Host Suitability for Insect Parasitoids

Abstract

The parasitic mode of life is very productive and has evolved in numerous orders of arthropods. Many parasitic insects differ from other parasitic organisms in that the adults of parasitic insects are free living, a limited number of progeny develop per host, and the host does not survive the encounter. These parasitic insects have been referred to as parasitoids to distinguish them from other parasitic organisms in which the adults and their progeny are parasitic, many individuals of different generations may occur on the same host, and the host is usually not killed. Unlike the parasite-host relationship, the evolution of the parasitoid-host relationship is of little consequence for the host, which does not survive the association to pass on its genetic information (203). The coevolution of the parasitoid and host has resulted in a number of unique associations. There are a number of steps necessary for the success of the parasitoid­ host relationship. Doutt (44) divided the events into four steps: (a) host habitat location, (b ) host location, (c) host acceptance, and (d ) host suit­ ability. Vinson (203) added a fifth step, referred to as host regulation. Whether a parasitoid is able to develop within a host may depend on the ability or inability of the parasitoid to regulate the host's physiology. The