Egg size variation does not affect offspring performance under intraspecific competition in Nasonia vitripennis, a gregarious parasitoid

Abstract

1. As with many insects, egg size variation is correlated with body size in the gregarious parasitoid, Nasonia vitripennis. I use this feature to test the hypothesis that egg size differences among parents affects the ability of their larvae to compete for limited resources within a superparasitized host. 2. I show that egg size asymmetries in parents that oviposit into the same host have no detectable effect on relative offspring performance, even under conditions of resource limitation. 3. Broods within a host that were initiated earlier attained greater average size than competing broods in the same host that were initiated later. 4. Individuals in the more numerous brood emerged consistently larger than individuals in the less numerous brood. 5. The possibility that siblings cooperate in competing for limited resources within a host and the potential role of sibling cooperation on egg size evolution is discussed. © 2005 British Ecological Society.