Supplementary nutrient sources improve biological performance of Gonatopus bonaerensis (Hymenoptera: Dryinidae), decreasing unwanted destructive host-feeding

Abstract

In this study, the effects of different food sources were tested on the longevity, fecundity, host-feeding and parasitism rates of Gonatopus bonaerensis Virla (pincer wasp) using the planthopper Delphacodes sitarea Remes Lenicov & Tesón as host. Marked differences were verified in longevity, fecundity, host-feeding and parasitism levels when the diet of females was supplemented with pollen, bee honey, or with honey + vitamin E. The addition of pollen to the diet significantly increased the longevity of females. In concordance with the record of a greater number of eggs laid throughout their lives, pincer wasp females provided with nymphs + honey + vitamin E parasitized significantly more host nymphs and carried out fewer host-feeding activities than those maintained under other diets. When females had access to supplementary food sources, the concurrent host-feeding decreased, increasing the effectiveness of this pincer wasp. Even though a good number of hosts were healthy after the exposure period, greater phenomena of self-superparasitism were recorded in females that received alternative food sources. Relevance of different food sources for enhancing parasitoid performance and the potential benefits for artificial rearing and field releases are discussed.