380 research outputs found

    Response of arthropod species richness and functional groups to urban habitat structure and management

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    Urban areas are a particular landscape matrix characterized by a fine-grained spatial arrangement of very diverse habitats (urban mosaic). We investigated arthropods to analyse biodiversity-habitat associations along five environmental gradients (age, impervious area, management, configuration, composition) in three Swiss cities (96 study sites). We considered total species richness and species richness within different functional groups (zoophagous, phytophagous, pollinator, low mobility, and high mobility species). Information theoretical model selection procedures were applied and predictions were calculated based on weighted models. Urban areas yielded on average 284 arthropod species (range: 169-361), with species richness correlating mostly with heterogeneity indices (configuration and composition). Species richness also increased with age of urban settlement, while enlarged proportions of impervious area and intensified habitat management was negatively correlated. Functional groups showed contrasted, specific responses to environmental variables. Overall, we found surprisingly little variation in species richness along the gradients, which is possibly due to the fine-grained spatial interlinkage of good (heterogeneous) and bad (sealed) habitats. The highly fragmented nature of urban areas may not represent a major obstacle for the arthropods currently existing in cities because they have probably been selected for tolerance to fragmentation and for high colonisation potential. Given that built areas are becoming denser, increasing spatial heterogeneity of the urban green offers potential for counteracting the detrimental effects of densification upon urban biodiversity. By quantifying the expected effects along environmental gradients, this study provides guidance for managers to set priorities when enhancing urban arthropod species richnes

    Control of Pre-mRNA Splicing by the General Splicing Factors PUF60 and U2AF65

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    Pre-mRNA splicing is a crucial step in gene expression, and accurate recognition of splice sites is an essential part of this process. Splice sites with weak matches to the consensus sequences are common, though it is not clear how such sites are efficiently utilized. Using an in vitro splicing-complementation approach, we identified PUF60 as a factor that promotes splicing of an intron with a weak 3' splice-site. PUF60 has homology to U2AF(65), a general splicing factor that facilitates 3' splice-site recognition at the early stages of spliceosome assembly. We demonstrate that PUF60 can functionally substitute for U2AF(65)in vitro, but splicing is strongly stimulated by the presence of both proteins. Reduction of either PUF60 or U2AF(65) in cells alters the splicing pattern of endogenous transcripts, consistent with the idea that regulation of PUF60 and U2AF(65) levels can dictate alternative splicing patterns. Our results indicate that recognition of 3' splice sites involves different U2AF-like molecules, and that modulation of these general splicing factors can have profound effects on splicing

    Ants impact the energy reserves of natural enemies through the shared honeydew exploitation

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    [EN] Ants, as well as many species of parasitoids and predators, rely on sugar-richfoodssuchashoneydewtofulfilltheirenergeticneeds.Thus,antsandnatural enemies may interact through the shared honeydew exploitation. 2.Ant-exclusionexperimentswereperformedinacitrusorchardtotestthehypothesis that ants may impact the energy reserves of predators and parasitoids through the competitionforhoneydew.Throughtheuseofhigh-performanceliquidchromatography (HPLC)thelevelofantactivitywiththeenergyreservesandfeedinghistoryofindividual specimens collected in the field during representative days of spring, summer, and autumn were related. 3. Out of 145 Aphytis chrysomphali Mercet parasitoids captured in the field, 65% were classified as sugar-fed and 24.7% as honeydew-fed. In summer, when ant activity peaked,therewasasignificant negativecorrelationbetweenthelevelofantactivityand the total sugar content and honeydew feeding incidence by A.chrysomphali. Out of 47 individuals of the predator Chrysoperla carnea sensu lato (Stephens), captured in the field, 55.3% were classified as sugar-fed. We found a significant negative effect of the level of ant activity on the sugar-feeding incidence by C.carneain spring. 4.Thepresentstudyprovidesevidencethatantscaninterferewiththeenergyreserves of natural enemies. This interaction may be widespread in various ecosystems with important consequences for the arthropod community composition and with practical implicationsforbiologicalcontrolgiventhatabsenceofsugarfeedingisdetrimentalfor thefitness of many species of predatorsand parasitoidsDr Jerome Casas is greatly acknowledged for valuable comments on earlier versions of the manuscript and Dr Petr Duelli for providing help with the Chrysoperla identifications. We also thank Dr Cristina Navarro Campos and Dr Aleixandre Beltra for their help in the field samplings and for stimulating discussions, Barbara Rodriguez for help in the laboratory analyses and the reviewers for their helpful comments. This work was supported by the project (RTA2010-00012-C02-02) assigned to F. G. M from the Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Spain and the project (BIO2013-48779-C4-1-R) from Spanish Ministry of Science and Innovation and COST action CM1303 on Systems Biocatalysis.Calabuig Gomar, A.; Tena Barreda, A.; Wäkers, FL.; Lucia Fernandez-Arrojo; Plou, FJ.; García Mari, F.; Pekas, A. (2015). Ants impact the energy reserves of natural enemies through the shared honeydew exploitation. Ecological Entomology. 40:687-695. https://doi.org/10.1111/een.12237S68769540Avidov, Z., Balshin, M., & Gerson, U. (1970). Studies onAphytis coheni, a parasite of the California red scale,Aonidiella aurantii in Israel. 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Colonisation of Aphytis melinus DeBach (Hymenoptera, Aphelinidae) in Aonidiella aurantii (Mask.) (Hemiptera, Coccidae) on citrus in South Australia. Bulletin of Entomological Research, 65(4), 659-668. doi:10.1017/s0007485300006350Carroll, C. R., & Janzen, D. H. (1973). Ecology of Foraging by Ants. Annual Review of Ecology and Systematics, 4(1), 231-257. doi:10.1146/annurev.es.04.110173.001311Cerdá, X., Palacios, R., & Retana, J. (2009). Ant Community Structure in Citrus Orchards in the Mediterranean Basin: Impoverishment as a Consequence of Habitat Homogeneity. Environmental Entomology, 38(2), 317-324. doi:10.1603/022.038.0203DUELLI, P. (1980). Adaptive dispersal and appetitive flight in the green lacewing, Chrysopa cornea. Ecological Entomology, 5(3), 213-220. doi:10.1111/j.1365-2311.1980.tb01144.xDuelli, P. (1980). Preovipository migration flights in the green lacewing, Chrysopa carnea (Planipennia, Chrysopidae). Behavioral Ecology and Sociobiology, 7(3), 239-246. doi:10.1007/bf00299370Eubanks, M. D., & Finke, D. L. (2014). Interaction webs in agroecosystems: beyond who eats whom. Current Opinion in Insect Science, 2, 1-6. doi:10.1016/j.cois.2014.06.005Faria, C. A., Wäckers, F. L., & Turlings, T. C. J. (2008). The nutritional value of aphid honeydew for non-aphid parasitoids. Basic and Applied Ecology, 9(3), 286-297. doi:10.1016/j.baae.2007.02.001Finney, G. L. (1948). Culturing Chrysopa californica and Obtaining Eggs for Field Distribution. Journal of Economic Entomology, 41(5), 719-721. doi:10.1093/jee/41.5.719HEIMPEL, G. E., & COLLIER, T. R. (1996). THE EVOLUTION OF HOST-FEEDING BEHAVIOUR IN INSECT PARASITOIDS. Biological Reviews, 71(3), 373-400. doi:10.1111/j.1469-185x.1996.tb01279.xHeimpel, G. E., Rosenheim, J. A., & Mangel, M. (1997). Predation on adult Aphytis parasitoids in the field. Oecologia, 110(3), 346-352. doi:10.1007/s004420050168Heimpel, G. E., Rosenheim, J. A., & Kattari, D. (1997). Adult feeding and lifetime reproductive success in the parasitoid Aphytis melinus. Entomologia Experimentalis et Applicata, 83(3), 305-315. doi:10.1046/j.1570-7458.1997.00185.xHOGERVORST, P. A. M., WÄCKERS, F. L., & ROMEIS, J. (2007). Detecting nutritional state and food source use in field-collected insects that synthesize honeydew oligosaccharides. Functional Ecology, 21(5), 936-946. doi:10.1111/j.1365-2435.2007.01297.xHölldobler, B., & Wilson, E. O. (1990). The Ants. doi:10.1007/978-3-662-10306-7Holway, D. A., Lach, L., Suarez, A. V., Tsutsui, N. D., & Case, T. J. (2002). The Causes and Consequences of Ant Invasions. Annual Review of Ecology and Systematics, 33(1), 181-233. doi:10.1146/annurev.ecolsys.33.010802.150444James, D. G., Stevens, M. M., O’Malley, K. J., & Faulder, R. J. (1999). Ant Foraging Reduces the Abundance of Beneficial and Incidental Arthropods in Citrus Canopies. Biological Control, 14(2), 121-126. doi:10.1006/bcon.1998.0678JERVIS, M. A., & KIDD, N. A. C. (1986). HOST-FEEDING STRATEGIES IN HYMENOPTERAN PARASITOIDS. Biological Reviews, 61(4), 395-434. doi:10.1111/j.1469-185x.1986.tb00660.xJervis, M. A., Kidd, N. A. C., Fitton, M. G., Huddleston, T., & Dawah, H. A. (1993). Flower-visiting by hymenopteran parasitoids. Journal of Natural History, 27(1), 67-105. doi:10.1080/00222939300770051Kaplan, I., & Eubanks, M. D. (2005). APHIDS ALTER THE COMMUNITY-WIDE IMPACT OF FIRE ANTS. Ecology, 86(6), 1640-1649. doi:10.1890/04-0016Lach, L. (2007). Argentine ants displace floral arthropods in a biodiversity hotspot. Diversity and Distributions, 14(2), 281-290. doi:10.1111/j.1472-4642.2007.00410.xLaverty, T. M., & Plowright, R. C. (1985). Competition between hummingbirds and bumble bees for nectar in flowers of Impatiens biflora. Oecologia, 66(1), 25-32. doi:10.1007/bf00378548LeVan, K. E., Hung, K.-L. J., McCann, K. R., Ludka, J. T., & Holway, D. A. (2013). Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens. Oecologia, 174(1), 163-171. doi:10.1007/s00442-013-2739-zTeresa Martinez-Ferrer, M., Grafton-Cardwell, E. E., & Shorey, H. H. (2003). Disruption of parasitism of the California red scale (Homoptera: Diaspididae) by three ant species (Hymenoptera: Formicidae). Biological Control, 26(3), 279-286. doi:10.1016/s1049-9644(02)00158-5McEwen, P. K., Clow, S., Jervis, M. A., & Kidd, N. A. C. (1993). Alteration in searching behaviour of adult female green lacewingsChrysoperla carnea (Neur.: Chrysopidae) following contact with honeydew of the black scaleSaissetia oleae (Hom.: Coccidae) and solutions containing acidhydrolysed L-tryptophan. Entomophaga, 38(3), 347-354. doi:10.1007/bf02374452Miller, T. E. (1994). Direct and Indirect Species Interactions in an Early Old-Field Plant Community. The American Naturalist, 143(6), 1007-1025. doi:10.1086/285646Moreno, D. S., Haney, P. B., & Luck, R. F. (1987). Chlorpyrifos and Diazinon as Barriers to Argentine Ant (Hymenoptera: Formicidae) Foraging on Citrus Trees1. Journal of Economic Entomology, 80(1), 208-214. doi:10.1093/jee/80.1.208Ohgushi, T. (2008). Herbivore‐induced indirect interaction webs on terrestrial plants: the importance of non‐trophic, indirect, and facilitative interactions. Entomologia Experimentalis et Applicata, 128(1), 217-229. doi:10.1111/j.1570-7458.2008.00705.xOLSON, D. M., & WÄCKERS, F. L. (2006). Management of field margins to maximize multiple ecological services. Journal of Applied Ecology, 44(1), 13-21. doi:10.1111/j.1365-2664.2006.01241.xPace, M. L., Cole, J. J., Carpenter, S. R., & Kitchell, J. F. (1999). Trophic cascades revealed in diverse ecosystems. Trends in Ecology & Evolution, 14(12), 483-488. doi:10.1016/s0169-5347(99)01723-1Pekas, A., Aguilar, A., Tena, A., & Garcia-Marí, F. (2010). Influence of host size on parasitism by Aphytis chrysomphali and A. melinus (Hymenoptera: Aphelinidae) in Mediterranean populations of California red scale Aonidiella aurantii (Hemiptera: Diaspididae). Biological Control, 55(2), 132-140. doi:10.1016/j.biocontrol.2010.07.010Pekas, A., Tena, A., Aguilar, A., & Garcia-Marí, F. (2010). Effect of Mediterranean Ants (Hymenoptera: Formicidae) on California Red Scale (Hemiptera: Diaspididae) Populations in Citrus Orchards. Environmental Entomology, 39(3), 827-834. doi:10.1603/en09207Pekas, A., Tena, A., Aguilar, A., & Garcia-Marí, F. (2010). Spatio-temporal patterns and interactions with honeydew-producing Hemiptera of ants in a Mediterranean citrus orchard. Agricultural and Forest Entomology, 13(1), 89-97. doi:10.1111/j.1461-9563.2010.00501.xRosen, D., & DeBach, P. (1979). Species of Aphytis of the World. doi:10.1007/978-94-009-9603-8Rosumek, F. B., Silveira, F. A. O., de S. Neves, F., de U. Barbosa, N. P., Diniz, L., Oki, Y., … Cornelissen, T. (2009). Ants on plants: a meta-analysis of the role of ants as plant biotic defenses. Oecologia, 160(3), 537-549. doi:10.1007/s00442-009-1309-xRudgers, J. A., & Gardener, M. C. (2004). EXTRAFLORAL NECTAR AS A RESOURCE MEDIATING MULTISPECIES INTERACTIONS. Ecology, 85(6), 1495-1502. doi:10.1890/03-0391Sheldon, J. K., & MacLeod, E. G. (1971). Studies on the Biology of the Chrysopidae II. The Feeding Behavior of the Adult of Chrysopa carnea (Neuroptera). Psyche: A Journal of Entomology, 78(2), 107-121. doi:10.1155/1971/505909Stelzl, M., & Devetak, D. (1999). Neuroptera in agricultural ecosystems. Agriculture, Ecosystems & Environment, 74(1-3), 305-321. doi:10.1016/s0167-8809(99)00040-7STEPPUHN, A., & WACKERS, F. L. (2004). HPLC sugar analysis reveals the nutritional state and the feeding history of parasitoids. Functional Ecology, 18(6), 812-819. doi:10.1111/j.0269-8463.2004.00920.xStyrsky, J. D., & Eubanks, M. D. (2006). Ecological consequences of interactions between ants and honeydew-producing insects. Proceedings of the Royal Society B: Biological Sciences, 274(1607), 151-164. doi:10.1098/rspb.2006.3701Tena, A., Hoddle, C. D., & Hoddle, M. S. (2013). Competition between honeydew producers in an ant–hemipteran interaction may enhance biological control of an invasive pest. Bulletin of Entomological Research, 103(6), 714-723. doi:10.1017/s000748531300045xTena, A., Llácer, E., & Urbaneja, A. (2013). Biological control of a non-honeydew producer mediated by a distinct hierarchy of honeydew quality. Biological Control, 67(2), 117-122. doi:10.1016/j.biocontrol.2013.07.018TENA, A., PEKAS, A., WÄCKERS, F. L., & URBANEJA, A. (2013). Energy reserves of parasitoids depend on honeydew from non-hosts. Ecological Entomology, 38(3), 278-289. doi:10.1111/een.12018Tena, A., Pekas, A., Cano, D., Wäckers, F. L., & Urbaneja, A. (2015). Sugar provisioning maximizes the biocontrol service of parasitoids. 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    The Social Relations Approach, empowerment and women factory workers in Malaysia

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    This article discusses the empowerment of women factory workers in Malaysia through the lens of Kabeer’s Social Relations Approach. The approach offers an institutional analysis of how gender inequality is produced and calls for the overall terms of exchange and cooperation to be shifted in women’s favour. Its application shows that Malaysian women factory workers face significant challenges, due to the character of institutions, and women’s difficulties in adopting and internalising the notion of ‘empowerment’

    The potential of parasitoid Hymenoptera as bioindicators of arthropod diversity in agricultural grasslands

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    1. As measuring biodiversity in its entirety is impractical, there is a need for bioindicators. This study tested the hypothesis that parasitoid Hymenoptera are potential bioindicators that provide a useful means to assess the wider biodiversity of arthropod populations in agro-ecosystems. There are a range of theoretical arguments to support such a claim, including the high trophic position of these taxa within the arthropod communities in which they occur, and the unique nature of their biological relationships with the majority of terrestrial arthropod groups. 2. A survey of 48 commercial farms was conducted and Generalized Linear Models used to investigate relationships between six taxa—parasitoid Hymenoptera, Coleoptera, Hemiptera, Diptera, Araneae and plants (species richness and sward height)—in agricultural grasslands. As well as relationships between these groups, the relationship of each individual group to the overall biodiversity of all other arthropod groups was explored. 3. Both abundance (r2 = 0·58) and taxon richness (r2 = 0·54) of parasitoid Hymenoptera had stronger relationships with overall arthropod taxon richness than any other arthropod group investigated. Parasitoid abundance also had a positive relationship with species richness of Coleoptera (r2 = 0·23) and Hemiptera (r2 = 0·47). 4. An historical data set demonstrated how the relationship between parasitoid abundance and overall arthropod taxon richness changes over the growing season. July, when the relationship was strongest, is potentially the most useful time to sample. 5. For use in routine monitoring, it is important that an effort be made to understand the seasonal influence on the relationship in the context being studied. Equal sampling effort must be made for all sites being compared and sites should be sampled as close together in the season as is possible. 6. Synthesis and applications. We show that, within agricultural grasslands, both the abundance and taxon richness of parasitoid Hymenoptera are more closely related with overall arthropod diversity than any other arthropod group investigated. The use of parasitoid abundance provides a simple and practicable monitoring tool for tracking change in wider arthropod diversity in agro-ecosystems

    Umsetzung der deutschen Approbationsordnung 2002 im modularen Reformstudiengang Heidelberger Curriculum Medicinale (HeiCuMed)

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    Am 1.10.2003 trat die neue deutsche Approbationsordnung für Ärzte (ÄAppO) in Kraft. Das klinische Lehrangebot sollte dabei in 22 Fächern, 12 Querschnittsbereichen und 5 Blockpraktika angeboten werden. Bereits 1998 begann die medizinische Fakultät der Universität Heidelberg das medizinische Curriculum stärker praktisch und interdisziplinär auszurichten. Dieses neue Curriculum erhielt den Namen HeiCuMed (Heidelberger Curriculum Medicinale). Planung und Organisation von HeiCuMed erfolgte in Kooperation mit verschiedenen universitären und auswärtigen Partnern. Dieser Artikel befasst sich mit der Umsetzung der neuen ÄAppO in HeiCuMed. Dabei wird auch dargestellt, inwiefern in der Literatur beschriebene Prinzipien erfolgreicher Curriculumsreform im Reformprozess beachtet wurden. 09.12.2008 | Sören Huwendiek, M. Kadmon, J. Jünger, M. Kirschfink, H.M. Bosse & F. Resc

    Selective Release of MicroRNA Species from Normal and Malignant Mammary Epithelial Cells

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    MicroRNAs (miRNAs) in body fluids are candidate diagnostics for a variety of conditions and diseases, including breast cancer. One premise for using extracellular miRNAs to diagnose disease is the notion that the abundance of the miRNAs in body fluids reflects their abundance in the abnormal cells causing the disease. As a result, the search for such diagnostics in body fluids has focused on miRNAs that are abundant in the cells of origin. Here we report that released miRNAs do not necessarily reflect the abundance of miRNA in the cell of origin. We find that release of miRNAs from cells into blood, milk and ductal fluids is selective and that the selection of released miRNAs may correlate with malignancy. In particular, the bulk of miR-451 and miR-1246 produced by malignant mammary epithelial cells was released, but the majority of these miRNAs produced by non-malignant mammary epithelial cells was retained. Our findings suggest the existence of a cellular selection mechanism for miRNA release and indicate that the extracellular and cellular miRNA profiles differ. This selective release of miRNAs is an important consideration for the identification of circulating miRNAs as biomarkers of disease

    How variation in head pitch could affect image matching algorithms for ant navigation

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    Desert ants are a model system for animal navigation, using visual memory to follow long routes across both sparse and cluttered environments. Most accounts of this behaviour assume retinotopic image matching, e.g. recovering heading direction by finding a minimum in the image difference function as the viewpoint rotates. But most models neglect the potential image distortion that could result from unstable head motion. We report that for ants running across a short section of natural substrate, the head pitch varies substantially: by over 20 degrees with no load; and 60 degrees when carrying a large food item. There is no evidence of head stabilisation. Using a realistic simulation of the ant’s visual world, we demonstrate that this range of head pitch significantly degrades image matching. The effect of pitch variation can be ameliorated by a memory bank of densely sampled along a route so that an image sufficiently similar in pitch and location is available for comparison. However, with large pitch disturbance, inappropriate memories sampled at distant locations are often recalled and navigation along a route can be adversely affected. Ignoring images obtained at extreme pitches, or averaging images over several pitches, does not significantly improve performance

    p-Glycoprotein ABCB5 and YB-1 expression plays a role in increased heterogeneity of breast cancer cells: correlations with cell fusion and doxorubicin resistance

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    <p>Abstract</p> <p>Background</p> <p>Cancer cells recurrently develop into acquired resistance to the administered drugs. The iatrogenic mechanisms of induced chemotherapy-resistance remain elusive and the degree of drug resistance did not exclusively correlate with reductions of drug accumulation, suggesting that drug resistance may involve additional mechanisms. Our aim is to define the potential targets, that makes drug-sensitive MCF-7 breast cancer cells turn to drug-resistant, for the anti-cancer drug development against drug resistant breast cancer cells.</p> <p>Methods</p> <p>Doxorubicin resistant human breast MCF-7 clones were generated. The doxorubicin-induced cell fusion events were examined. Heterokaryons were identified and sorted by FACS. In the development of doxorubicin resistance, cell-fusion associated genes, from the previous results of microarray, were verified using dot blot array and quantitative RT-PCR. The doxorubicin-induced expression patterns of pro-survival and pro-apoptotic genes were validated.</p> <p>Results</p> <p>YB-1 and ABCB5 were up regulated in the doxorubicin treated MCF-7 cells that resulted in certain degree of genomic instability that accompanied by the drug resistance phenotype. Cell fusion increased diversity within the cell population and doxorubicin resistant MCF-7 cells emerged probably through clonal selection. Most of the drug resistant hybrid cells were anchorage independent. But some of the anchorage dependent MCF-7 cells exhibited several unique morphological appearances suggesting minor population of the fused cells maybe de-differentiated and have progenitor cell like characteristics.</p> <p>Conclusion</p> <p>Our work provides valuable insight into the drug induced cell fusion event and outcome, and suggests YB-1, GST, ABCB5 and ERK3 could be potential targets for the anti-cancer drug development against drug resistant breast cancer cells. Especially, the ERK-3 serine/threonine kinase is specifically up-regulated in the resistant cells and known to be susceptible to synthetic antagonists.</p

    Abundance, movements and biodiversity of flying predatory insects in crop and non-crop agroecosystems

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    [EN] Predatory insects are key natural enemies that can highly reduce crops pest damage. However, there is a lack of knowledge about the movements of flying predatory insects in agroecosystems throughout the year. In particular, it is still unclear how these predators move from crop to non-crop habitats, which are the preferred habitats to overwinter and to spread during the spring and if these predators leave or stay after chemical treatments. Here, the Neuroptera, a generalist, highly mobile, flying predator order of insects, was selected as model. We studied the effects of farming management and the efficiency of edge shelterbelts, ground cover vegetation, and fruit trees canopy on holding flying predatory insects in Mediterranean traditional agroecosystems. Seasonal movements and winter effects were also assessed. We evaluated monthly nine fruit agroecosystems, six organic, and three pesticides sprayed, of 0.5-1 ha in eastern Spain during 3 years using two complementary methods, yellow sticky traps and aspirator. Results show surprisingly that the insect abundance was highest in pesticide sprayed systems, with 3.40 insects/sample versus 2.32 insects/sample in organic systems. The biodiversity indices were highest in agroecosystems conducted under organic management, with S of 4.68 and D of 2.34. Shelterbelts showed highest biodiversity indices, S of 3.27 and D of 1.93, among insect habitats. Insect species whose adults were active during the winter preferred fruit trees to spend all year round. However, numerous species moved from fruit trees to shelterbelts to overwinter and dispersed into the orchard during the following spring. The ground cover vegetation showed statistically much lower attractiveness for flying predatory insects than other habitats. 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