Oviposition site selection by the predatory midge Aphidoletes aphidimyza (Diptera : Cecidomyiidae)

Eggs and neonate larvae of the aphidophagous midge Aphidoletes aphidimyza R ondani are vulnerable to intraguild predation and starvation. The role of A . aphidimyza females in selecting suitable oviposition sites for offspring survival and development was investigated in the laboratory on potato. Ovip osition preference, measured as the number of eggs laid in different microh abitats, increased with density of the potato aphid. Macrosiphum euphorbiae (Thomas), and plant pubescence, However, midge females do not discriminate between plants colonized by the coccinellid predator Coleomegilla maculata lengi Timberlake and those that are not. A. aphidimyza egg survival in the presence of C. macula larvae and adults was higher in sites characterized by a high density of trichomes than in other microhabitats. The selection o f pubescent leaves infested with aphids by ovipositing females reflects bot h the food dependence and predation risk constraints of immature midges.