Longevity and fecundity of the egg parasitoid Telenomus podisi provided with different carbohydrate diets

Abstract

In order for successful biological pest control using parasitoids, the most suitable naturally available food resources, as well as the fitness of parasitoids feeding on these resources, need to be ascertained. The goal of this study was to improve the understanding of the ecological requirements and consequent fitness of one such parasitoid, Telenomus podisi Ashmead (Hymenoptera: Platygastridae), a predominant stink bug (Heteroptera: Pentatomidae) egg parasitoid native to southeastern USA. We assessed the effects of carbohydrate resources readily available in the wasp's natural habitat on longevity and fecundity of female T. podisi under laboratory conditions. Carbohydrate diets included in the study were buckwheat, Fagopyrum esculentum Moench (Polygonaceae) nectar and honeydew from cowpea aphid, Aphis craccivora Koch (Hemiptera: Aphididae), compared with honey or water controls, which are normally used for laboratory rearing of this species. Eggs of Podisus maculiventris Say (Hemiptera: Pentatomidae) were provided as hosts for oviposition. Honeydew of cowpea aphid proved to be as good a nutrition source as buckwheat nectar, in enhancing wasp longevity and fecundity. We also assessed the importance of honeydew freshness on the biological attributes of T. podisi, as honeydew becomes crystallized or highly viscous on drying up and therefore may pose an issue for uptake by parasitoids. We found that fresh honeydew of the pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae) significantly enhanced wasp longevity when compared to a diet of 1-day-old honeydew and the fava bean leaf (control). However, fresh honeydew of green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae) had the same effect on wasp longevity, fecundity, and proportion of male progeny as radish leaf (control). The potential of certain ubiquitously available food resources, in enhancing biological control of economically damaging pests by parasitoids, is being highlighted in this study; information which could be valuable in similar parasitoid-host systems as well.