapause stages have different temperature requirements for their completion. The first diapause stage was completed synchronously at temperatures between 16 and 19°C. A higher temperature of 26°C delayed diapause development. The second stage required lower temperatures between 4 and 10°C. Spontaneous termination of dipause was observed at constant 19°C. When applied to the first diapause stage for 20 weeks, low temperatures made the larvae refractory to subsequent intermediate temperatures. The first stage was thus maintained until a higher temperature of 26°C made the larvae regain their ability to respond to the intermediate temperatures and complete this stage. Larvae grown in Retsou almonds had a higher diapause intensity than larvae grown in Truoito almonds. The results suggest that, in nature, the high temperatures of late summer and early autumn are likely to maintain the first diapause stage. Subsequently, the less warm temperatures of autumn allow the completion of the first stage by late autumn, and the low temperatures of late autumn and of winter allow the completion of the second diapause stage by mid winter.
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  • 41
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    Entomologia experimentalis et applicata 70 (1994), S. 83-90 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Symphyta ; Tenthredinidae ; Dineura virididorsata ; sawfly ; sex ratio ; oviposition behaviour ; mating behaviour
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    Notes: Abstract Sex ratios of the arrhenotokous sawflyDineura virididorsata Retz. (Hymenoptera: Tenthredinidae) are variable among populations in the field, but are biased in favour of females. We have concluded elsewhere that the sex ratios of this species cannot be satisfactorily explained by any general sex ratio model that is available. Here we present data on the different behavioural traits that are relevant to interpretation of the evolution of female-biased sex ratios under local mate competition. We report on oviposition behaviour, mating behaviour and the patterns of movement of ovipositing virgin and mated females. Our results show that adult emergence is synchronous and females will mate daily with different males (in the laboratory, at least). This would decrease the relatedness of offspring should it also take place in the field. In addition, ovipositing females (mated and virgin) leave their site of release in a relatively short time and deposit few eggs relative to their capabilities, so siblings are unlikely to be clumped. The time that virgins spend in deposition of an egg is not different from that spent by mated females, so there is no differential ‘investment’ in this regard. These behavioural observations agree with our previous conclusion that the preconditions of current sex ratio theories are not met byD. virididorsata.
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  • 42
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    Entomologia experimentalis et applicata 70 (1994), S. 121-128 
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Trichogrammatidae ; Trichogramma fuentesi ; couleur de l'hôte ; mutation récessive ; distribution ; influence de la température
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    Topics: Biology
    Description / Table of Contents: Abstract In Cuba, during its larval development inside its host egg,Trichogramma fuentesi turns its host egg either black or brown. Crossings carried out between the two forms ofT. fuentesi allowed to show that this character is determined by one locus with two alleles: Bh, dominant, colours the host black; and bh, recessive, colours the host brown. The bh allele is more frequent in the eastern region of Cuba which is also the warmest, than in the western region. We studied the evolution of frequencies of the two alleles in different experimental polymorphic populations at 23 °C and at 30 °C. In all tested conditions, bh was at a disadvantage by comparison with Bh, except at 30 °C when its initial frequency was high (90%). Thus, temperature alone should certainly not explain the maintenance of the observed polymorphism in Cuba.
    Notes: Résumé A Cuba, les oeufs hôtes parasités parTrichogramma fuentesi Torre (Hymenoptera: Trichogrammatidae) deviennent soit noirs, soit marrons. Une série de croisements entre Trichogrammes a permis de montrer que le déterminisme de ce caractère est sous la dépendance d'un locus portant deux allèles: Bh, dominant, confère une couleur noire à l'hôte; bh, récessif, confère une couleur marron. L'allèle bh étant plus fréquent dans la région orientale de Cuba, la plus chaude, nous avons suivi l'évolution des fréquences des deux allèles dans des populations expérimentales polymorphes placées à 23 °C et 30 °C. Dans toutes les conditions testées, bh a été désavantagé par rapport à Bh, sauf à 30 °C lorsque sa fréquence initiale était élevée (90%). La température n'explique donc certainement pas à elle seule le maintien du polymorphisme à Cuba.
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  • 43
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Tortricidae ; Choristoneura fumiferana ; juvenile hormone analog ; fenoxycarb ; postembryonic development
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    Entomologia experimentalis et applicata 64 (1992), S. 117-124 
    ISSN: 1570-7458
    Keywords: Learning ; specialist ; generalist ; parasitoid ; Leptopilina ; foraging behaviour ; Hymenoptera
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    Notes: Abstract Effects of learning in two microhabitat specialists, Leptopilina boulardia Barbotin et al. and L. fimbriata Kieffer were compared to previous and new results of learning in the microhabitat generalist L. heterotoma Thomson. Females were given one or more oviposition experiences on hosts in different types of substrate. In all species oviposition experience affected the choice for a substrate, although this effect of learning was considerably less in L. fimbriata compared to the other two species. Patch times, known to be highly determined by experience in the generalist L. heterotoma, were much less flexible in the specialists. L. boulardi and L. fimbriata have fixed patch times on their natural substrate and have variable patch times on other substrates only. In all three species one oviposition affected the choice for a substrate. Additional ovipositions showed no different effect. An accumulative effect of the number of ovipositions on patch times was found in L. heterotoma only. Retention of the learning effect was only studied in L. boulardi, and was shown to be similar to that reported for L. heterotoma, i.e. two to three days. Although learning was found in both the generalist and the specialist species studied, it seems to affect their foraging behaviour differently.
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  • 45
    ISSN: 1572-8889
    Keywords: leaf shelter-building ; silk ; Lepidoptera ; caterpillar ; leaf-roller ; leaf-tier ; leaf-folder
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    Notes: Abstract Leaf shelter-building caterpillars generate most of the force required to pull leaf surfaces together by stretching silk strands while spinning. Axially retractive forces produced by columns of stretched strands enabled caterpillars in our study to generate forces as great as 0.3 Newtons (i.e., a 30-g force). We found that caterpillar silk also contracts instantly when wetted, producing an additional, though smaller, axially retractive force. Contraction ratios (final length/ original length) of the wetted silk of 19 species ranged from 0.21 to 0.93 and were smallest among species that use their silk to make leaf shelters. Our study, the first to identify the specific sources of the energy harnessed by caterpillars to tie, roll, or fold leaves, indicates that silk properties and caterpillar behavior have coevolved to facilitate the leaf shelter-building process.
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  • 46
    ISSN: 1572-8889
    Keywords: Seed chalcid ; Bruchophagus spp. ; Hymenoptera ; Eurytomidae ; Chalcidae ; olfactory behavior ; polarization vision ; insect behavior
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    Notes: Abstract When the alfalfa [Bruchophagus roddi (Gussakovsky)], clover [Bruchophagus gibbus (Boheman)], and trefoil seed chaldds (TSC) [Bruchophagus platypterus (Walker)] were exposed to yellow, white, green, and purple painted polyethylene vials perforated by four small holes, only the latter species had a color preference, and that was for yellow, the color of its host flower. When TSC were exposed to green and yellow targets 5 h after sunrise, they preferred yellow targets but not 1 h after sunrise. The possibility of a circadian response was eliminated because different sequences of light-dark regimes prior to the test did not change the results. When TSC were exposed only to yellow targets, half of which had trefoil flowers hidden within, females preferred targets with flowers. When an identical test was conducted but with green instead of yellow targets, the preference for targets with flowers disappeared. In a four-choice test, TSC preferred yellow targets with or without flowers to green targets with or without flowers. Thus, TSC displayed an olfactory response only when the color yellow was present. In unfiltered skylight females preferred baited targets when the test began 3 h before or 1 h after solar noon but not 4 h before or 2 h after solar noon. Chalcids did display an olfactory preference 4 h before solar noon when a Polaroid filter was used to filter skylight and provide an east-west but not a north-south E-vector. When Helmholtz coils were used to apply a magnetic field that canceled or changed the direction of the earth's magnetic field, olfactory preference disappeared because the applied magnetic field changed TSC perception of the E-vector. In effect, TSC must perceive yellow in the presence of an east-west E-vector to display an olfactory preference to a choice of odors. We believe this is the first report that the E-vector of celestial light can influence olfactory and visual behavior of an insect.
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  • 47
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Leptopilina ; Drosophila ; semiochemicals ; kairomones ; parasitoid ; generalist ; specialist ; foraging behavior
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    Notes: Abstract Foraging parasitoids are thought to need more specific information than generalists on the presence, identity, availability, and suitability of their insect host species. In the present paper, we compare responses to host kairomones by two phylogenetically related parasitoid species that attack Drosophilidae and that differ in the width of their host range. As predicted, the behavioral response of the parasitoids to host kairomones reflected their difference in host range. The response of the specialist parasitoid Leptopilina boulardiwas restricted to contact kairomones from its natural hosts and one closely related species. In contrast, the generalist parasitoid Leptopilina heterotomaresponded to contact kairomones of a variety of Drosophilidae species.
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  • 48
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    Journal of insect behavior 6 (1993), S. 737-750 
    ISSN: 1572-8889
    Keywords: sex pheromone ; vibrational communication ; courtship sequence ; Hymenoptera ; Braconidae ; Cotesia rubecula
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    Topics: Biology
    Notes: Abstract The courtship behavior of the parasitic wasp Cotesia rubeculawas studied in a flight tunnel using standard quantitative ethological techniques. Emission of a female sex pheromone induces searching and signaling behavior in males. Males combine wing-fanning, which produces low-frequency airborne sound, with “pulsing” behavior, which transmits a vibrational signal through the substrate to the female and induces her receptivity. Female receptivity is indicated by a stereotyped antennal position, which may provide a visual or tactile signal to courting males. Comparison of successful and unsuccessful courtships indicated that courtship success was dependent primarily on the effective production or reception of the male pulse signal. Overall, the sequence of courtship behavior was similar to that reported for other parasitic wasps.
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  • 49
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    Journal of insect behavior 6 (1993), S. 771-781 
    ISSN: 1572-8889
    Keywords: foraging behavior ; caterpillar-feeding damage ; paper wasps ; Lepidoptera
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    Topics: Biology
    Notes: Abstract Experiments were performed to determine the effect of caterpillar feeding damage on wasp foraging behavior and to determine the relative importance of visual and olfactory plant cues for foraging wasps. In an experiment using caterpillar-damaged leaves, wasps took significantly more larvae from the previously damaged plants compared to the controls in the experiments with tobacco plants, but wasps did not distinguish between damaged and control plants in the experiments with tomato plants. Another experiment indicated that wasps use a combination of visual and olfactory cues of plant damage in their search for prey rather than just visual or olfactory cues alone. Furthermore, these results suggest that leaf shape may affect wasp detection of caterpillar feeding damage and thus detection of prey.
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  • 50
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    Journal of insect behavior 3 (1990), S. 277-287 
    ISSN: 1572-8889
    Keywords: parasitoid behavior ; heritable traits ; Microplitis croceipes ; Hymenoptera ; Braconidae ; allelochemical ; flight response ; host location
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    Notes: Abstract The heritable nature of differential responses by Microplitis croceipes(Cresson) (Hymenoptera: Braconidae) to airborne allelochemicals was investigated. Four isofemale lines were tested for three generations in a flight tunnel. Flight response was found to be strongly dependent on the familial origin, with two highly responsive lines being clearly differentiated from two less responsive ones. Each isofemale line could also be recognized by typical behaviors that suggested that M. croceipesfemales may inherit independent characters of sensory acuity to plant and to host chemicals and of learning ability.
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  • 51
    ISSN: 1572-8889
    Keywords: postemergence learning ; cross-induction ; foraging behavior ; Cotesia congregata (Say) ; Braconidae ; Hymenoptera
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    Notes: Abstract Postemergence experience with one of six plant species, in the presence of the host larva, modified the searching response of reproductively mature females of Cotesia congregata(Say) to these plants in at least one of three ways: (1) an increased response to the plant experienced at emergence, (2) an increased response to other plants, or (3) an inhibited response to other plants. Landing and searching responses were differentially affected by postemergence experience. For example, postemergence experience with tobacco (a common plant) in the presence of the host larva induced a landing preference for this plant over parsley (a novel plant) but did not affect searching responses to either plant, whereas experience with parsley and the host larva induced an increased searching response to parsley but a landing preference for tobacco. Differential effects of postemergence experience may reflect the type of stimuli involved in searching or landing and may have adaptive significance.
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  • 52
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    Journal of insect behavior 7 (1994), S. 605-632 
    ISSN: 1572-8889
    Keywords: Heliothis ; Lepidoptera ; Noctuidae ; pheromone ; visual feedback
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    Topics: Biology
    Notes: Abstract MaleHeliothis virescens (F.) (Lepidoptera: Noctuidae) were made to fly into a uniformly white and translucent tube within a large wind tunnel while responding to sex pheromone. Different visual patterns placed within the tube greatly affected the ability of the male moths to maintain upwind progress or remain oriented to the wind while in contact with the plume. Over 89% of males attempting to fly through a blank tube, lacking visual patterns, became disoriented, the males gaining or losing altitude and repeatedly hitting the sides of the tube. Patterns of 20–40 dots placed on the sides of the tube at or slightly above plume level resulted in high levels of sustained upwind flight (47–74%) relative to patterns placed directly below (30–40%), directly above (35%), or slightly below the level of the flight path (26–44%). Optimal upwind progression in pheromone-responding males occurred when image motion could be resolved both transversely (T), orthogonally to the longitudinal axis of the body relative to the horizontal plane of the environment, and longitudinally (L), along the body axis. Even very sparse patterns (single rows of dots) could elicit high levels of sustained upwind flight (53–63%) when positioned within the tube such that the males' movements would create both L and T image motion. However, successful negotiation of the tube was also unexpectedly facilitated by patterns apparently providing no horizontal transverse component for flying males but providing longitudinal flow while centering the moth in the plume through a symmetrical left-right input (4–40%).
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  • 53
    ISSN: 1572-8889
    Keywords: parasitoid ; foraging behavior ; Hymenoptera ; Cotesia ; Lepidoptera ; Pieris ; host location ; solitary ; gregarious ; specialist ; generalist
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    Notes: Abstract In the present study we apply a comparative approach, in combination with experimentation, to study behavior of two parasitoid species that attack caterpillar hosts with different feeding strategies (gregarious or solitary). In a semifield setup, consisting of clean cabbage plants and plants infested with one of two host species, the foraging behavior of the specialistCotesia rubecula, on obligate parasitoid of solitarily feedingPieris rapae larvae, was compared to that of the generalistCotesia glomerata, a polyphagous parasitoid of several Pieridae species (mainly the gregariously feedingPieris brassicae).Cotesia glomerata displayed equal propensity to search for and parasitize larvae of both host species. AlthoughC. glomerata exhibited a relatively plastic foraging behavior in that it searched differently under different host distribution conditions, its behavior seems more adapted to search for gregariously feeding hosts. Females exhibited a clear “area-restricted” search pattern and were more successful in finding the gregariously feeding caterpillars.Cotesia rubecula showed a higher propensity to search forP. rapae than forP. brassicae, i.e., females left the foraging setup significantly earlier when their natural hostP. rapae was not present.C. rubecula showed a more fixed foraging behavior, which seems adapted to foraging for solitarily feeding host larvae. In a setup with onlyP. rapae larvae, the foraging strategies of the two parasitoid species were quite similar. In a choice situationC. glomerata did not show a preference for one of the host species, whileCotesia rubecula showed a clear preference for its natural host species. The latter was shown by several behavioral parameters such as the number of first landings, allocation of search time, and percentage parasitization.
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    Journal of insect behavior 7 (1994), S. 885-889 
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    Keywords: Lepidoptera ; Noctuidae ; Mamestra brassicae ; male scents ; hair-pencils ; courtship
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    Journal of insect behavior 3 (1990), S. 85-104 
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Vespidae ; Belonogaster petiolata ; rubbing behavior ; sternal gland ; ant predation ; defensive allomone
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    Notes: Abstract Females of the social wasp, Belonogaster petiolata,rub the secretion of van der Vecht's gland, located on their terminal gastral sternite, onto the nest pedicel. In bioassays, the secretion was repellent to two species of ants, while shortchain acids were effective releasers of rubbing behavior. Rubbing was associated with pedicel enlargement and departure from the nest in preemergence colonies. Its frequency was high where wasps were often exposed to ants and low where ants were rare or absent. Rubbing also decreased significantly from the pre-to the postemergence stage of the colony cycle. In both stages, subordinate foundresses rubbed more often than queens or workers. These observations support the hypothesis that rubbing behavior and the secretion of van der Vecht's gland function in chemical defense of the nest against ant predation. The general morphology of the gland in B. petiolataresembles that of the four other independent-founding polistine wasp genera.
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  • 56
    ISSN: 1572-8889
    Keywords: cotton bollworm ; Heliothis armigera ; Lepidoptera ; Noctuidae ; sex pheromone ; flight tunnel ; male behavior
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    Topics: Biology
    Notes: Abstract Six compounds were identified from gland extracts of the cotton bollworm, Heliothis armigera(Hubner): (Z)-11-hexadecenal (Z11-16:Ald), (Z)-9-hexa-decenal (Z9-16:Ald), hexadecanal, (Z)-11-hexadecenol (Z11-16:OH), (Z)-7-hexadecenal (Z7-16:Ald), and (Z)-9-tetradecenal (Z9-14:Ald). Each of the compounds that were identified was examined for its ability to elicit sexual responses from male moths in a flight tunnel. Males flew upwind to Z11-16:Ald alone, but greater levels of copulatory responses were evoked with the addition of 2.5% Z9-16:Ald to the Z11-16:Ald. Addition of hexadecanal to the binary mixture had no effect in raising the behavioral response of the males in the flight tunnel. The effect of Z7-16:Ald on male flight depended on the loading. The addition of 1% of this component to 2 mg of the binary mixture reduced levels of copulatory response, but the same addition (1 %) to 10 μg of the binary mixture increased copulatory response. The addition of 79-14:Ald or Z11-16:OH to the binary mixture reduced behavioral responses of males. High loadings of the binary mixture (200–2000 μg) were better than a low loading (10 μg) in eliciting response of males.
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  • 57
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    Journal of insect behavior 3 (1990), S. 241-250 
    ISSN: 1572-8889
    Keywords: antipredator behavior ; prey caching ; Ammophila ; Formica ; foraging behavior ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Many solitary ground-nesting wasps in the families Pompilidae and Sphecidae excavate nests after capturing prey for provisions. These wasps generally cache their immobilized prey temporarily during nest excavation, frequently by suspending the prey in a plant (”aerial caching”). Here I test the hypothesis that aerial caching by Ammophila spp. wasps (Sphecidae) functions to reduce prey theft by generalist predators, Formica spp. ants. Foraging ants removed baits placed on the ground more rapidly than baits suspended in plants; mean half-lives for ground and aerial baits were 14.5 and 145.7 min, respectively (mean values for experiments 1–3). Ant foraging activity decreased during the midday. Ant interference with nesting activities of Ammophila spp. also decreased during the midday, paralleling observed fluctuations in ant foraging activity.
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  • 58
    ISSN: 1572-8889
    Keywords: host selection ; experience ; learning ; extinction ; reinforcement ; parasitoids ; Drosophila ; Leptopilina heterotoma ; Hymenoptera ; Eucoilidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The host-foraging behavior of female entomophagous parasitoids is commonly modified by positive associative learning. Typically, a rewarding experience (e.g., successful oviposition in a host) increases a female's foraging effort in a host microhabitat of the type associated with that experience. Less well understood are the effects of unrewarding experiences (i.e., unsuccessful foraging). The influence of unrewarding experience on microhabitat choice and residence time within a microhabitat was examined for the eucoilid parasitoid,Leptopilina heterotoma, in laboratory and greenhouse assays. As determined previously, females which oviposited successfully in either of two microhabitat types (fermenting apple or decaying mushroom) strongly preferred to forage subsequently on that microhabitat type. However, failure to find hosts in the formerly rewarding microhabitat caused females to reverse their preference in favor of a novel microhabitat type. The effect, though striking, was transient: within 1–2 h, the original learned preference was nearly fully restored. Similar effects of unrewarding experiences were observed with respect to the length of time spent foraging in a microhabitat. As determined previously, oviposition experience in a particular microhabitat type increased the time spent foraging in a patch of that microhabitat type. However, failure to find hosts in the patch caused the time a wasp spent in the next unoccupied patch of that type to decrease to almost nothing. In addition, there was a tendency for an unrewarding experience on a formerly rewarding microhabitat type to extend the time spent in a patch of a novel type. The function of the observed effects of unrewarding experiences is discussed.
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  • 59
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    Journal of insect behavior 3 (1990), S. 359-379 
    ISSN: 1572-8889
    Keywords: ant ; aggression ; kin discrimination ; Rhytidoponera confusa ; Hymenoptera ; Formicidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Significant variation in aggressiveness and kin discrimination ability occurs between different laboratory colonies of the ant Rhytidoponera confusa.Different colonies show consistently high (or low) levels of aggression toward nonnestmates over 4–19 weeks. Earlier studies excluded colony size and the natural presence or absence of the queen in colonies and differences in hunger as possible sources of variation. The present study excluded the number of larvae in colonies and the time of the light period of the light cycle when recognition tests were carried out. Highly significant variation occurs between the kin discrimination ability of individual workers in any particular colony. Approximately 28% of the workers in colonies of R. confusashowed very poor kin discrimination. Much of the colony's kin discrimination is carried out by a small number of highly aggressive workers.
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  • 60
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    Journal of insect behavior 4 (1991), S. 743-750 
    ISSN: 1572-8889
    Keywords: Leptopilina boulardi ; Hymenoptera ; Eucoilidae ; parasitoid ; olfaction ; learning ; olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied odor learning in Leptopilina boulardi,a specialist larval parasitoid of Drosophila melanogaster.The behavioral responses of differently experienced females to an artificial odor (Must de Cartier, Paris) were analyzed using a fourarmed airflow olfactometer. The responses of females with an oviposition experience in the presence of the perfume were compared with those of four control groups. As controls we used naive females, females with an oviposition experience in the absence of odor, females which had been previously exposed to perfume but without an oviposition experience, and females with an oviposition experience which also had been exposed to perfume but not at the same time. The results demonstrate that a specialist such as L. boulardican learn very well to respond to an artificial odor by associating this odor with a reward, i.e., an oviposition. The four control groups responded more or less in a similar way.
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  • 61
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Braconidae ; Dacnusa sibirica ; Diptera ; Agromyzidae ; Liriomyza bryoniae ; foraging behavior ; volatile infochemicals ; wind tunnel ; anemotaxis ; learning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous investigations suggested that the leafminer parasitoid Dacnusa sibirica Telenga does not use a volatile hostrelated infochemical in foraging for hosts. Parasitoids landed with equal frequencies on an uninfested tomato plant and on a tomato plant infested with larvae of the leafminer Liriomyza bryoniae (Kalt.) (Hendrikse et al., 1980). In contrast, we found that volatile infochemicals emitted by uninfested and leafminer-infested tomato plants differently affected the parasitoid 's foraging behavior in a windtunnel. This was obvious from the proportion of wasps flying upwind but not from the proportion of wasps landing on the leaves. Latency time on an uninfested tomato leaflet and proportion of latency time devoted to preflight antennal behavior were influenced by the presence of upwind infested or uninfested tomato leaves. However, these parameters were not affected by odors in the absence of visual plant stimuli. Our data provide a new view on foraging behavior of Dacnusa sibirica.
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  • 62
    ISSN: 1572-8889
    Keywords: Heliothis virescens ; Noctuidae ; Lepidoptera ; upwind flight ; sex pheromone ; filaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aspects of the intermittent fine structure of an odor plume were mimicked and experimentally modified in the wind tunnel using an air-pulsing device. Filaments of a behaviorally active blend of six sex-pheromone components created by the device in a temporally regular fashion elicited sustained upwind flight and source location in male Heliothis virescens.Males did not exhibit sustained upwind flight in significant numbers until a frequency of 4 filaments/s was delivered, at a loading of 1 μg of the major component, Z11-16: Ald, with the other components loaded at their appropriate ratios. A loading of 10 μg Z11-16: Ald was found to be optimal at this filament delivery rate. Electroantennogram recordings to different filament delivery rates of the complete blend indicated that a stationary male antenna can respond to the pulse rates used in this study. Importantly, when a main component necessary for upwind flight, Z9-14:Ald, was isolated into its own filaments and pulsed alternately against filaments of the five other components (including the other component essential for upwind flight, Z11-16: Ald), upwind flight to the source was significantly reduced (9%) compared to upwind flight and source location in response to filaments composed of the entire blend (30%), indicating that the complete pheromone blend must arrive on the antenna simultaneously for optimal evocation of sustained upwind progress. Neurophysiological evidence from other studies suggests that higher-order interneurons whose phasic response is enhanced when the entire blend is presented simultaneously may be of importance in explaining this behavioral difference stemming from synchronous vsasynchronous arrival of the components.
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  • 63
    ISSN: 1572-8889
    Keywords: sex pheromone ; landing behavior ; visual cues ; Epiphyas postvittana ; Lepidoptera ; Tortricidae
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    Topics: Biology
    Notes: Abstract The effects of changes in various visual and olfactory properties of a white card surface on the landing position of male Epiphyas postvittanaexhibiting pheromone-mediated flight were studied in a wind tunnel. Males landed predominantly at the most downwind position of a surface in line with the pheromone source, regardless of the strength of the source. The position on the surface that males landed was strongly influenced by visual factors. The landing position of males appeared to be influenced by visual cues along all three axes of the surface. Decreases in either the dimension horizontally perpendicular to the wind direction or the vertical dimension resulted in greater numbers of males landing farther upwind on the surface than the downwind edge. Visual changes in the axis along the wind direction also affected the position at which males landed. For example, when presented with two white card surfaces with a 4- cm gap between them, males tended to land on the downwind edge of the upwind surface (on which the source was located). When the gap was bridged with clear Mylar, the landing pattern was significantly different, with the greater proportion of males landing on the downwind surface. However, when Mylar was placed on the plexiglass floor of the tunnel (in addition to bridging the gap), the landing pattern on the surface was not significantly different from that on the two surfaces without the Mylar bridge. It is suggested that during the prelanding and landing phases of pheromone-mediated flight, male moths orient to visual features of the surface containing the pheromone source rather than to visual features of the source (conspecific female moth) itself.
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  • 64
    ISSN: 1572-8889
    Keywords: Phoridae ; Diptera ; Formicidae ; Hymenoptera ; host ; parasitoid ; behavior ; Atta ; Neodohrniphora
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    Topics: Biology
    Notes: Abstract This study examines the oviposition behavior of the phorid parasitoid Neodohrniphora curvinervisand the antiparasitoid defense behavior of its leafcutting ant host Atta cephalotes. N. curvinervisfemales are diurnal sit- and- wait parasitoids that attack only outbound foragers of head width 1.6 mm or greater. Females deposit a single egg through the foramen magnum of each host successfully parasitized. Pursuit of hosts is usually initiated when an outbound forager of acceptable size passes by a parasitoid perch site. Individual foragers defend themselves against pursuing parasitoids by outrunning them along the foraging trail or by standing their ground and fending them off with their legs,antennae, and mandibles. At the colony level, susceptible foragers are protected against parasitism by a shift in the forager size distribution toward smaller unsusceptible sizes during the day when parasitoids are active and toward larger sizes at night when parasitoids are inactive. The frequency of parasitism of susceptible foragers was 15%, which is more than five times the frequency found in another system involving the phorid parasitoid Apocephalus attophilusand the leafcutting ant host Atta colombica.We offer several possible explanations for such differences in the frequency of parasitism and also examine reasons for the high incidence of superparasitism (19%) observed in the system studied.
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  • 65
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Vespidae ; Vespula spp. ; foraging behavior ; chemoorientation ; social facilitation ; local enhancement ; spatial dispersion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A series of experiments on the discovery of meat bait by scavenging workers ofV. germanica andV. maculifrons showed that workers oriented to meats by visual cues and olfactory cues. Scavening workers ofV. germanica andV. maculifrons responded positively to the sight of conspecifics at meat baits; i.e., meat with (confined) wasps received more visits than meat without wasps. This attraction to conspecific workers on meat baits provides evidence of local enhancement, in that the presence of conspecifics at meat bait directs other wasps to a particular spatial locality. Local enhancement by yellowjackets foraging for meat may contribute to the clumped distribution of worker populations noted in studies of workers captured in meat-baited traps. We hypothesize that local enhancement of foraging is a ubiquitous behavior in species of theV. vulgaris species group and may be one attribute explaining their ecological success.
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  • 66
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    Journal of insect behavior 4 (1991), S. 727-742 
    ISSN: 1572-8889
    Keywords: postemergence learning ; early-adult experience ; Cotesia congregata (Say) ; Braconidae ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Exposing newly emerged females of Cotesia congregata(Say) to wild cherry, an inherently unattractive plant, and their host larvae at 0–4 h after adult emergence induced a positive searching response to wild cherry and an inhibited response to cabbage, an attractive plant. Inherent responses were not affected when females were exposed to their hosts at 0–12 h and to cherry at 8–12 h after emergence. The induced response to cherry was constant until its disappearance at 6–7 days;inhibition of the response to cabbage was released at 4–5 days after emergence. Postemergence exposure to cherry and parasitoid cocoons induced similar but weaker searching responses. Induced searching responses exhibit features of associative learning and receptor modification. In addition to its presumed role in foraging, postemergence experience with plants may encourage assortative mating of C. congregatawithin suitable host habitats and, thus, facilitate local adaptations to specific plants.
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  • 67
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Braconidae ; Opius dissitus ; Diptera ; Agromyzidae ; Liriomyza sativae ; semiochemical ; volatile ; foraging behavior ; adult experience ; learning
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract Oviposition-experienced females of Opius dissitus Muesebeck, a braconid parasitoid of Liriomyza sativaeBlanchard, preferentially landed on leafminer-infested rather than uninfested lima bean (Phaseolus lunatus L.) plants in a flight tunnel assay. Both naive and oviposition-experiencedparasitoids responded strongly to odors of infested lima bean plants in a four-arm olfactometer in comparison with odors of uninfested plants, suggesting that volatile semiochemicals are used in host location. Parasitoids with an oviposition experience on lima bean (“lima-experienced”) spent significantly more time in the infested odor than naive individuals, however, eggplant-experienced wasps did not spend significantly more time in the infested odor field than naive wasps. When parasitoids reared on leafminers in lima bean were provided a choice between the odor of infested lima bean and the odor of infested eggplant or cotton, naive and lima-experienced wasps preferred infested lima odor. An oviposition experience on the other plant species resulted in a dramatic shift in preference. It was concluded that the experience effect was due, at least in part, to associative learning, as has been reported for other parasitoids. The parasitoids may perceive unconditioned stimuli during host contact and oviposition on an infested leaf and may associate those stimuli with volatile semiochemicals emanating from the leaf or host. Subsequently, the volatiles associated with the presence of hosts are used in directing the search for hosts.
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  • 68
    ISSN: 1572-8889
    Keywords: Tanacetum vulgare ; Tansy ; Lobesia botrana ; European grapevine moth ; Asteracea ; Lepidoptera ; Tortricidae ; oviposition ; behavior ; nonhost plant ; semiochemicals ; plant odor ; olfaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Females ofLobesia botrana Den. et Schiff. (Lepidoptera Tortricidae) are attracted in natural conditions by volatiles released by a nonhost plant: tansy (Tanacetum vulgare L.; Asteracea). We have shown that both tansy flowers and their odor inhibit oviposition behavior and mating behavior and reduce adult longevity. The mean number of eggs laid per female isolated with tansy flowers was reduced by up to 50% every 2 days during the 6 days of exposure. This reduction was maintained after the tansy was removed. In the presence of tansy essential oil, the egg-laying reduction ranged from about 30 to 80% according to the odor concentration. The number of spermatophores found in females isolated with tansy flowers was also reduced twofold compared to the control treatment, indicating that the presence of tansy reduced mating activity. This mating activity is strongly reduced, by two-thirds, when adults face the highest dose of essential oil compared to controls. The number of eggs laid by the controls cannot be explained by the number of spermatophores. Therefore, the reduction in oviposition has been attributed to the presence of tansy flowers or to the tansy odor. Tansy flowers and tansy odor increased male mortality during the exposure (10% in the control, 50% in the tansy treatment, and up to 98% in the odor treatment). The highest rates of male mortality occurred during the 4- to 6-day period of exposure to flowers or odor. Repellence resulting in sustained locomotor activity is a possible cause of such a mortality. Female mortality was increased only in response to the highest dose of odor. This increase might be due to egg retention, and not directly to a plant effect. We discuss the effects of tansy flower odor on different patterns relative to the reproductive behavior ofL. botrana and, especially, on oviposition behavior in the ecological context of plant selection and polyphagy.
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  • 69
    ISSN: 1572-8889
    Keywords: Hymenoptera ; Braconidae ; Microplitis croceipes ; cotton ; cowpea ; parasitoid ; host location ; kairomones ; olfaction ; induced plant responses ; learning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A study was conducted to determine the primary source of volatile cues within the plant-host complex used by hostseeking freeflying female Microplitis cro-ceipesCresson in flight tunnel bioassays. In single-source and two-choice tests, using wasps given an oviposition experience on either cotton (Gossypium hirsutum)or cowpea (Vigna unguiculata)seedlings damaged by corn earworm (CEW; Helicoverpa zeaBoddie), the damaged seedlings were significantly more attractive than the CEW frass, which was in turn more attractive than the larvae themselves. In a series of two-choice wind-tunnel tests, the discriminatory ability of the wasps was examined, following various oviposition experiences. Significantly more wasps flew to plants with “old” damage than to plants with “fresh” damage, regardless of whether they had experience on fresh or old damage. In a comparison of plant species, wasps with only one experience on either hostdamaged cotton or host-damaged cowpea were unable to distinguish between them, and showed no preference for either plant, whereas wasps with multiple experiences on a particular plant preferentially flew to that plant in the choice test. In comparing hosts with nonhosts, wasps successfully learned to distinguish CEW from beet armyworm (BAW; Spodoptera exigua)on cotton but were unable to distinguish CEW from either BAW or cabbage looper (Trichoplusia ni)on cowpea. The results show the important role played by plant volatiles in the location of hosts by M. croceipesand indicate the wasps’ limitations in discriminating among the various odors. The ecological advantages and disadvantages of this behavior are discussed.
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  • 70
    ISSN: 1572-8889
    Keywords: brood ; pheromone ; slavemaking ants ; Polyergus breviceps ; Formica occulta ; Hymenoptera ; Formicidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freeliving workers of Formica occulta, an ant species enslaved by the obligatory slavemaking ant Polyergus breviceps, retrieve and nurse Polyergus pupaejust as well as conspecific pupae in a choice test. No such attraction was found toward pupae of the facultative slavemaker; Formica wheeleri,which also enslaves F. occulta. Formica neogagates,a sympatric species which is not parasitized by either slavemaker, preferentially retrieves and tends conspecific brood over that of Polyergusand F. wheeleri.It is proposed that brood of obligatory slavemaking species must possess an attractive pheromone for slavemaker colony foundation to be successful, since slavemaker brood must be nursed by adult slave workers with no prior exposure to slavemaker brood. An attractive pheromone is not necessary in the brood of facultative slavemakers, since this brood is cared for by newly eclosed slave workers who imprint on the slavemaker brood.
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  • 71
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    Entomologia experimentalis et applicata 60 (1991), S. 219-223 
    ISSN: 1570-7458
    Keywords: Spilonota ocellana D. & S. ; Spilonota laricana Hein. ; Lepidoptera ; Tortricidae ; sex pheromone ; (Z)-8-tetradecenyl acetate ; (Z)-8-tetradecen-1-ol ; sibling species ; reproductive isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sex pheromones of Spilonota ocellana D. & S. and Spilonota laricana Hein. (Lepidoptera: Tortricidae) were identified by chemical analysis and field trapping. Female moths of the two species produce (Z)-8-tetradecenyl acetate, (Z)-8-tetradecen-1-ol and dodecyl acetate in almost the same proportions (98:1:1 and 97:3:1). Males of both species were best attracted to a blend of 10:1 to 1:1 Z8-14Ac:Z8-14OH. This indicates that mating barriers other than sex pheromones exist between sympatric populations.
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  • 72
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    Entomologia experimentalis et applicata 54 (1990), S. 173-180 
    ISSN: 1570-7458
    Keywords: Encapsulation ; evolutionary relationships ; host suitability ; parasitization ; parasitoid complexes ; Diadegma armillata ; Hymenoptera ; Ichneumonidae ; Lepidoptera ; Yponomeutidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'étude a porté sur la valeur de 8 représentants européens du genre Yponomeuta (Lep., Yponomeutidae) comme hôtes pour Diadegma armillata (Hym., Ichneumonidae). La présence, l'état du parasitoïde, le nombre de chenilles contenant un hyménoptère et la mortalité des chenilles on été examinés par dissection et par élevage des chenilles attaquées en conditions contrôlées. Pour examiner si la mortalité des chenilles saines et parasitées diffèrent, des chenilles non contaminées par l'ichneumonide ont été utilisées comme témoins. De plus, des chenilles provenant de différentes parties des Pays-Bas et d'Allemagne ont été disséquées pour connaître leur taux de parasitisme par D. armillata. La valeur des diverses espèces diffère considérablement. Les dissections montrent que cela provient de différentes aptitudes à l'encapsulation des œufs du parasite. La comparaison des taux observés par la dissection des chenilles des différentes parties des Pays-Bas et d'Allemagne montre une surprenante uniformité pour les populations d'origines géographiques différentes. Les observations sur l'encapsulation par les différentes espèces d'yponomeutes correspondent assez bien aux différences observées parmi les divers complexes parasitaires dans lesquels D. armillata intervient. Certains éléments montrent cependant que le taux d'attaques victorieuses (sans tenir compte d'une éventuelle encapsulation ultérieure) contribue aussi aux différences observées entre les complexes parasitaires. Le classement des espèces d'yponomeutes en 3 catégories, d'après leur valeur comme hôte, montre un remarquable parallélisme avec les relations phylogéniques mises en évidence par analyse des allozymes: les espèces présentant une forte proportion d'encapsulation sont celles qui ont divergé précocement au cours de l'évolution du genre, tandis que les espèces ayant divergé le plus récemment présentent un pourcentage intermédiaire ou sont incapables d'encapsuler les œufs de D. armillata.
    Notes: Abstract The suitability as a host of Diadegma armillata (Gravenhorst) (Hymenoptera, Ichneumonidae) was determined for eight West-European representatives of the genus Yponomeuta Latreille (Lepidoptera, Yponomeutidae) by dissecting and rearing parasitized larvae under controlled conditions. The suitability of the various species differed considerably, and dissection showed that this was mainly due to the ability of the host species to encapsulate the parasitoid eggs. Encapsulation by Yponomeuta-species corresponded fairly well to the differences between the parasitoid complexes concerning D. armillata. Classifying the Yponomeuta-species into three categories according to their suitability, showed a remarkable parallelism with the phylogenetic relationships as determined by allozyme comparison: species showing high encapsulation rates are those that have diverged early in the evolution of the genus, whereas the more recently evolved species showed an intermediate percentage or were not able to encapsulate eggs of D. armillata.
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    Entomologia experimentalis et applicata 63 (1992), S. 229-236 
    ISSN: 1570-7458
    Keywords: Azinphosmethyl ; time response tests ; resistance ; Trioxys pallidus ; biological control ; genetic improvement ; Hymenoptera ; Aphidiidae ; gene amplification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Homogeneity in azinphosmethyl resistance was assessed in males of a laboratory-selected (Select-17) and susceptible (Yolo) colony of Trioxys pallidus Haliday (Hymenoptera: Aphidiidae) using a time response assay. No evidence of heterogeneity within the two colonies was found. Reciprocal crosses between the Yolo and the Select-19 (the Select-17 colony following two additional selections) colonies resulted in F1 females that exhibited a semidominant response to azinphosmethyl with a dominance value (D) of 0.32, as well as no evidence of maternal effects or sex linkage. Responses of F2 progeny to azinphosmethyl suggest that more than one gene may be involved because no inflection was observed in the time response lines of F2 males. Additional research is required to fully elucidate the mode of inheritance.
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  • 74
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    Entomologia experimentalis et applicata 55 (1990), S. 47-57 
    ISSN: 1570-7458
    Keywords: Campoletis sonorensis ; parasitoid ; Hymenoptera ; Ichneumonidae ; Heliothis virescens ; cotton ; potential host community location ; host location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les comportements d'évaluation de l'effectif d'hôtes potentiels et de la position des hôtes par C. sonorensis (Hyméno.: Iccheumonidae) ont été quantifiés pour déterminer les séquences significatives des événements comportementaux. La localisation de la colonie potentielle d'hôtes est apparue comme une séquence régulière des événements comportementaux. Une fois que le parasitoïde a localisé une colonie potentielle, on a constaté que la recherche au hasard des hôtes se poursuit jusqu'à ce qu'il ait la démonstration qu'il s'agit d'une plante attaquée. La localisation par le parasitoïde d'un hôte certain a consitué une autre séquence régulière des événements comportementaux terminant la localisation de l'hôte. L'influence de pieds de coton intacts, de pieds abîmés mécaniquement et de pieds occupés par des chenilles du 3ème stade de l'hôte et de plantes dont les chenilles ont été retirées juste avant l'expérience a été déterminée en modifiant la composition du complexe hôte/plante. Des femelles naïves de C. sonorensis ont montré en présence de pieds de coton intacts apparemment toutes les séquences comportementales de vol impliquées dans la localisation d'une colonie potentielle d'hôtes. Une fois que le parasitoïde a atteint la colonie potentielle d'hôtes, la présence de dégâts de l'hôte n'a pas modifié le temps passé sur la plante, mais a modifié le temps consacré à la prospection.
    Notes: Abstract Wind tunnel flight behavior of inexperienced female Campoletis sonorensis (Cameron) (Hymenoptera; Ichneumonidae) in response to its larval host Heliothis virescens (F.) (Lepidoptera: Noctuidae) feeding on the host plant cotton (Gossypium hirsutum L.) is described. The flight behavioral sequence was determined by quantification of frequencies of observed behaviors and probabilities of first-order behavioral transitions. Comparison of inexperienced C. sonorensis flights to undamaged and damaged cotton indicated that stimuli from undamaged plants alone are adequate to elicit the complete flight behavioral sequence observed in response to H. virescens feeding on cotton. Parasitoid foraging behavior was also analyzed after landing on the stimulus. This behavior appeared to be random in its initial stages, but became sequential after location of evidence of a host. Analysis of foraging on undamaged and 3 treatments of damaged cotton resulted in the determination that parasitoids tend to remain on damaged plants longer than undamaged plants although no significant difference was detected. C. sonorensis spent a greater percentage of their time foraging on host damaged plants than on undamaged plants.
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  • 75
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    Entomologia experimentalis et applicata 67 (1993), S. 199-207 
    ISSN: 1570-7458
    Keywords: Helicoverpa zea ; Lepidoptera ; Noctuidae ; precocene II ; growth inhibition ; excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Newly-ecdysed last instar larvae ofH. zea grouped into 100-, 200-, 300-, or 400-mg categories were fed diet containing precocene II or given precocene II topically on the abdomen. The time for larvae to reach a maximal weight, time to pupation, growth rate, and the amount of precocene II excreted were calculated. Younger larvae of lower weights, which were fed or topically treated with precocene II required more time to reach their maximal weight, had a lower maximal weight, a lower growth rate, and required more time to pupate than control larvae. Older larvae represented by the largest weight category were less sensitive to precocene II, had a shorter delay in reaching maximal weight, and a shorter delay in the time to pupation than control larvae; larvae in the largest weight category that were fed precocene II also had smaller decreases in the growth rate. Growth rate declines for larvae given topical doses of precocene II, however, were largest for the oldest larvae. All larvae given a single topical dose excreted precocene II for several days and were most efficient at eliminating smaller doses; larger, older larvae excreted more precocene II than smaller, younger larvae. Age-dependent responses to precocene II indicate that growth and metabolic processes, as well as xenobiotic metabolism, change in last instar larvae.
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  • 76
    ISSN: 1570-7458
    Keywords: (E,Z)-2,13-octadecadien-1-ol acetate ; (E,Z)-3,13-octadecadien-1-ol acetate ; Synanthedon tipuliformis ; Sesiidae ; Lepidoptera ; field trapping ; sex attractant ; geographical differences ; Belgium ; Bulgaria ; Denmark ; GDR ; Hungary ; Italy ; Lithuania ; Norway ; Soviet Union ; Switzerland ; United Kingdom
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  • 77
    ISSN: 1420-9071
    Keywords: Aldehyde dehydrogenase ; developmental changes ; gene expression
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    Topics: Biology , Medicine
    Notes: Summary Previous reports suggested that the major cytosolic aldehyde dehydrogenase (ALDH1) was present in fetal and infant livers, but the major mitochondrial isozyme (ALDH2) was absent or severely diminished. Re-examination by means of starch gel electrophoresis followed by enzyme activity staining, and by means of dot blot immuno-hybridization of liver samples with known genotypes of theALDH 2 locus, indicated that bothALDH 1 andALDH 2 genes are expressed in fetal and infant livers. In addition, ALDH4 isozyme was also observed. The results imply that a fetus with the ‘usual’ homozygousALDH 2 1 /ALDH 2 1 genotype, but not one with the atypicalALDH 2 1 /ALDH 2 2 orALDH 2 2 /ALDH 2 2 , is capable of detoxifying acetaldehyde transferred from the mother.
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  • 78
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    Cellular and molecular life sciences 47 (1991), S. 321-331 
    ISSN: 1420-9071
    Keywords: Symbiosis ; ectomycorrhiza ; ectomycorrhiza development ; gene expression ; ectomycorrhizins ; protein patterns
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary An ectomycorrhiza, a specialized root organ, is the result of a complex interaction leading to a finely-tuned symbiosis between a plant and a compatible ectomycorrhizal fungus. Ultrastructural observations combined with cytochemical and biochemical studies reveal that structural and metabolic changes in the symbiont cells lead to the final phenotype of the active ectomycorrhiza. In the present review these changes are interpreted as changes in gene expression and discussed within the context of ectomycorrhiza development. Recent genetic data indicate that the continued vegetative growth of the ectomycorrhizal hyphae and the root tissues, and their ability to switch to symbiotic organ formation, is basically controlled by developmentally critical genes. The activity of these ‘symbiotic genes’ during the differentiation of ectomycorrhizas is associated with extensive changes in the concentration of particular polypeptides and protein biosynthesis. The present state of knowledge about the developmental biology of ectomycorrhizas allows only speculation about the events during their development.
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  • 79
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    Cellular and molecular life sciences 49 (1993), S. 969-979 
    ISSN: 1420-9071
    Keywords: Climate change ; mortality ; heat stress ; vector-borne disease
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    Topics: Biology , Medicine
    Notes: Abstract The objective of this study is to discuss the potential impact of a global warming on various aspects of human health. Changes in heat-related mortality are estimated for four countries: the United States, Canada, the People's Republic of China and Egypt. In addition, the potential confounding impact of increased air pollution is considered. Finally, a framework to analyze two vector-borne diseases, onchocerciasis and malaria, which may spread if temperatures increase, is discussed. Our findings suggest that heat-related mortality is estimated to rise significantly in all four countries if the earth warms, with the greatest impacts in China and Egypt. The most sensitive areas are those with intense but irregular heat waves. In the United States, air pollution does not appear to impact daily mortality significantly when severe weather is present, although it seems to have a slight influence when weather conditions are not stressful.
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  • 80
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    Cellular and molecular life sciences 49 (1993), S. 133-137 
    ISSN: 1420-9071
    Keywords: Fetal hemoglobin ; sickle cell anemia ; β thalassemia ; butyrate ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The inherited β-hemoglobinopathies (sickle cell disease and β thalassemia) are the result of a mutation in the adult (β) globin gene. The fetal globin chain, encoded by the γ globin genes, can substitute for the mutated or defective β globin chain, but expression of the γ globin gene is developmentally inactivated prior to birth. Reinducing expression of the normal fetal globin genes is a preferred method of ameliorating sickle cell disease and the β thalassemias. Stimulation of as little as 4–8% fetal globin synthesis in the bone marrow can produce 〉20% fetal hemoglobin in the peripheral circulation, due to enhanced survival of red blood cells containing both sickle and fetal hemoglobin, compared to those containing sickle hemoglobin alone. Butyric acid and butyrate derivatives are generally safe compounds which induce fetal hemoglobin production by stimulating the promoter of the fetal globin genes. An initial trial with the parent compound, delivered as Arginine Butyrate, has demonstrated rapid stimulation of fetal globin expression to levels that have been shown to ameliorate these conditions. Phase 1 trials of an oral butyrate derivative with a long plasma half-life have just begun. These agents now provide a specific new apporach for ameliorating these classic molecular disorders and merit further investigation in larger patient populations.
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  • 81
    ISSN: 1420-9071
    Keywords: Ropalidia marginata ; primitively eusocial wasp ; queen success ; worker-brood genetic relatedness ; inclusive fitness theory ; Hymenoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Ropalidia marginata is a primitively eusocial polistine wasp in which, although there is only one queen at any given time, frequent queen replacements lead to a system of serial polygyny. One of the most striking features of this system, is the enormous variation in the success of different queens. Measuring queen success as queen tenure, total number of offspring produced, number of offspring produced per day of tenure, and proportion of eggs laid that develop into adults, we show here that each measure of queen success is correlated with worker-brood genetic relatedness and not correlated with worker: brood ratio or the age of the queen at takeover. We interpret these results as meaning that queens are better able to obtain the cooperation of workers when worker-brood genetic relatedness is high.
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  • 82
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    Cellular and molecular life sciences 50 (1994), S. 176-181 
    ISSN: 1420-9071
    Keywords: Cardiac glycoside loss ; Danaus plexippus ; aging ; breakdown of chemical defense ; three trophic level interactions ; automimicry ; Lepidoptera ; Asclepias
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    Topics: Biology , Medicine
    Notes: Abstract Monarch butterflies (Danaus plexippus) are unpalatable to various vertebrate predators because their larvae sequester bitter and emetic cardiac glycosides (CGs) from milkweed plants (Asclepias spp.). Here we show that the concentration of the defensive CGs decrease as individual butterflies age, regardless of the CGs' initial amounts or specific chemical structures. Consequently, individual monarch butterflies can change from being unpalatable models to palatable mimics during their lifetime. Since monarchs breed continuously over the spring and summer in North America, freshly emerged adult butterflies may serve as noxious models for older individuals which become automimics as they age.
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  • 83
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    Cellular and molecular life sciences 48 (1992), S. 414-416 
    ISSN: 1420-9071
    Keywords: Solitary bees ; lipid polymer ; silk ; CP/MAS13CNMR ; Hymenoptera ; Colletidae ; Hylaeus bisinuatus
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    Notes: Abstract The nest cell lining ofHylaeus bisinuatus (Hymenoptera: Colletidae) was shown by high-resolution solidstate [13C]NMR to be composed of lipid polymer and protein. The lipid polymer was shown by reduction and subsequent GC/MS analysis to be comprised of ω-hydroxy fatty acids (C20, C22, C24 and C26) and fatty alcohols (C16 to C30). The protein portion of the lining had a silk-like amino acid composition.
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  • 84
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    Cellular and molecular life sciences 50 (1994), S. 958-962 
    ISSN: 1420-9071
    Keywords: Plasminogen activator ; active oxygen ; gene expression ; radical scavengers ; endothelial cells
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    Notes: Abstract Active oxygen, produced by cultured cells following stimulation with various growth factors, seems to be involved in signal transduction leading to cellular responses such as gene expression and growth modulation. In the present study, the intracellular oxidation state was measured in immortalized human endothelial cells (ECV304) after treatment with tumor necrosis factor (TNF)α, using a fluorescent dye and a laser-scanning confocal microscope. The intracellular oxidation state was increased 60 min after the addition of TNFα, and this increase was abolished by a radical scavenger, N-acetylcysteine (NAC), which is also a precursor of glutathione, and by pyrrolidine dithiocarbamate (PDTC). TNFα increased the steady state level of urokinase-type plasminogen activator (uPA), and NAC inhibited this increase at a dose that also inhibited the increase in the intracellular oxidation state. PDTC, on the other hand, did not affect the induction of the uPA gene by TNFα. These results suggest that intracellular glutathione level rather than the oxidation state is necessary for the induction of the uPA gene by TNFα.
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  • 85
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    Cellular and molecular life sciences 49 (1993), S. 447-455 
    ISSN: 1420-9071
    Keywords: Proteoglycan ; chondroitin sulfate ; decorin ; gene expression ; tumor stroma ; DNA methylation
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    Notes: Abstract Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5′ untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon. Furthermore, a transforming growth factor beta (TGF-β)-negative element is present in the promoter region of decorin gene. This regulatory domain is likely to be implicated in the silencing of decorin gene by TGF-β and may contribute to the regulation of this matrix gene in the tumor stroma.
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  • 86
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    Cellular and molecular life sciences 49 (1993), S. 721-724 
    ISSN: 1420-9071
    Keywords: Lepidoptera ; Noctuidae ; Agrotis ipsilon ; black cutworm ; juvenile hormone ; allatectomy ; pheromone reception ; sexual behaviour ; tenoxycarb ; KK-42
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In Lepidoptera, reproduction is linked to chemical communication between conspecific partners. When exposed to the female sex pheromone, males respond by exhibiting typical sexual behaviour which leads to mating. Here we show that presence of the juvenile hormone producing gland (corpora allata) of the male black cutworm,Agrotis ipsilon, is necessary for pheromone responsiveness. Allatectomized males do not show any sexual behaviour, although their antennal olfactory system is functional. Allatectomized males implanted with active corpora allata recover full pheromone receptivity. It is suggested that reproductive processes are synchronized in males and females through endocrine control; timing of the mating activity could serve as an adaptive strategy linked to the migratory behaviour of this species.
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  • 87
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    Entomologia experimentalis et applicata 59 (1991), S. 207-217 
    ISSN: 1570-7458
    Keywords: Insect behavior ; Heliothis zea ; Lepidoptera ; Noctuidae ; precocene II ; methylenedioxy-precocene ; toxicity ; growth inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In diet choice tests, newly-ecdysed fifth instar Heliothis zea larvae randomly chose diet containing 4 mM precocene II or diet without precocene II but initially preferred to feed on diet without precocene II. After two days, however, they were found more frequently on diet containing precocene II. Nevertheless, larval growth and development were inhibited when forced to eat diet containing precocene II. Removal of the maxillae, the site of the primary gustatory receptors, did not prevent the growth inhibition caused by larval consumption of diet with precocene II. Topical treatments with precocene II also caused larval growth inhibition, and daily treatments were more detrimental to the larvae than a large single dose. Addition of methylenedioxyprecocene (6,7-methylenedioxy-2,2-dimethylchromene) to the diet did not reverse the observed larval growth inhibition and this compound was itself significantly toxic. These results indicate that larval growth and development are disrupted after precocene II ingestion, but not because of preingestive discrimination by olfaction and gustation.
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  • 88
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    Entomologia experimentalis et applicata 56 (1990), S. 23-30 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Mamestra brassicae ; sex pheromone ; calling behaviour ; calling posture ; diel periodicity of calling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé La périodicité quotidienne de l'appel et les effets de l'âge et de la photopériode ont été examinés sur des femelles vierges deMamestra brassicae (Lépido., Noctuidae). Aucun appel n'a été observé pendant la première scotophase; la plupart des femelles appelaient pour la première fois pendant les 2e et 3e scotophases après l'émergence, quelle que fût la photopériode. Les papillons conservés à 16 J/8 N ont commencé à appeler beaucoup plus tard que ceux dont la photopériode était 18 J/6 N. En vieillissant, les papillons appelaient significativement de plus en plus tôt. Avec 16 J/8 N, la moyenne du moment du début de l'appel a diminué de la scotophase 2 à la scotophase 3, après laquelle il s'est stabilisé autour de 260 min après le début de la scotophase. Avec 18 J/6 N, le moment du début de l'appel a diminué jusqu'à la scotophase 4, et s'est stabilisé ensuite autour de 130 min après le début de l'obscurité.
    Notes: Abstract Die periodicity of calling and the effect of age and photoperiod on calling behaviour were studied in virgin females of the cabbage moth,mamestra brassicae L. (Lepidoptera: Noctuidae). No calling activity was observed during the first scotophase. Most females called for the first time during the 2nd or 3rd scotophase after emergence, regardless of the photoperiod. Moths maintained under 16L: 8D started calling significantly later in the scotophase than those maintained under 18L: 6D. With increasing age, moths initiated calling significantly earlier. Under the 16L: 8D photoregime, the mean onset calling time decreased from scotophases 2 to 3, after which it stabilized around ca. 260 min after the start of the scotophase. With 18L: 6D, the onset of calling decreased until scotophase 4, and subsequently stabilized around ca. 130 min after lights off.
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  • 89
    ISSN: 1570-7458
    Keywords: Diapause termination ; postdiapause development ; development threshold ; thermal constant ; Aphelinus mali ; Hymenoptera ; Aphelinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'achèvement de la diapause en conditions naturelles ou simulant l'hiver, les effets des températures inférieures à zéro sur le développement après la diapause et les relations entre la vitesse de développement après la diapause et les températures constantes ou en thermopériodes ont été examinés sur des populations néerlandaises d'A. mali (Hymenop.; Aphélinidae). Les taux d'achèvement de la diapause de larves hivernantes étaient semblables en conditions naturelles ou simulées. La plupart des larves ont terminé leur diapause la dernière semaine de février. Quelques larves femelles sont restées en diapause jusqu'à fin mars. L'exposition pendant 2 semaines des larves sorties de diapause à −10 °C ne compromet pas leur survie ou leur taux de développement après la diapause. Les larves ayant diapause peuvent terminer leur développement et les adultes émerger des pucerons momifiés aux températures constantes comprises entre 12 et 24 °C. Bien que quelques larves achèvent leur développement à 10 °C, peu émergent. La température seuil théorique de développement après la diapause (to) a été de 9,4 °C et la constante thermique (K), 136,5 degrés-jours. Pour la première émergence et pour 50% d'émergences, les valeurs de K étaient respectivement: 121,4 et 134,8. Le nombre d'unités thermiques pour la première émergence et pour 50% d'émergences était le même à température constante ou avec une thermopériode.
    Notes: Abstract Diapause termination under natural and simulated overwintering conditions, the effect of subzero temperature on postdiapause development and the relationship between postdiapause development rate and constant and fluctuating temperatures was studied in a Dutch population ofAphelinus mali Hald. (Hymenoptera: Aphelinidae). The rate of diapause termination was similar in larvae overwintering under natural and simulated conditions. Most larvae had terminated diapause by the last week of February. Some female larvae may have remained in diapause until the end of March. The exposure of postdiapause larvae to −10°C for two weeks did not affect their survival or postdiapause development rate. PostdiapauseA. mali larvae could complete development and the adults emerge from their mummified aphid hosts at constant temperatures from 12 to 24°C. Although some larvae completed postdiapause development at 10°C, few emerged. The theoretical threshold temperature (to) for postdiapause development was 9.4°C and the thermal constant (K) 136.4 degree-days. K was 121.4 and 134.8 for first and 50% emergence, respectively. The number of heat units accumulating above 9.4°C to 1st and 50% emergence was similar under constant and fluctuating temperatures.
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  • 90
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    Entomologia experimentalis et applicata 59 (1991), S. 111-122 
    ISSN: 1570-7458
    Keywords: Yponomeuta evonymellus ; Yponomeuta padellus ; Prunus padus ; Crataegus monogyna ; Lepidoptera ; monophagous ; oligophagous ; host-plants ; food-acceptance ; seasonal changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Food acceptance by larvae of two lepidopteran species feeding on Rosaceae, viz. Yponomeuta evonymellus (monophagous) and Y. padellus (oligophagous), was compared. The influence of seasonal changes in plants as food for both insects was examined, in particular, the effects of nitrogen and sorbitol in leaves. In the laboratory, Y. evonymellus accepts Crataegus monogyna, a host plant of Y. padellus, and Y. padellus accepts Prunus padus, the host plant of Y. evonymellus. P. padus is the most suitable food plant for Y. evonymellus. No difference in food-quality for Y. padellus was found between C. monogyna and P. padus. The performance of both species on P. padus is less influenced by seasonal changes than on Crataegus. The suitability of Crataegus decreases during the season. This is probably caused by the decrease of its nitrogen content, and not by the decrease of sorbitol in the plant. The monophagous, Y. evonymellus, is more sensitive to seasonal changes in its food when fed with a non host plant than the oligophagous Y. padellus. In oviposition experiments both species have a preference for their normal host-plants.
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  • 91
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    Entomologia experimentalis et applicata 61 (1991), S. 131-138 
    ISSN: 1570-7458
    Keywords: Calling ; mating ; relative humidity ; age ; reproduction ; Ostrinia nubilalis ; European corn borer ; Pyralidae ; Lepidoptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Nous avons étudié le comportement d'appel des femelles vierges d'Ostrinia nubilalis maintenues sous trois conditions constantes d'humidité relative, depuis l'émergence jusqu'à la sixième nuit d'appel, ainsi que l'incidence d'accouplement d'individus placés en milieu sec ou humide pour diverses périodes de temps. Les conditions d'humidité n'ont pas significativement affecté l'âge moyen auquel les femelles ont commencé à appeler au cours de leur vie, bien qu'il ait été plus variable à 53% h.r. Les nuits subséquentes, le comportement d'appel des femelles maintenues à basse humidité a débuté plus tard dans la nuit, s'est exprimé pour une période de temps plus courte avec moins de séquences d'appel que celui de leurs congénères placés en milieu humide, et la proportion de femelles en appel a toujours été plus faible à 53% h.r. Ces changements du comportement préreproducteur des femelles se sont répercutés sur l'incidence d'accouplement qui, les deux premiers jours suivant lémergence, a été significativement plus faible à basse humidité qu'elle ne l'a été en milieu humide. Ces résultats seront discutés en relation avec l'écologie de O. nubilalis et associés à sa susceptibilité à la dessication.
    Notes: Abstract We examined the calling behaviour of O. nubilalis virgin females, held at three different constant conditions of relative humidity from the time of emergence through their sixth night of calling, as well as the incidence of mating over time at low or high relative humidity conditions. The mean age at which females initiated calling in their life was independent of relative humidity conditions, although more variable at low humidity. On successive nights of calling, fewer virgin European corn borer females called under low compared with high humidity conditions, and those that did began later in scotophase, had fewer calling bouts, and spent less time calling. These changes in the female prereproductive behaviour were reflected on the incidence of mating which, in the first two days following emergence, was significantly less at low than at high humidity conditions. The ecological significance of these results is discussed in relation with the susceptibility of O. nubilalis to desiccation.
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  • 92
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    Entomologia experimentalis et applicata 62 (1992), S. 29-36 
    ISSN: 1570-7458
    Keywords: Alkaloids ; cinnabar moth ; insect genetics ; larval performance ; Lepidoptera ; nutritional ecology ; nitrogen ; sugar ; Tyria jacobaeae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a laboratory experiment using full-sibs, 60% of the variation in pupal weight of the monophage Tyria jacobaeae L. (Lepidoptera, Arctiidae) could be explained by variation in the nitrogen concentration of the food plant, Senecio jacobaea L. and only 4% by variation in sugar concentration. Larval weight and growth rates of young and old larvae were also positively correlated with nitrogen and sugar concentration. Developmental time was negatively correlated with nitrogen concentration. In a second experiment full-sib families differed significantly in larval weight at day 7, mortality, growth rate and developmental time. Pupal weight did not differ significantly among families, but was positively correlated with nitrogen concentration of Senecio. Larval performance was not significantly influenced by concentrations of sugars or alkaloids. We conclude that larval performance of Tyria during most of the larval period is mainly determined by genetic factors, but pupal weights are primarily determined by nitrogen concentration of the food plant.
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    Entomologia experimentalis et applicata 55 (1990), S. 1-10 
    ISSN: 1570-7458
    Keywords: Parasitoid ; hemocytes ; inhibition of encapsulation ; Hymenoptera ; Lepidoptera hosts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'ichneumonide Campoletis sonorensis Carlson, endoparasitoïde larvaire, se développe dans de nombreuses espèces de Lépidoptères. Son statut de généraliste est dû, notamment, à son aptitude à déjouer les défenses immunitaires de ses hôtes, c.a.d. la formation d'une capsule d'hémocytes autour de l'oeuf ou de la larve parasite. Cependant, chez le noctuide Spodoptera frugiperda J.E. Smith, C. sonorensis est encapsulé dans 40% des larves qu'il parasite. Nous avons étudié la population hémocytaire de deux catégories de larves de S. frugiperda, celles qualifiées de ‘résistantes’ à C. sonorensis, et qui arrêtent son développement, et celles ‘susceptibles’ où le parasitoïde échappe à l'encapsulation. Cinq types d'hémocytes ont été identifiés: les prohémocytes (PR), les sphérulocytes (SP), les granulocytes (GR), les plasmatocytes (PL) et les oenocytoïdes (OE). Chez les hôtes susceptibles et résistants, le parasite provoque une baisse identique de la concentration totale des hémocytes dans l'hémolymphe (THC). Par contre, les PLs sont davantage affectés chez les hôtes susceptibles que chez ceux résistants au parasitoïde. Les résultats montrent que, chez les hôtes susceptibles, 1) le nombre des PLs dans l'hémolymphe est davantage diminué, et 2) leur aptitude d'adhérence in vitro est davantage inhibée. Il existe donc une corrélation positive entre le degré de pathologies qui affectent les PLs de l'hôte et l'incapacité de celui-ci à encapsuler le parasitoïde. Ceci tend à démontrer le rôle-clé des PLs dans la réaction immunitaire d'encapsulation chez S. frugiperda, comme chez de nombreux insectes. De plus, ce résultat renforce l'hypothèse selon laquelle C. sonorensis éviterait l'encapsulation en agissant sur les hémocytes de l'hôte, et plus particulièrement sur les PLs. Inversement aux PLs, les GRs sont moins abondants dans l'hémolymphe des hôtes qui encapsulent C. sonorensis. Les GRs pourraient donc participer à la formation de la capsule hémocytaire. Il est possible que plusieurs facteurs contribuent à protéger C. sonorensis de l'encapsulation. Néanmoins, les pathologies affectant les hémocytes des hôtes parasités sont probablement une manifestation majeure de l'effet immunosuppresseur du parasitoïde. Les effets de C. sonorensis sur les hémocytes des larves parasitées peuvent être reproduits chez des larves saines, en leur injectant de ‘venin’ extrait des glandes du calyx des femelles parasitoïdes. Ces sécrétions provenant de la glande du calyx, et normalement injectées dans l'hôte lors de l'oviposition, sont probablment responsable, au moins en partie, de l'effet immunosuppresseur du parasitoïde. Ces résultats peuvent être comparés à ceux obtenus chez l'hôte Heliothis virescens Fabricius (lépidoptère, noctuide) qui n'encapsule jamais C. sonorensis. Bien que le parasitoïde provoque les mêmes effets pathologiques sur les hémocytes des hôtes de S. frugiperda et d'H. virescens, on constate que l'effet apparait quelques heures après l'oviposition chez H. virescens, contre 48 heures post-oviposition chez S. frugiperda. Ce délai pourrait contribuer à la résistance immunitaire de certaines larves de S. frugiperda, ‘résistantes’, à C. sonorensis.
    Notes: Abstract The egg and larval stages of the generalist endoparasitoid Campoletis sonorensis Carlson (Hymenoptera: Ichneumonidae), which normally avoid the hemocytic reaction of many Lepidopteran host species, are encapsulated in 40% of Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) larvae. The effect of parasitism on inhibiting the spreading ability of S. frugiperda plasmatocytes in vitro is more pronounced in susceptible larvae which fail to encapsulate the parasitoid than in resistant ones permitting parasitoid development. This suggests that induction of plasmatocyte pathology is relevant to the successful evasion of encapsulation by the parasitoid. Some granular cells disappear from the hemolymph of the parasitized resistant larvae, which implicates their involvement in the encapsulation reaction. Calyx fluid of C. sonorensis injected into host larvae produced effects on host hemocytes identical to natural parasitism. Several mechanism may cooperate to protect the parasitoid from encapsulation. The pathological reactions by the host plasmatocytes is one main manifestation of the ‘immunosuppressive’ parasitoid effect. Results are discussed in regard to the known effects of C. sonorensis on Heliothis virescens Fabricius (Lepidoptera: Noctuidae) larval hemocytes which are totally unable to respond with a successful cellular defense reaction.
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  • 94
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    Entomologia experimentalis et applicata 65 (1992), S. 81-93 
    ISSN: 1570-7458
    Keywords: Heliothis virescens ; Lepidoptera ; Noctuidae ; feeding behavior ; oviposition behavior ; electrophysiology ; deterrence ; antifeedant ; quinine ; quinidine ; atropine ; caffeine ; denatonium benzoate ; naringin ; sucrose octaacetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some compounds that are bitter-tasting to humans, both alkaloidal (quinine, quinidine, atropine, caffeine) and non-alkaloidal (denatonium benzoate, sucrose octaacetate, naringin), deterred feeding and oviposition by Heliothis virescens (F.) in laboratory and field cage experiments. Preliminary electrophysiological studies of gustatory sensilla on the ovipositor of H. virescens provided evidence of 3 neurons, one of which is responsive to sucrose. Preliminary indications are that responses of this neuron may be inhibited by quinine and denatonium benzoate.
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  • 95
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    Entomologia experimentalis et applicata 65 (1992), S. 199-204 
    ISSN: 1570-7458
    Keywords: Sesamia nonagrioides ; Lepidoptera ; Noctuidae ; calling behaviour ; mating behaviour ; circadian rhythm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mating behaviour of the corn stalk borerSesamia nonagrioides (Lef.) [Lepidoptera:Noctuidae] was studied under laboratory conditions at 25 ± 1 °C, 65 ± 5% r.h. and 16:8 (L:D) regime. The females began calling during the first scotophase following emergence, the peak of calling occurred during the second scotophase and thereafter decreased. Maximum calling was observed between the fourth and sixth hour of the scotophase. The calling pattern varied with age. During the first and second scotophase most of the females were calling continuously, while during the third and fourth scotophase periodic calling was observed. The mean onset of calling was advanced and the mean length of calling per day was increased slightly as the female became older. Females held for 72 h in continuous darkness exhibited an endogenous circadian rhythm of calling. Matings began during the first scotophase following emergence and the peak of mating was observed during the second scotophase. Mated females did not remate. Few males mated more than once during the following scotophases.
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  • 96
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    Entomologia experimentalis et applicata 66 (1993), S. 31-38 
    ISSN: 1570-7458
    Keywords: Eurytoma amygdali ; Hymenoptera ; Eurytomidae ; egg distribution ; superparasitism ; host discrimination ; oviposition behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The egg distribution patterns ofEurytoma amygdali Enderlein (Hymenoptera, Eurytomidae), which oviposits singly in green, developing almonds, were studied in the laboratory and in the field. In the laboratory, individual females were caged with a number of almonds and the eggs deposited in each fruit were counted. In the field, eggs were censused in almonds of different varieties at regular intervals, over four seasons (1988–91). In the susceptible ‘Retsou’ variety, eggs were uniformly distributed among fruits, both in the laboratory and in the field, as long as the mean number of eggs per almond was ≤2.5. When the mean number of eggs per almond was higher the egg distributions were random. This suggests that, up to a certain level of infestation, females were able to assess egg load of fruits and oviposit in the less infested ones. The main factor enabling the females to discriminate and select the less infested almonds for oviposition is probably a host-marking pheromone. In 1990, the same patterns of egg distribution were observed in samples taken from 5 other almond varieties that are not as susceptible as Retsou and have thicker pericarp and harder endocarp. In 1991 however, when fruits developed more rapidly than in 1990, egg distributions in 3 of these 5 varieties (Truoito, Ai, and Marcona) were not uniform. Although the mean number of eggs per fruit was low (1.2–2.0), many fruits of these varieties contained no eggs. This suggests that, in some less susceptible varieties, egg distribution might also be affected by certain fruit parameters, unfavourable for oviposition, related to the pericarp thickness and endocarp hardness.
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  • 97
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    Journal of comparative physiology 171 (1992), S. 289-297 
    ISSN: 1432-1351
    Keywords: Electrophysiology ; Lepidoptera ; Photoreceptor ; Spectral sensitivity ; Vision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. A butterfly Papilio has 5 types of spectral receptors in the compound eye. The spectral sensitivity of each type peaks in the UV, violet, blue, green, and red wavelengths, respectively. The green type contains two subtypes with and without a UV secondary peak. Here we studied the localization of these spectral receptors within the ommatidium. 2. An ommatidium contains 9 photoreceptors (R1–9), each of which is one of the 5 spectral receptor types. The photoreceptors bear parallel microvilli to form a nontwisted rhabdom, and thereby the photoreceptors are polarization sensitive. 3. We first examined the microvillar orientation by electron microscopy. The microvilli of R1, 2, and 9 are oriented dorso-ventrally (0°), whereas those of R3 and 4 are parallel to the antero-posterior axis (90°). The R5–8 bear microvilli diagonally: 45° for R6 and R8, 135° for R5 and R7. 4. We then recorded spectral and polarization sensitivities from single photoreceptors. The peak angle of the polarization sensitivity (θmax) of the UV, violet, and blue receptors were around 0°, whereas that of the green receptors was around 90°. In the double-peaked green receptors, the θmax at UV was also around 90°. The red receptors showed a θmax at around 35°. The polarization sensitivity ratio (PSmax/PSmin) of the double-peaked green receptors measured at UV was around 4, whereas the ratio of other receptors was around 2. 5. We conclude that R1 and R2 are either UV, violet, or blue receptors whereas R3 and R4 are green receptors. Some R6 and R8 are red receptors. We also conclude that the UV secondary peak in the double-peaked green receptor is not simply attributable to the coupling with UV receptors.
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  • 98
    ISSN: 1432-1351
    Keywords: Carbon dioxide ; Chemoreception ; Lepidoptera ; Microclimate ; Sensory transduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In recordings of single unit action potentials, the responses of CO2-receptors in the labial palp organ of the moth Heliothis armigera to modulation of CO2-density around a background of 350 ppm were investigated. Modulation of CO2-density by square wave changes in concentration at constant barometric pressure evokes modulation of the spike rate. Modulation of CO2-density by square wave changes in barometric pressure at constant CO2-concentration evokes responses similar to those evoked by concentration modulation. For modulation depths of less than 1.5%, the output modulation depth is linearly related to the input; at higher modulation depths the gain decreases progressively. Using sinusoidal pressure modulation, the frequency dependence of both gain and output noise was determined over a range of 0.05 to 12.8 Hz. With increasing frequency the gain progressively increases at a rate of 2.4 dB/octave up to a maximum of 63 at 3 Hz; at higher frequencies, it decreases rapidly. The threshold sensitivity of the receptors, using input noise amplitude density as a criterion, is broadly tuned, with a minimum of 1 % contrast Hz-0.5 between 0.3 and 3 Hz. Using these figures, it is concluded that the sensory organ is capable of detecting fluctuations in CO2-density of 0.14% or 0.5 ppm. The results are related to the fluctuations in CO2-density which occur in a natural environment.
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  • 99
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    Journal of comparative physiology 171 (1992), S. 171-181 
    ISSN: 1432-1351
    Keywords: Colour vision ; Flower colours ; Evolution ; Hymenoptera ; Pollination ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The evolutionary tuning between floral colouration and the colour vision of flower-visiting Hymenoptera is quantified by evaluating the informational transfer from the signalling flower to the perceiving pollinator. The analysis of 180 spectral reflection spectra of angiosperm blossoms reveals that sharp steps occur precisely at those wavelengths where the pollinators are most sensitive to spectral differences. Straight-forward model calculations determine the optimal set of 3 spectral photoreceptor types for discrimination of floral colour signals on the basis of perceptual difference values. The results show good agreement with the sets of photoreceptors characterized electrophysiologically in 40 species of Hymenoptera.
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    Journal of comparative physiology 175 (1994), S. 363-369 
    ISSN: 1432-1351
    Keywords: Hymenoptera ; Bees ; Homing ; Landmark guidance ; Distance perception
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Bees and wasps acquire a visual representation of their nest's environment and use it to locate their nest when they return from foraging trips. This representation contains among other features cues to the distance of near-by landmarks. We worked with two species of ground-nesting bees, Lasioglossum malachurum (Hymenoptera: Halictidae), Dasypoda hirtipes (Hymenoptera: Melittidae) and asked which cues to landmark distance they use during homing. Bees learned to associate a single cylindrical landmark with their nest's location. We subsequently tested returning bees with landmarks of different sizes and thus introduced large discrepancies between the angular size of the landmark as seen from the nest during training and its distance from the nest. The bees' search behaviour and their choice of dummy nest entrances show that both species of ground-nesting bees consistently search for their nest at the learned distance from landmarks. The influence of the apparent size of landmarks on the bees' search and choice behaviour is comparatively weak. We suggest that the bees exploit cues derived from the apparent speed of the landmark's image at their retina for distance evaluation.
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