Early social experience, rather than kinship affecting aggression in an egg parasitoid wasp, Anastatus disparis (Hymenoptera: Eupelmidae), that exhibits extreme male–male combat behaviour

Abstract

Fighting behaviour is important for acquiring crucial resources and is widely observed in the animal kingdom. Based on the conflict consequence, fighting behaviour is usually classified into non-extreme and extreme fighting patterns. Numerous factors that influence aggression, such as resource value, resource-holding potential, kinship, and prior experience, have been extensively studied, resulting in the emergence of many important theories. To secure mating opportunities, males of the quasi-gregarious parasitoid, Anastatus disparis (Hymenoptera: Eupelmidae), exhibit extreme fighting behaviour. Inconsistent with the general kin selection theory prediction, there is no evidence that male A. disparis competitors alter their fighting behaviour in response to relatedness with resource presence or interacted with altering resource value. The results of our current study do not clearly indicate whether unchanged kin-based aggression is caused by a lack of kin recognition ability or overriding by competition for resources, which A. disparis males rarely exhibit fighting behaviour under condition of resource female absence in the environment. However, significant decreases in the fighting frequency and intensity in A. disparis were shown in males with early social experience, which was also not influenced by the kinship between the contestants. Our result suggests that in A. disparis, male aggression was likely mediated by early social experience rather than kinship.