Dissertation Research: Evolutionary and Ecological Determinants of Incubation Strategies in Three Sympatric Nuthatches

亲代照顾策略的进化被认为是由提供照顾的健康成本和收益决定的。鸟类孵化是亲代照顾的一种形式，能量限制被认为是孵化策略的种内和种间变化的基础。然而，这些结论几乎完全是基于单一物种的研究，这可能反映了表型而不是遗传差异。巢捕食是另一种解释，被认为是一种潜在的选择压力，导致不同的孵化策略，但缺乏关键的测试。研究人员提出在三种同域种中对能量约束和巢捕食风险假设进行实验验证。这些物种提供了一个模型系统来测试这些假设，因为它们在能量约束和巢穴捕食风险方面存在相反的方向。能量约束假说将通过向巢内注入冷热空气来改变巢内小气候的实验来验证。巢穴捕食风险假说将通过捕食者呈现实验进行验证。这项实验和比较领域的工作促进了对亲代照顾的种内和种间变异的因素的理解。l J

Martin 9701116 Evolution of parental care strategies is thought to be determined by fitness costs and benefits associated with providing care. Avian incubation is a form of parental care and energetic constraints are thought to underlie intra- and interspecific variation in incubation strategies. However, these conclusions are based almost exclusively on single species studies which may reflect phenotypic rather than genetic differences. Nest predation is an alternative explanation that has been proposed as a potential selection pressure leading to different incubation strategies, but critical tests are lacking. The PIs propose to experimentally test the energetic constraint and nest predation risk hypotheses in three sympatric species in the genus Sitta. These species provide a model system to test these hypotheses because they differ in opposite directions with respect to energetic constraints and nest predation risk. The energetic constraint hypothesis will be tested by experimentally modifying the nest microclimate using warm and cold air pumped into nests. The nest predation risk hypothesis will be tested through predator presentation experiments. This experimental and comparative field work advances understanding of the factors responsible for intra and interspecific variation in parental care. l J