No male agonistic experience effect on pre-copulatory mate choice in female earwigs

Abstract

Mating with dominant males may confer consid- erable benefits, but also incur significant costs, hence intrasexual competitiveness is a likely target of mate choice. In addition to established modes of mate assessment, females may use cues or signals associated with agonistic experience effects to assess the relative competiveness of males. Experience effects, where the outcome of a fight increases the likelihood of a similar outcome in subsequent fights, may result from an animal's altered state after con- flict, but can also arise from strategic rival use of informa- tion perceived about this altered state. While females may similarly use this information in mate choice decisions, this potential consequence of male-male conflict has largely been neglected. Here, we investigate the effects of ex- perience on subsequent agonistic performance in the earwig Euborellia brunneri by imposing winning or losing ex- periences on males and rematching them with naive, size- matched rivals. We reveal a strong loser effect in subsequent fights, with nearly all previous "losers" losing against new rivals. In contrast, we found no equivalent winner effect, with previous "winners" exhibiting no increased likelihood of winning. We subsequently test whether the effects of male agonistic experience extend to pre-copulatory female mate choice. We show that females, when allowed to choose between naive males and "winners" or "losers", do not discriminate between males based on their recent agonistic experience. Therefore, while fighting history can play an important role in male-male interactions, females may not attend to this information.