Growth and Development in Parasitoid Wasps: Adaptation to Variable Host Resources

Abstract

Fitness returns to a female parasitoid depend on how she distributes offspring over available hosts and host patches (reviewed in Godfray 1994), and on how immature parasitoids adapt to variation in host resources. The kind and the amount of resources provided by the host determine its quality for parasitoid survival and development (Mackauer and Sequeira 1993). In idiobionts, species that develop in non-feeding host stages such as eggs and pupae, the host represents a “closed” system. The amount of available resources depends on host size, which can be assessed by the female at oviposition, regardless of any physiological changes that may occur later during the interaction (Strand 1986; King 1990). In contrast, koinobionts exploit hosts that continue to feed, grow and metamorphose after parasitization; the host represents an “open” system. Because quality is determined by the host’s nutrition and growth potential after parasitization, which vary with circumstances during the interaction (Sequeira and Mackauer 1992a, 1994), it cannot be evaluated from age and size differences alone.