Host stage affects oviposition-related behaviours, development progression and reproductive output in a native hyperparasitoid of the solenopsis mealybug invading Asian regions

ABSTRACT Native hyperparasitoids may readily expand their host range by including non-native parasitoids that are introduced in classical biological control of pest insects. Here we report our observation on biology of Cheiloneurus nankingensis (Hymenoptera: Encyrtidae), an obligate hyperparasitoid attacking non-native parasitoid Aenasius arizonensis residing in Phenacoccus solenopsis mealybugs that have invaded into Asian regions. We measured durations of antennae-tapping, ovipositor-drilling and ovipositor-probing/ovipositing behaviours by C. nankingensis wasps on parasitised mealybugs with the host at either larval or pupal stage and on the unparasitised mealybug as the control. The ovipositor-probing/ovipositing duration was much longer on a pupal host than on the larval while shortest on the control. We then observed offspring development progression of C. nankingensis at attacking either egg, larva or pupa of its host by daily dissecting hyperparasitised mealybugs. The development was faster in a larval or pupal host than in the egg. Finally, our measurements of the reproductive output showed that C. nankingensis wasps during 14 days after the emergence attacked more parasitised mealybugs and produced more offspring reaching adulthood when ovipositing in the mealybug with a host larva than with a pupa. Our results from this study suggest that C. nankingensis may employ the ovipositor to probe for the host within a mealybug and the host at the larval stage is of high quality for the reproduction.