Data from: Social interactions predict genetic diversification: an experimental manipulation in shorebirds

Mating strategy and social behaviour influence gene flow and thus affect levels of genetic differentiation and potentially speciation. Previous genetic analyses of closely related plovers Charadrius spp. found strikingly different population genetic structure in Madagascar: Kittlitz’s plovers are spatially homogenous whereas white-fronted plovers have well segregated and geographically distinct populations. Here we test the hypotheses that Kittlitz’s plovers are spatially interconnected and have extensive social interactions that facilitate gene flow, whereas white-fronted plovers are spatially discrete and have limited social interactions. By experimentally removing mates from breeding pairs and observing the movements of mate-searching plovers in both species, we compare the spatial behaviour of Kittlitz’s and white-fronted plovers within a breeding season. The behaviour of experimental birds was largely consistent with expectations: Kittlitz’s plovers travelled further, sought new mates in larger areas, and interacted with more individuals than white-fronted plovers, however there was no difference in breeding dispersal. These results suggest that mating strategies, through spatial behaviour and social interactions, are predictors of gene flow and thus genetic differentiation and speciation. Our study highlights the importance of using social behaviour to understand gene flow, although future work is needed to investigate the relative importance of social structure, intra- and between-season dispersal in influencing the genetic structures of populations.

婚配策略与社会行为可影响基因流，进而作用于遗传分化水平乃至物种形成过程。此前针对近缘鸻属（Charadrius）鸟类的遗传学研究在马达加斯加地区得到了显著迥异的种群遗传结构特征：基利茨鸻（Kittlitz’s plovers）的种群空间分布均一，而白额鸻（white-fronted plovers）则形成了高度分化且地理特征鲜明的种群结构。本研究旨在验证两项假说：基利茨鸻具备广泛的空间连通性与社会互动，可促进基因流；反之白额鸻空间分布离散且社会互动有限。我们通过实验移除繁殖配对中的配偶，并观测两种鸻寻找新配偶时的移动行为，进而在单个繁殖季内对比基利茨鸻与白额鸻的空间行为差异。实验组个体的行为整体符合预期：相较于白额鸻，基利茨鸻的移动距离更远，择偶活动范围更广，且互动的个体数量更多，但二者在繁殖扩散层面并无显著差异。上述结果表明，婚配策略可通过空间行为与社会互动成为基因流、乃至遗传分化与物种形成的预测因子。本研究强调了借助社会行为解析基因流机制的重要性，未来仍需进一步探究社会结构、季内与季间扩散对种群遗传结构的相对影响权重。