Neutral fitness outcomes contradict inferences of sexual 'coercion' derived from male's damaging mating tactic in a widow spider.

摘要: Sexual conflict over mating frequency has driven the evolution of morphological and behavioural traits across taxa. Interactions may be termed ‘coercive’ assumed to arise from when male behaviours cause physical injury females appear resist injurious matings.However, coercion per se occurs only if behaviour reduces female fitness; and such outcomes are rarely measured. Here we show that a damaging tactic, apparently adaptive for males, is not coercive females. Adult Latrodectus spiders mate with immature after tearing exoskeleton covering female’s recently-developed reproductive tract, which can haemolymph bleeding. We that, relative pairings adult females, males use reduced courtship displays approaching in some cases respond elevated deterrent responses. Nevertheless, found no cost immature-mated terms longevity, fertility or fecundity. Moreover, most did produce sex pheromones as adults, so seek additional matings. Thus, despite appearance there evidence immature-mating coercive. These results it critical measure fitness outcomes, addition responses, test coercion.