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进化和灵活性。在这里，我们关注的是特立尼达孔雀鱼，一种小型淡水鱼，在雄性性特征和雌性择偶偏好方面表现出相当大的差异。我们之前的研究表明，雌性对雄性身上橙色斑点的主要择偶偏好，源于对橙色水果的觅食偏好。我们正在测试几种解释，以解释这种橙色偏倚的种群间差异。例如，这是由于颜色视觉的差异造成的吗？这可能是由于它们栖息地的差异而进化而来的，包括一种捕食者用爪子上的橙色斑点来引诱孔雀鱼？雌性孔雀鱼还使用第二条标准来选择配偶——它们更喜欢具有罕见或新颖颜色图案的雄性。这可能有助于它们避免与亲属交配，从而降低后代患严重遗传疾病的风险；这种“罕见男性”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图案的雄性是否会采取冒险的行为来寻找配偶。另一个目标是确定这种择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？我们之所以关注多巴胺的作用，是因为它影响着包括人类在内的许多动物对新鲜事物的反应。一些最有成效的研究领域是自然行为变异研究和神经生物学研究的交叉点。很少有研究记录了多个种群中配偶选择偏好的变化，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，可以充分了解导致这种变化的因素。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)可以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，以便可以评估种群内与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.