Does oligophagy in herbivores promote diet specialization at the higher trophic level?
عنوان دوره: اولین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
Plant mediated effects always have had an important role in prey-predator interaction. Many wild plants contain higher level of defense compound than their domesticated congeners and specialized herbivores can often utilize those toxins to compile their own chemical arsenal to escape enemies. Contrary to specialist herbivore, generalist herbivores don't have an evolved special adaptation to detoxify and sequester plant secondary metabolites and consequently can't benefit of those against their natural enemies. Objective of the present study was to investigate the effect of two different prey type, include specialist herbivore Brevicoryne brassicae L. (Hem.: Aphididae) and generalist one, Myzus persicae Sulzer .(Hem.: Aphididae) when fed on black mustard (Brassica nigra), a wild species with high levels of sinigrin, on the performance of the generalist aphidophagous Episyrphus balteatus De Geer (Dip.: Syrphidae). Sinigrin was quantified by HPLC in both leaf samples and total aphid bodies reared on the black mustard. The individual fitness of the predator on these aphids when fed on generalist prey was clearly better than when fed on specialist one. Also Females had a higher overall preference for the generalist aphid with relatively low levels of sinigrin than specialist one with high levels of the toxin. Our finding show that oligophagous herbivores may due to co-opt toxicity from their host plants induce an specialization at the higher trophic level toward polyphagous herbivores.
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