Impact of host behavioral defenses on parasitization efficacy of a larval and adult parasitoid

Koinobiont parasitoid females when attacking host species are faced with barriers at various levels, host behavioral defenses represent one of these barriers. We present data of the effects of host behavioral defenses on host preference of larval and adult parasitoid. We quantified the effects of defensive behaviors of the exotic host, Harmonia axyridis (Pallas), and the indigenous host, Coleomegilla maculata lengi Timberlake (Coleoptera: Coccinellidae), on the handling time and attack preference of the indigenous parasitoid, Dinocampus coccinellae Schrank (Hymenoptera: Braconidae). Successful egg development was also recorded as a consequence of host behavioral defense and unsuitability. Female parasitoids were offered in an interspecific choice test, adult or larvae of both H. axyridis and C. maculata, and in an intraspecific choice test, larval and adult stage of H. axyridis. Adult H. axyridis exhibited a greater number of defensive behaviors compared to adult C. maculata or larval H. axyridis resulting in significantly longer handling time by the parasitoid. Our results suggest that host acceptance cues used by the generalist parasitoid D. coccinellae are inadequate to evaluate adult H. axyridis. These results provide support to the hypothesis that H. axyridis represents an evolutionary trap for D. coccinellae.