Mate choice in white and common threespine sticklebacks (gasterosteus aculeatus)

Abstract

During speciation, mate choice can reproductively isolate one group from another through selection on divergent traits and behaviours such as colouration, courtship behaviour, and/or body size. Reinforcement can also limit interbreeding between ecotypes in sympatric populations through these sexually selected traits. The primary goal of this research was to investigate male mate choice in common and white Threespine Sticklebacks <i>(Gasterosteus aculeatus)</i> that are known to mate assortatively in sympatric populations and who differ markedly in their propensity for paternal care. I observed mate choice of both male and female sticklebacks from sympatric and allopatric populations. Neither common nor white male stickleback courted or mated assortatively. Additionally, female stickleback did not differ in their responses to males of either ecotype. Our research suggests that there is no ecotype-based preference for white and common Threespine Sticklebacks and that mechanisms other than reinforcement may be responsible for the maintenance of common and white Threespine Stickleback ecotypes.