DISSERTATION RESEARCH: Spatial variation in bill morphology and genetic structure in the Island Scrub-Jay: Adaptive divergence within a single-island endemic?

自达尔文以来，适应性分化的空间尺度和驱动它的机制一直处于进化辩论的前沿。由于鸟类可以飞行，种群之间的扩散和基因流动传统上被认为是高水平的，导致对当地适应和分化的限制。然而，越来越多的证据表明，即使在存在基因流的情况下，分歧选择也可以促进相邻鸟类种群之间的适应性差异。最近，在加利福尼亚州南部的一个岛屿上发现了小规模的嘴形态适应性分化模式。这项工作将扩展到测试假想的促进基因流分化的机制，包括跨生境交错带的破坏性选择以及与配偶选择相关的性状的连锁。除了对理解适应性分化的规模的影响之外，收集的数据将被用于为旨在保护海岛灌木鸟的管理战略提供信息。一种总种群规模估计为3000只的物种。对这种独特的岛屿地方性疾病的研究还将通过为高中生创建教育活动以及通过在开展工作的岛屿上进一步发展和促进公民科学计划来吸引公众参与。

The spatial scale of adaptive differentiation and the mechanisms that drive it has been at the forefront of evolutionary debate since Darwin. Because birds can fly, dispersal and gene flow between populations has traditionally been thought to be high, leading to constraints on local adaptation and divergence. Yet, increasingly evidence is accumulating that divergent selection can promote adaptive differences between adjacent bird populations even in the presence of gene flow. Recently, small-scale patterns of adaptive differentiation in bill morphology were detected in the Island Scrub-Jay (Aphelocoma insularis), a species that is confined to a single island in southern California. This work will be extended to test mechanisms hypothesized to facilitate divergence with gene flow, including disruptive selection across habitat ecotones and linkage with traits related to mate choice. Beyond the implications for understanding the scale of adaptive differentiation, the data collected will be used to inform management strategies aimed at conserving the Island Scrub-Jay ? a species that has a total population size estimated at 3000 individuals. Research on this unique insular endemic will also be used to engage the public by creating educational activities for high school students and by further developing and promoting a citizen science program on the island where the work is conducted.