在寻找伴侣的时候，雌古比鱼（孔雀鱼）会寻找特殊的另一半。根据最近在线发表于《自然》杂志上的新研究，雌古比鱼在择偶上的价值选择——特别是对那些闪亮的、有彩色标志的雄鱼的偏好——可能会促使野生鱼群产生令人惊讶的多样性。
在实验室中，雌古比鱼显示出对有着罕见标志的雄鱼的偏好。现在，研究人员已经通过改变特立尼达岛的鱼塘中不同鳍形的比率证实了该结果。他们根据野生雄鱼的尾鳍的大部分是透明还是彩色的，将其分成了两组，然后重新将其放入不同的饲养池。他们等待了16到17天，雌鱼与其最喜欢的雄性进行了配对，然后研究人员对这些雌鱼的幼鱼进行了亲子鉴定。
根据第一轮后代（共693条古比鱼）测试的结果，他们发现，一种罕见的雄鱼比普通雄鱼的后代多两倍，而无论它身上的图案是怎样的。这一结果背后的进化原因尚不清楚，不过这可能是一种避免基因相似的鱼发生近亲交配的方法，由此可能创造出更加多样化的种群。(生物谷Bioon.com)
生物谷推荐的英文摘要
Nature doi:10.1038/nature12717
Mating advantage for rare males in wild guppy populations
Kimberly A. Hughes,Anne E. Houde,Anna C. Price & F. Helen Rodd
To understand the processes that maintain genetic diversity is a long-standing challenge in evolutionary biology, with implications for predicting disease resistance, response to environmental change, and population persistence1, 2, 3. Simple population genetic models are not sufficient to explain the high levels of genetic diversity sometimes observed in ecologically important traits2. In guppies (Poecilia reticulata), male colour pattern is both diverse and heritable, and is arguably one of the most extreme examples of morphological polymorphism known4, 5. Negative frequency-dependent selection (NFDS), a form of selection in which genotypes are favoured when they are rare6, can potentially maintain such extensive polymorphism, but few experimental studies have confirmed its operation in nature7, 8. Here we use highly replicated experimental manipulations of natural populations to show that males with rare colour patterns have higher reproductive fitness, demonstrating NFDS mediated by sexual selection. Rare males acquired more mates and sired more offspring compared to common males and, as previously reported, had higher rates of survival8. Orange colour, implicated in other studies of sexual selection in guppies, did predict male reproductive success, but only in one of three populations. These data support the hypothesis that NFDS maintains diversity in the colour patterns of male guppies through two selective agents, mates and predators. Similar field-based manipulations of genotype frequencies could provide a powerful approach to reveal the underlying ecological and behavioural mechanisms that maintain genetic and phenotypic diversity.
