Proximate and Ultimate Perspectives on the Maintenance of a Unisexual-Bisexual Mating Complex: Importance of Behavioral Syndromes and Stress Hormones




Muraco, James J.

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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, host species, the sailfin molly (P. latipinna) and the Atlantic molly (P. 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. Studies of behavioral syndromes examine individual consistency and repeatability through time in suites of correlated behavioral traits. In this study, I examined whether male sailfin mollies (n=50) exhibited behavioral syndromes (BS) and if there was a relationship between BS and male mate preference as well as stress hormone production. Additionally, I examined whether female sailfin mollies and Amazon mollies (n=40 of each species) exhibited behavioral syndromes. Furthermore, I examined whether there were differences in BS across species, whether there was a relationship between BS and stress hormone production, and whether there was a difference in stress hormone production across species. Male sailfin mollies exhibited a BS, with multiple correlations among activity, boldness and exploration traits, as well as correlations among activity and social traits. I did not find a significant relationship between BS in males and male mate preference; however, there was a relationship between boldness and baseline cortisol production. I did not detect a significant difference in BS between female sailfin mollies or Amazon mollies, although I found a relationship between the stress response and boldness and explorative behaviors, as well as a difference in stress hormone production between species. Taken together, these results suggest that there is a proximate link between BS and stress hormones; however, the ultimate relationship between BS and the maintenance of the unisexual-bisexual mating complex is less clear.



Cortisol, Stress hormones, Mating complex, Unisexual-bisexual, Gynogenetic, Mate preference, Behavioral syndromes, Poecilia


Muraco, J. J. (2012). <i>Proximate and ultimate perspectives on the maintenance of a unisexual-bisexual mating complex: Importance of behavioral syndromes and stress hormones</i> (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


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