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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=612920
• 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.

为什么有些动物是社会性的，而另一些则不是，这是动物行为研究的一个主要领域。虽然群体中的个体可以从集体检测捕食者或帮助彼此抚养后代中受益，但它们也会招致更多的成本，例如对食物或配偶的更多竞争以及生殖机会的丧失。我的研究计划侧重于通过考察这些成本和收益来理解社会性的演变。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接近的竞争对手。在这类群体中的繁殖并不是平均分配的，成功往往取决于支配地位或攻击性。在平等主义社会中，人们对影响生殖分配的因素知之甚少，因为这些社会没有使用咄咄逼人的手段竞争资源，即使我们观察到生育成功不平等。我们将测试与影响雌性繁殖成功的因素有关的假设，在一个物种中，似乎是一个平等的社会制度(所有成年人都生育，没有统治等级)，但在这个物种中，一些雌性繁殖的后代比其他雌性多得多。虽然雌性可能会争夺资源，但雄性预计会通过性选择来竞争配偶。最先由达尔文描述的性选择包括一种性别直接竞争获得另一种性别的机会或由一种性别选择配偶。这种竞争或选择可能会导致适应，包括大鹿角和色彩鲜艳的羽毛。然而，如果一只雌性与不止一只雄性交配，那么雌性的生殖道也会发生竞争。因此，我们试图了解的不仅仅是性选择的可见结果(例如孔雀的尾巴)，因为单靠交配并不能确保受精。我们将研究不同社会情况下精子和其他生殖结构在形态和功能上的具体差异。了解男性精子形态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。我们将使用行为学、分子和内分泌技术的组合，在独居和群居的自由放养地鼠，特别是群居的非洲地松鼠(Xerus Inauris)身上测试关于社会行为、生殖和性选择进化的关键假设。随着我们开发了20个分子标记，使我们能够确定这些非洲松鼠的详细遗传关系，我们即将将这项研究过渡到一个新的理解水平。我们的研究结果将对进化生物学和生育研究具有理论和应用意义。