Evolutionary ecology of parental care: sexual selection, fitness and alternative personalities

传统的性选择理论通常基于这样的假设，即在潜在配偶中进行选择会带来巨大的遗传(或间接)好处。然而，越来越多的经验证据表明，这一假设可能并不总是有效的，而且在某些系统中，择偶的非遗传(或直接)好处可能比之前意识到的更重要。这项研究的总体目标是对野生种群中性别选择的直接模型进行最全面的实证检验，使用鸟类的父母照料作为我们的模型系统。鸟类的父母照料是这类测试的一个很好的框架，因为鸟类提供了许多性选择的经典例子，父母照料提供了一种直接受益可能很大的情景。对于这个项目，我们将使用已经建立的岛上家麻雀种群Passer Home ticus，它非常适合我们的需求，因为我们可以监测所有个体的终生繁殖和存活，从而使我们能够以异常精确的方式估计健康成分。对于这个群体，我们也有一个长期交叉培育的育种谱系，这将使我们能够估计广泛的遗传和非遗传因素的相对作用。此外，我们还将测试男性所提供的父母照顾的数量与其生殖行为的其他方面之间的联系。例如，我们特别感兴趣的是，男性在父母照顾上的努力与他寻找更多性伴侣的能力之间是否存在权衡。最后，基于我们收集的经验数据，我们将建立一个理论模型，试图解释为什么不同的人在提供父母照顾时会表现出如此不同的策略，并探索这种差异是否反映了个体之间的总体‘个性’的差异。

Traditional theories of sexual selection are often based on the assumption that there are substantial genetic (or 'indirect') benefits to be accrued from choosing among potential mates. There is growing empirical evidence, however, that this assumption may not always be valid and that in some systems non-genetic (or 'direct') benefits of mate choice may be more important than previously realised. The overall aim of this study is to conduct the most comprehensive empirical test of direct models of sexual selection in a wild population, using parental care in birds as our model system. Parental care in birds is a good framework for this type of test because birds provide many of the classic examples in sexual selection and parental care provides a scenario where direct benefits may be substantial. For this project we will use an already established, island population of house sparrows, Passer domesticus, which is ideally suited to our needs because we can monitor both lifetime reproduction and survival for all individuals, thereby allowing us to estimate fitness components with unusual precision. For this population we also have a long-term cross-fostered breeding pedigree, which will allow us to estimate the relative roles of a wide range of genetic and non-genetic factors. In addition, we will also test for links between the amount of parental care that a male provides and other aspects of his reproductive behaviour. We are particularly interested, for instance, in whether there is a trade-off between the amount of effort a male expends on parental care and his ability to seek additional sexual partners. Finally, based on the empirical data that we gather, we will build a theoretical model that seeks to explain why different individuals display such different strategies when it comes to the provision of parental care, and explores whether this variation reflects differences in overall 'personality' among individuals.