Responses of aphidophagous syrphids toward oviposition site quality
عنوان دوره: اولین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
The oviposition site selection by aphidophagous insects is complex because of tritrophic interactions among host plant, aphid and natural enemies. Decision making for oviposition by females regarding oviposition site is more important for the insects by limited dispersal ability, such as most aphidophagus insects. Several factors are known to affect the find suitable oviposition site by aphidophagous syrphids. In this study we focused on the oviposition responses of two generalist aphidophagous syrphids (Eupeodes luniger Meigen and Episyrphus balteatus De Geer) towards host plant-aphid combinations differing in sinigrin content and the presence of intra- and inter-specific competitors. Sinigrin was quantified by HPLC in both leaf samples and total aphid bodies reared on the given host plants (black mustard and canola). Oviposition responses were determined in the laboratory using females of known age.The oviposition response of E. luniger was influenced significantly by the presence of intraguild competitors and also by the sinigrin content of host plants (according to Duncan’s multiple range test at α = 0.05) . Likewise, the overall proportion of eggs laid by female E. balteatus was greater on aphids with relatively low levels of sinigrin (according to paired t-test). Our findings help in understanding the factors governing the oviposition responses of aphidophagous predators.
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