The interplay between natural and sexual selection: causes and consequences

我和我的学生研究动物繁殖策略的演变和灵活性。在这里，我们关注特里尼迪亚孔雀鱼，这是一种小型淡水鱼，在雄鱼的性特征和雌鱼的配偶选择偏好上表现出相当大的差异。我们之前的研究表明，雌性对雄性橙色斑点的主要配偶偏好源于对橙色水果的觅食偏好。我们正在测试对橙色偏向的种群间差异的几种解释。例如，这是否源于颜色视觉的差异，这可能是由于它们栖息地的不同而进化出来的，包括一种用爪子上的橙色斑点来引诱孔雀鱼的捕食者？雌性金枪鱼还使用第二个标准来选择配偶--它们更喜欢稀有或新奇颜色图案的雄性。这可能有助于它们避免与亲戚交配，从而降低其后代患严重遗传疾病的风险；这种“罕见的雄性”效应也有助于维持高水平的遗传多样性。在这里，我们将确定具有共同的、因此令人反感的颜色模式的雄性是否会从事试图寻找配偶的危险行为。另一个目标是确定这种配偶偏好的神经学基础。它是否进化为对新奇事物的一系列反应的一部分，包括探索新的、潜在的生产性栖息地或食物来源的动机？我们将重点放在多巴胺的作用上，因为它会影响包括人类在内的多种动物对新奇事物的反应。一些最有成效的研究领域处于自然行为变异研究和神经生物学的交界处。很少有研究记录多个种群的配偶选择偏好的差异，随着我们对孔雀鱼生态和进化的丰富了解，这是一个难得的机会来充分了解导致这种差异的因素。管理和保护加拿大野生动物的生物学家将从我们的发现中受益；例如，我们的见解(I)可能会加强动物不愿交配的圈养繁殖计划，(Ii)应该提高我们对当地适应的理解，以便能够评估种群内杂交和种群间杂交的成本和收益。

My students and I study the evolution of and flexibility in animal reproductive strategies. Here, we focus on Trinidadian guppies, a small freshwater fish, that shows considerable variation in male sexual traits and in female mate choice preferences. Our previous work suggests that females' main mate preference, for orange spots on males, originated with a foraging bias for orange-coloured fruit. We are testing several explanations for the inter-population variation in this bias for orange. For example, does it result from differences in colour vision, which might have evolved in response to differences in their habitats, including a predator that uses orange spots on its claws to lure guppies? Female guppies also use a second criterion for selecting mates-they prefer males with rare or novel colour patterns. This may help them to avoid mating with relatives and thus reduce the risk of serious genetic disorders in their offspring; this 'rare male' effect can also contribute to the maintenance of high levels of genetic diversity. Here, we will determine if males with common, and thus distasteful, colour patterns engage in risky behaviours attempting to find mates. Another goal is to determine the neurological basis for this mate preference. Has it evolved as part of a suite of responses to novelty, including a motivation to explore new, potentially productive habitats or sources of food? We are focusing on the role of dopamine because it influences responsiveness to novelty in a wide range of animals, including humans. Some of the most productive areas of research are at the interface between studies of natural behaviour variants and neurobiology. Few studies have documented variation in mate choice preferences across multiple populations and, with our rich understanding of guppy ecology and evolution, this is a rare opportunity to fully understand the factors responsible for this variation. Biologists managing and conserving Canadian wildlife will benefit from our findings; for example, our insights (i) may enhance captive breeding programs where animals have been reluctant to mate and (ii) should improve our understanding of local adaptation so that the costs and benefits of within- versus between population crosses can be evaluated.