Maintenance of Variation in Sexually Selected Traits: a Nutritional Ecology Approach

遗传变异如何维持在增强适应性的性状中，仍然是进化生物学中的一个基本难题。目前已经提出了几种主要的理论来解释遗传变异的持久性，包括基因捕获、频率依赖适应度、波动选择、基因型-环境相互作用、基因型-基因型相互作用、杂种优势和拮抗多效性。我和我的学生正在用动物行为方法测试其中的一些理论，该方法结合了营养生态学、生态生理学和数量遗传学的工具。我们以实验室为基础的实证研究量化了条件、生活史特征和性选择特征的表型和遗传变异，并确定了这种变异如何受到饮食和生理的影响。我们的前三个研究目标为检验维持适应性特征变异的假设奠定了基础。我们将估计性特征的结构和女性偏好函数，以了解特征如何可能经历选择；量化饮食如何影响性特征，以确定其条件依赖性；并评估饮食如何影响性特征变化的生理基础。然后，我们将测试基因捕获假说，并量化雌性是否从与首选伴侣交配中获得间接利益。最后，我们将检验频率相关适应度是否能维持这些性特征的差异。总之，这项工作将确定性特征的多元结构，它们的条件依赖性，它们的生理和遗传基础，雌性是否获得间接利益，以及频率依赖性适应性的潜力。总的来说，我们的研究将明确地检验上述两种理论，以维持高遗传变异-基因捕获和频率依赖适应度。从长远来看，我的研究计划的首要目标是有助于更全面地了解如何在提高适应性的性状中保持高遗传变异。

How genetic variation is maintained in traits that enhance fitness remains a fundamental dilemma in evolutionary biology. Several major theories have been put forth to explain the persistence of genetic variance including genic capture, frequency dependent fitness, fluctuating selection, genotype-by-environment interactions, genotype-by-genotype interactions, heterosis, and antagonistic pleiotropy. My students and I are testing some of these theories using an animal behaviour approach that incorporates tools from nutritional ecology, ecological physiology, and quantitative genetics. Our laboratory-based empirical research quantifies the phenotypic and genetically based variation in condition, life-history traits, and sexually selected traits and determines how this variation is influenced by diet and physiology. Our first three research goals lay the foundation needed to test hypotheses for maintaining variation in fitness traits. We will estimate the structure of sexual traits and female preference functions to understand how traits are likely to experience selection; quantify how diet affects sexual traits to determine their condition-dependent nature; and assess how diet influences the physiological foundations of sexual trait variation. We will then test the genic capture hypothesis and quantify whether females receive indirect benefits from mating with preferred mates. Lastly, we will test whether frequency-dependent fitness can maintain variance in these sexual traits. Together this work will determine the multivariate structure of the sexual traits, their condition-dependent nature, their physiological and genetic underpinnings, whether females receive indirect benefits, and the potential for frequency-dependent fitness. Overall, our research will explicitly test two of the above theories for the maintenance of high genetic variance - genic capture and frequency-dependent fitness. Long-term, the overarching goal of my research program is to contribute to a more complete understanding of how high genetic variance is maintained in traits that enhance fitness.