Sociality and reproductive tactics in ground-dwelling squirrels: conflict and cooperation

地栖松鼠的社会性和繁殖策略：冲突与合作

• 批准号: RGPIN-2015-04362
• 负责人: Waterman, Jane
• 金额: $ 2.33万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=668238
• 关键词: Sociality; reproductive; tactics; ground; dwelling

Why some animals are social and others are not is a major area of research in animal behaviour. Although individuals in groups can benefit from collective detection of predators or helping each other raise offspring, they also incur increased costs, such as more competition for food or mates and the loss of reproductive opportunities. My research program focuses on understanding the evolution of sociality by examining these costs and benefits. In complex animal societies, females usually live with their close kin but these close kin are also their closest competitors. Reproduction in such groups is not equally distributed and success is often determined by dominance or aggression. Less is known about the factors influencing reproductive distribution in egalitarian societies that do not use aggressive means of competing for resources, even when we observe unequal reproductive success. We will test hypotheses related to the factors that influence female reproductive success in a species with what appears to be an egalitarian social system (all adults breed and there is no dominance hierarchy), but where some females wean far more offspring than others. While females may compete for resources, males are predicted to compete for mates via sexual selection. First described by Darwin, sexual selection includes one sex directly competing to gain access to another or mate choice by one sex. Such competition or choice can lead to adaptations including large antlers and brightly coloured feathers. However, if a female mates with more than a single male, then competition can also occur in the reproductive tract of the female. Thus we seek to understand more than just the visible results of sexual selection (e.g. peacock's tail), as copulations alone do not ensure fertilization. We will examine specific differences in the morphology and functioning of sperm and other reproductive structures under different social situations. Understanding differences in sperm form and function among males may be the ultimate key to understanding reproductive success, yet few studies have investigated these differences. We will test critical hypotheses about the evolution of social behaviour, reproduction, and sexual selection in solitary and social, free-ranging ground squirrels, particularly the social African ground squirrel (Xerus inauris), using a combination of behavioural, molecular and endocrine techniques. With our development of 20 molecular markers that allow us to determine detailed genetic relationships in these African squirrels, we are on the edge of transitioning this research to a new level of understanding. Results of our research will have both theoretical and applied implications to evolutionary biology and fertility research.

为什么有些动物是群居动物，而另一些动物不是，这是动物行为研究的一个主要领域。尽管群体中的个体可以从集体发现捕食者或帮助彼此抚养后代中受益，但它们也会带来更大的成本，例如对食物或配偶的更多竞争以及繁殖机会的丧失。我的研究项目侧重于通过研究这些成本和收益来了解社会性的演变。在复杂的动物社会中，雌性通常与它们的近亲生活在一起，但这些近亲也是它们最亲密的竞争对手。这些群体的繁殖分布并不均匀，成功往往取决于统治或侵略。即使我们观察到不平等的生殖成功，对于不使用侵略性手段来竞争资源的平等社会中影响生殖分配的因素知之甚少。我们将测试与影响雌性繁殖成功的因素有关的假设，该物种具有似乎是平等主义的社会制度（所有成年人都繁殖并且没有统治等级），但某些雌性断奶的后代比其他雌性要多得多。虽然雌性可能会争夺资源，但预计雄性会通过性选择来竞争配偶。达尔文首先描述，性选择包括一种性别直接竞争以获得另一种性别的机会或一种性别的择偶选择。这种竞争或选择可能会导致适应，包括大鹿角和颜色鲜艳的羽毛。然而，如果雌性与多个雄性交配，那么雌性的生殖道也会发生竞争。因此，我们寻求的不仅仅是性选择的可见结果（例如孔雀尾巴），因为仅交配并不能确保受精。我们将研究不同社会情境下精子和其他生殖结构的形态和功能的具体差异。了解男性精子形式和功能的差异可能是了解生殖成功的最终关键，但很少有研究调查这些差异。我们将结合行为、分子和内分泌技术，测试关于独居和群居、自由放养的地松鼠，特别是社会性非洲地松鼠 (Xerus inauris) 的社会行为、繁殖和性选择进化的关键假设。随着我们开发出 20 种分子标记，使我们能够确定这些非洲松鼠的详细遗传关系，我们正处于将这项研究转变到新的理解水平的边缘。我们的研究结果将对进化生物学和生育力研究产生理论和应用意义。