Female mate choice based on multiple male traits and adaptive offspring manipulation

这项研究的目的是研究在日本冲绳野生孔雀鱼的每一个雄性特征的基础上选择雌性配偶的收益和成本，以及雌性对其配偶的适应性后代操纵。取得了以下研究成果：1.通过使用数字修改的男性刺激图像的视频回放，证实了女性对男性橙色斑点的色彩饱和度的显著偏好。此外，观察表明，橙色斑点颜色饱和度高的雄性海藻捕食能力更强。亲子回归分析表明，雄性孔雀鱼的觅藻能力是一个可遗传成分。觅食能力越强的雄性，生长速度越快，橙色斑点越大。这些结果表明，雌性可以获得间接的好处，如产生具有较高捕藻能力的后代，从而在雄性橙斑颜色的基础上进行配偶选择，从而获得更大的繁殖成功。据报道，雌性孔雀鱼表现出对全长较大的雄性孔雀的择偶偏好，但一些雄性孔雀尾巴(尾鳍)会拉长尾巴以达到较大的全长。在水族馆的实验中，一只雌性与两只全长相同但尾巴长度不同的雄性进行了身体接触，结果表明，雌性更喜欢短尾雄性而不是长尾雄性。雌性与长尾雄性交配会产生代价，如体型较小，女儿的生殖效率较低。然而，当雌性与长尾雄性交配时，它们会减少后代数量，并将后代性别比偏向雄性，以降低与长尾雄性交配的成本。另一方面，雄性的长尾会影响它们的游泳表现，因此将它们的栖息地限制在那些野外水流速度较慢的栖息地。

This study aimed to examine the benefits and costs of female mate choice on the basis of each male trait and adaptive offspring manipulation by females depending on their mates using feral guppies Poecilia reticulata in Okinawa, Japan. The following results were obtained.1. By using digitally modified video playbacks of stimulus male images, a significant female preference for the color saturation of male orange spots was confirmed. In addition, observations indicated that males possessing the high color saturation of orange spots exhibited a greater algal-foraging ability. Parent-offspring regression analysis demonstrated that the algal-foraging ability of male guppies was a heritable component. Males possessing higher algal-foraging ability exhibited faster growth and larger orange spots. These results suggest that females can acquire indirect benefits such as producing offspring possessing the high algal-foraging ability and thus a greater reproductive success via their mate choice on the basis of male orange spot coloration.2. It has been reported that female guppies exhibited mate preference for males possessing large total lengths, however some males elongated their tails (caudal fins) to achieve large total lengths. Aquarium experiments in which a female physically contacted with two males exhibiting same total lengths but possessing different tail lengths indicated that the females preferred the short-tailed males over the long-tailed males. Females incurred costs of mating with long-tailed males, such as small body sizes and low reproductive efficiency of their daughters. However, when females mated with long-tailed males, they decreased the number of offspring and biased offspring sex ratio toward males in order to reduce the costs of mating with the long-tailed males. On the other hand, long tails of males affected their swimming performance and consequently limited their choice of habitats to those with slow water velocity in the wild.