Behaviour and fitness impacts of irradiation-induced sterility in an egg parasitoid and potential implications for their use for insect eradication

Abstract

AbstractAs the increasing globalisation of trade generates an escalating spread of arthropod pests, eradication has gained traction as a viable approach to avoiding the growing long-term management costs. The Sterile Insect Technique (SIT) involves releasing sexually sterile insects into the wild population and has been employed for environmentally friendly eradication. Alternatively, classical biological control (CBC) comprises the importation and release of natural enemies. Although generally used for long-term management, evidence suggests a synergistic impact could be exerted on pest populations when combined with SIT, potentially improving eradication outcomes. It is possible that sterile parasitoids, which would not bear the risk of irreversible non-target impacts associated with conventional CBC releases, could be accepted by regulatory agencies as a safe option to be used as a synergistic component of eradication. We investigated the post-irradiation behaviour and fitness of the egg parasitoid Trissolcus basalis to determine whether irradiation-induced sterility may reduce its efficacy. In comparing sterile and non-sterile parasitoids, there were no observable differences in searching behaviour, no significant differences in the number of egg masses found and parasitised, nor longevity. It is possible that sterile parasitoid release could contribute to an eradication programme without detrimental effects.