Variation in fighting strategies in male wing-dimorphic crickets (Gryllidae)

Abstract

Because a trade-off between reproduction and dispersal has been commonly found in wing-dimorphic insects, males of different wing morphs may have a different demand on a mate or a territory. We hypothesized that males of wing-dimorphic insects may vary in fighting success over these two resources. To test this hypothesis, we compared morphological traits linked to fighting ability between long-winged (LW) and short-winged (SW) male Velarifictorus aspersus crickets (Gryllidae) and investigated their fighting success over a burrow or a mate. SW males gained more biomass than did LW males after molting to adulthood, indicating that morphological traits that can influence fighting ability differed between wing-dimorphic male crickets (Gryllidae). SW males won significantly more fights than did LW males when fighting for a mate. However, LW males were more aggressive than SW males when intruding the burrow of another male, and the winning probability of LW intruders was significantly greater than that of SW defenders. Fighting outcome significantly influenced the ownership of resources, and winning could help crickets (Gryllidae) become more successful in acquisition of the target resource. Our results suggested that trade-offs between life-history traits result in the differentiation of fighting strategies, such that both winged forms could succeed with their particular life-history strategy.