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Combining stable isotopes analyses with next generation sequencing to disentangle trophic links in banana agroecosystem

Tixier P., Lescourret F., Guenifi S., Martin J.F., Duyck P.F.. 2011. Reno : s.n., 1 p.. Entomology 2011. 59, 2011-11-13/2011-11-16, Reno (Etats-Unis).

Bottom-up and top-down effects are recognized to be important mechanisms structuring foodwebin ecosystems. A new resource added to an agroecosystem, as a cover crop, may supportalternative preys which affect feeding behavior of generalist predators and natural regulationof pests. We studied the effect of adding a cover crop, Brachiaria decumbens, on the diet ofherbivores and predators in a banana agroecosystem in order to emphasize interactions of amajor pest, Cosmopolites sordidus, with other species of the system. We used stable isotopesanalysis (C and N) to determine trophic levels and origin of carbon consumed, and molecularmarkers (shortened region of trnL chloroplastic marker for plants, and CO1 mitochondrialgene for arthropods) to decipher qualitative composition of gut contents of each species. Weshowed that diet of herbivores and predators are modified by the addition of the new basalresource. This has consequences for the predation of the pest. This dual approach allowed usto build an almost complete food-web of banana agroecosystem that is a starting point to model these interactions and design cropping system maintaining low occurrence of pests (texte intégral)

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