THE EFFECT OF SUPERPARASITISM ON DEVELOPMENT OF THE SOLITARY PARASITOID WASP, VENTURIA-CANESCENS (HYMENOPTERA, ICHNEUMONIDAE)

1. The effects of superparasitism on the rate of development, adult size and mortality of Venturia canescens (Hymenoptera: Ichneumonidae) were investigated. Parasitoids were reared from third (L3) and fifth (L5) instars of one of its hosts, Plodia interpunctella (Lepidoptera: Pyralidae) containing one, two or four parasitoid eggs. 2. Superparasitism increased the development time of Venturia reared from both instars, but the developmental delay was more evident in wasps from L5 hosts. 3. The size of parasitoids from L3 hosts was unaffected by egg number, but wasps from both superparasitized L5 treatments were significantly smaller than those from singly parasitized hosts. 4. Parasitoid mortality was significantly higher in L5 than L3, but within instars did not differ significantly with egg number. 5. The results confirm that superparasitism may affect the fitness of both the adult female wasp and her progeny, and should therefore be incorporated into models of superparasitism as an adaptive foraging strategy.