Mating status of an autoparasitoid and sex of the secondary host impact the outcome of heteronomous hyperparasitism

Description

Autoparasitoids are important biocontrol agents for controlling hemipteran pests. Females of these wasps lay fertilized eggs in whitefly nymphs (primary host) which develop as females. The males develop as hyperparasitoids from unfertilized eggs on conspecific or other primary parasitoid species (as secondary hosts). To date, the effects of mating and secondary host sex on hyperparasitism have been largely neglected. We studied heteronomous hyperparasitism of mated and unmated Encarsia sophia (Girault & Dodd) (Hymenoptera: Aphelinidae) females on different secondary hosts (conspecific or heterospecific: Eretmocerus hayati Zolnerowich & Rose (Hymenoptera: Aphelinidae)) in no-choice and paired-choice bioassays. We demonstrated that regardless of their mating status E. sophia females were unable to parasitize male secondary hosts. Although mating of E. sophia females had no effect on the number of parasitized conspecific females, the number of heterospecific females (E. hayati) parasitized by mated E. sophia was greater than in the unmated females. The mating status of E. sophia females had no effect on host feeding on conspecific secondary hosts, but it did increase host feeding on hetero-specific secondary hosts (E. hayati). In no-choice bioassays, both mated and unmated E. sophia females preferred E. sophia third instar female larvae and one-day-old E. hayati female pupae as their hosts, and preferred to feed on E. sophia third instar female larvae. In paired-choice bioassays, E. sophia females preferred to feed on E. hayati male pupae over female pupae, and consumed more E. sophia female pupae than male pupae regardless of mating status. Our results suggest that mating status modulates parasitism and host feeding of E. sophia females on heterospecific secondary hosts. In addition, we demon-strated that E. sophia females are unable to parasitize secondary male hosts to produce E. sophia males.

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