Egg Load and the Decision to Host-Feed in the Parasitoid, Aphytis melinus

Abstract

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Dynamical consequences of optimal host feeding on host-parasitoid population dynamics

“…These models predict existence of a threshold egg load below which host-feeding occurs. While these predictions qualitatively agree with experimental results of Collier et al (1994) who showed that probability of host-feeding declines with the egg load, a similar experiment by Rosenheim and Rosen (1992) does not show such a relationship.…”

“…On the level of individuals this trade-off leads to dynamical programming which predicts the best feeding behavior of a parasitoid. The general prediction of these models is that there is a threshold in the egg load; if the egg load is below the threshold, host-feeding appears (Collier et al 1994). However, these models do not consider population dynamics.…”

“…Since host-feeding (i. e., the consumption of host haemolymph by the adult female parasitoid) may have a major impact on host mortality, host-feeding parasitoid species may prove to be good biological control agents (Kidd and Jervis 1989). Host-feeding was also studied in the framework of dynamic state variable models (Collier et al 1994, Houston et al 1992). These models predict existence of a threshold egg load below which host-feeding occurs.…”

Lifetime allocation of juvenile and adult nutritional resources to egg production in a holometabolous insect

“…In both types of parasitoids, the decisions of the females regarding when to search for food and when to search for oviposition sites are triggered by physiological parameters. Indeed, in all the mathematical models of parasitoid behaviour developed so far, foraging decisions have been shown to be strongly dependent on the pattern of allocation of nutrients from adult food to egg production and survival (Houston et al 1992;Chan & Godfray 1993;Collier et al 1994;Heimpel et al 1994;Collier 1995a;Sirot & Bernstein 1996).…”

“…Some of the most comprehensive theoretical models of resource allocation to reproduction and survival have been developed in order to predict female reproductive behaviour in a group of insects known as parasitoid wasps (Houston et al 1992;Chan & Godfray 1993;Collier et al 1994;Godfray 1994;Heimpel et al 1994Heimpel et al , 1998Collier 1995a). These models have provided us with an unprecedented understanding of the behavioural tradeo¡s and physiological constraints faced by foraging insects.…”