Kim Diana, Aspbury Andrea S, Zúñiga-Vega J Jaime, Gabor Caitlin R
Department of Biology, Texas State University, 601 University Drive, San Marcos, TX 78666, USA.
Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Cuidad Universitaria 04510, Distrito Federal, Mexico.
Behav Processes. 2019 Oct;167:103916. doi: 10.1016/j.beproc.2019.103916. Epub 2019 Aug 3.
Male mate discrimination may be affected by the social environment (presence or absence of rival males or mates), which can also affect stress and sex hormones (e.g., cortisol and 11-ketotestosterone (11-KT)). The Amazon molly, Poecilia formosa, is an all-female fish species dependent on sperm from mating with male P. latipinna. We investigated male mate choice in P. latipinna between conspecific females and P. formosa with a rival male present and no rival male present. We measured cortisol and 11-KT release rates from all fish. The presence of a rival male had no effect on male mate choice for conspecific females nor overall mating effort. Male 11-KT decreased on the second day after exposure to a rival male on the first day. Focal male 11-KT is positively correlated with the size of the rival male. Both conspecific and heterospecific females released more 11-KT when in the rival male treatment than when not. Neither male nor female cortisol was affected by the presence or absence of the rival male. We did not find an effect of rival males on male mate choice in contrast to our prediction. Instead, our findings may indicate a hormonal response to social competition.
雄性配偶选择可能会受到社会环境（是否存在竞争雄性或配偶）的影响，而社会环境也会影响应激和性激素（如皮质醇和11-酮睾酮（11-KT））。亚马孙帆鳉（Poecilia formosa）是一种全雌性鱼类，依赖与雄性帆鳉（P. latipinna）交配获取精子。我们研究了在有竞争雄性存在和无竞争雄性存在的情况下，雄性帆鳉对同种雌性和亚马孙帆鳉的配偶选择。我们测量了所有鱼类的皮质醇和11-KT释放率。竞争雄性的存在对雄性对同种雌性的配偶选择以及总体交配努力均无影响。在第一天接触竞争雄性后，雄性的11-KT在第二天有所下降。焦点雄性的11-KT与竞争雄性的体型呈正相关。与未处于竞争雄性处理组时相比，处于竞争雄性处理组的同种和异种雌性均释放了更多的11-KT。竞争雄性的存在与否对雄性和雌性的皮质醇均无影响。与我们的预测相反，我们未发现竞争雄性对雄性配偶选择有影响。相反，我们的研究结果可能表明了一种对社会竞争的激素反应。
