Recognition of competitive asymmetries reduces the severity of fighting in male Idarnes fig wasps

Intense sexual selection leading to male fighting in fig wasps is extensively documented and has evolved independently in several lineages of nonpollinating and pollinating fig wasps. We studied wingless males of nonpollinating Idarnes fig wasps, and observed assessment display and defensive behaviour (mating inside the female galls and sheltering within empty galls) during the mating period, in opposition to reported indications that such behaviour does not play an important role in the avoidance of fatal combats in fig wasps. Compared to males of other species with similar morphology and future reproductive opportunities, males of these species generally showed lower scores of physical injuries due to aggressive confrontations. Our results are consistent with models of asymmetric contest competition, and suggest that defensive behaviour and particular internal features of figs may increase the importance of the recognition of competitive asymmetries in reducing the severity of fighting in closed systems.