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Mutual interference reduces offspring production in a brood‐guarding bethylid wasp

Sreenivas, A.G., Hardy, Ian C.W.
Entomologia experimentalis et applicata 2016 v.159 no.2 pp. 260-269
Goniozus, arthropod pests, biological control, brood rearing, females, foraging, hosts, mass rearing, parasitoids, pest control, progeny
Parasitoids have the potential to suppress populations of their hosts and thus may play an important role in influencing the temporal and spatial dynamics of pest arthropods. Behavioural interactions between foraging females, collectively constituting ‘mutual interference’, can reduce host suppression. We use laboratory microcosms to assess the prevalence and consequences of mutual interference behaviour in a bethylid wasp, Goniozus nephantidis (Muesebeck) (Hymenoptera: Bethylidae), which is known to brood guard and to engage in agonistic contests for individual hosts and which is also an agent of biological pest control. We hold host and parasitoid numbers constant and vary the degree of female–female contact that can occur. Mutual interference is manifest in a considerable reduction in the number of offspring produced when females are not fully isolated from each other, due to effects operating at the early stages of offspring production. This mutual interference may contribute towards the limited degree of host population suppression achieved when some species of bethylids are deployed as agents of biological pest control and also has clear potential to influence the efficiency of mass rearing of parasitoids prior to field release.