Male Mating Strategies within a Shifting Competitive Landscape: Performance and Phenotypic Correlates of Mate Guarding Success

Mate-guarding males who limit access of rivals to females may be likewise preferred by females, or their mating advantage may lie only in excluding opponents. In the jumping spider Phidippus clarus, males guard immature females, mating once females synchronously moult. To investigate factors contributing to mate guarding success in the field, we compared the morphology, competitive and courtship success of guarding and non-guarding males collected throughout their season. Guarders were larger than roamers only during the time when females moult, and also demonstrated both higher fighting and courtship success independent of size-related advantages. Thus, high levels of male-male competition during female moult implicates male-male contests in determining mate-guarding success. Given the proposed significance of mate guarding to male fitness, heritability of traits related to competitive ability and guarding may explain the observed correspondence between sexual selection via female choice and male-male competition.