Salivary α-Amylase of Stem Borer Hosts Determines Host Recognition and Acceptance for Oviposition by Cotesia spp. (Hymenoptera, Braconidae)

Abstract

Foraging insect parasitoids use specific chemical cues to discriminate between host and non-host species. Several compounds have been identified in "host location and acceptance." However, nothing is known about the molecular variations in these compounds that could account for host-range differences between parasitoid species. In a previous study, it was shown that during the host-finding process, contact between the braconid Cotesia flavipes and its host is crucial, and that α-amylase of oral secretions from the host plays a key role for host acceptance and oviposition by the parasitoid. The present study sought to establish whether the variations in this enzyme could explain specific host recognition in different host-parasitoid associations. Different species and populations of the C. flavipes complex specialized on graminaceous lepidopteran stemborers were used. Electrophoresis of α-amylase revealed different isoforms that mediate the parasitoid's oviposition acceptance and preference for a specific host. This discovery opens up new avenues for investigating the evolutionary processes at play in chemically-mediated host specialization in the species-rich Cotesia genus.

Impact of the exotic fall armyworm on larval parasitoids associated with the lepidopteran maize stemborers in Kenya

“…On the other hand, C. typhae did not attack any instar of the host. This might be due to the higher host specificity of this parasitoid, which has been previously documented (Kaiser et al 2017;Bichang'a et al 2018). Host habitat specificity could also play a key role in the behaviour of the four parasitoids in terms of their attraction to and attacks on FAW larvae.…”