Does male behavioral type correlate with species recognition and stress?

Abstract

The persistence of gynogenetic organisms is an evolutionary paradox. An ideal system for examining the persistence of gynogens is the unisexual–bisexual mating complex of the unisexual Amazon molly (Poecilia formosa), and the bisexual, parent species, the sailfin molly (Poecilia latipinna) and the Atlantic molly (Poecilia mexicana). Insight into the maintenance of this mating complex might be enhanced by taking a more holistic view of male and female behavior through a behavioral syndrome framework. In this study, we examined whether male mate choice is part of a behavioral syndrome. We quantified behaviors related to activity, boldness, exploration, and sociability in male sailfin mollies, as well as their mate preference for conspecific females or the all-female species of Amazon mollies. In addition, we explored the relationship between behavioral type and cortisol (a fish stress hormone) production in male sailfin mollies. We found evidence for behavioral correlations in male sailfin mollies, but individual behavioral type was not correlated with their mate preference or stress hormone production. However, we did find differences in preexperience cortisol production related to male boldness behaviors. The lack of correlation between behavioral types, mate preference, and stress hormone production emphasizes that the nature of behavioral–hormonal interactions is complex. In summary, neither individual traits nor the behavioral types found here are adequate to explain the maintenance of this unisexual–bisexual mating system.