Department of Biological Sciences, University of Windsor, Windsor, ON, Canada.
J Evol Biol. 2010 Jun 1;23(6):1331-8. doi: 10.1111/j.1420-9101.2010.01996.x. Epub 2010 Apr 23.
Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high-predation populations compared to low-predation populations. Here, we assess the possible evolutionary consequences of these patterns by asking whether variation in sperm traits reflect differences in predation intensity among four pairs of Trinidadian populations: four that experience relatively low levels of predation from a gape-limited predator and four that experience relatively high levels of predation from a variety of piscivores. We found that males in high-predation populations had faster swimming sperm with longer midpieces compared to males in low-predation populations. However, we found no differences among males in high- and low-predation populations with respect to sperm number, sperm head length, flagellum length and total sperm length.
孔雀鱼（Poecilia reticulata）是研究自然选择和性选择相互作用的模式生物。捕食压力被认为是影响雌性性选择偏好、雄性交配策略和精子竞争水平的主要因素。在捕食压力较高的情况下，雌性通常会降低对华丽雄性的偏好，并更多地采取防御行为，而雄性则会利用这些变化，从性炫耀行为转变为强制交配。这些模式可以解释为什么在高捕食压力的种群中，与低捕食压力的种群相比，多父本现象更为普遍。在这里，我们通过比较来自四个具有不同捕食压力的特立尼达种群的雄性，来评估这些模式的可能进化后果：四个种群受到一种口裂有限的捕食者的低捕食压力，而另外四个种群受到多种鱼类捕食者的高捕食压力。我们发现，与低捕食压力种群的雄性相比，高捕食压力种群的雄性具有更快的游动速度和更长的中段。然而，我们没有发现高捕食压力和低捕食压力种群的雄性在精子数量、精子头部长度、鞭毛长度和总精子长度方面存在差异。
