Non-reproductive host killing caused by Aphelinus asychis (Hymenoptera: Aphelinidae), a parasitoid of cotton aphid, Aphis gossypii (Homoptera: Aphididae)

Abstract

Aphelinus asychis Walker (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that parasitizes and host-feeds more than 40 aphid species, and has been considered a potential biological control agent of aphids. In many species of hymenopterous parasitoid, female wasps cause important additional mortality by non-reproductive killing (e.g., host-feeding and stinging behaviour). Host mortality caused by nonreproductive host killing of A asychis was studied on cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae) when infesting cucumber (Cucumis sativus L.), in the laboratory at 25 °C and photoperiod of 16L: 8D. The females killed 3.3 aphids per day and 73.9 aphids until they died by host-feeding and stinging during an average of 21.3 days. Peak age-specific aphid mortality (5.2 aphids per day) was observed on the fifth day after parasitoid emergence. A. asychis females continued non-reproductive host killing until died.