Data from: Conspicuous female ornamentation and tests of male mate preference in threespine sticklebacks (Gasterosteus aculeatus)

Sexual selection drives the evolution of exaggerated male ornaments in many animal species. Female ornamentation is now acknowledged also to be common but is generally less well understood. One example is the recently documented red female throat coloration in some threespine stickleback (Gasterosteus aculeatus) populations. Although female sticklebacks often exhibit a preference for red male throat coloration, the possibility of sexual selection on female coloration has been little studied. Using sequential and simultaneous mate choice trials, we examined male mate preferences for female throat color, as well as pelvic spine color and standard length, using wild-captured threespine sticklebacks from the Little Campbell River, British Columbia. In a multivariate analysis, we found no evidence for a population-level mate preference in males, suggesting the absence of directional sexual selection on these traits arising from male mate choice. Significant variation was detected among males in their preference functions, but this appeared to arise from differences in their mean responsiveness across mating trials and not from variation in the strength (i.e., slope) of their preference, suggesting the absence of individual-level preferences as well. When presented with conspecific intruder males, male response decreased as intruder red throat coloration increased, suggesting that males can discriminate color and other aspects of phenotype in our experiment and that males may use these traits in intrasexual interactions. The results presented here are the first to explicitly address male preference for female throat color in threespine sticklebacks.性选择驱动了诸多动物物种中夸张雄性装饰物的演化。如今雌性装饰物的普遍性也已得到学界认可，但相关研究总体仍较为匮乏。其中一个典型案例便是近期在部分不列颠哥伦比亚省内小坎贝尔河（Little Campbell River）流域的三棘刺鱼（Gasterosteus aculeatus）种群中记录到的雌性喉部红色着色现象。尽管雌性三棘刺鱼通常会对雄性喉部的红色着色表现出偏好，但针对雌性体色所受性选择可能性的研究却极少。本研究利用采自不列颠哥伦比亚省小坎贝尔河的野生三棘刺鱼，通过顺序式与同步式择偶试验，探究了雄性对雌性喉部色泽、骨盆棘颜色以及标准体长的择偶偏好。多变量分析结果显示，未发现种群水平上雄性存在择偶偏好的证据，这表明雄性择偶并未对这些性状产生定向性选择压力。研究同时检测到雄性间的偏好函数存在显著差异，但该差异源于不同雄性在交配试验中的平均响应水平差异，而非偏好强度（即斜率）的变化，这表明雄性个体层面亦不存在针对性的择偶偏好。当遭遇同种雄性入侵者时，雄性的响应程度会随入侵者喉部红色着色程度的加深而减弱，这表明在本实验中雄性能够分辨体色与其他表型特征，且雄性可能在种内互动中利用这些性状。本研究结果首次明确探究了三棘刺鱼雄性对雌性喉部色泽的择偶偏好。