Department of Ecology and Evolutionary Biology, Rice University, Houston, TX 77005, USA.
Ecol Lett. 2013 Mar;16(3):354-61. doi: 10.1111/ele.12049. Epub 2012 Dec 12.
Understanding and predicting range expansion are key objectives in many basic and applied contexts. Among dioecious organisms, there is strong evidence for sex differences in dispersal, which could alter the sex ratio at the expansion's leading edge. However, demographic stochasticity could also affect leading-edge sex ratios, perhaps overwhelming sex-biased dispersal. We used insects in laboratory mesocosms to test the effects of sex-biased dispersal on range expansion, and a simulation model to explore interactive effects of sex-biased dispersal and demographic stochasticity. Sex-biased dispersal created spatial clines in the sex ratio, which influenced offspring production at the front and altered invasion velocity. Increasing female dispersal relative to males accelerated spread, despite the prediction that demographic stochasticity would weaken a signal of sex-biased dispersal. Our results provide the first experimental evidence for an influence of sex-biased dispersal on invasion velocity, highlighting the value of accounting for sex structure in studies of range expansion.
理解和预测分布范围的扩展是许多基础和应用研究的主要目标。在雌雄异体的生物中，有大量证据表明在扩散过程中存在性别差异，这可能会改变扩展前沿的性别比例。然而，人口统计学上的随机性也可能会影响前沿的性别比例，也许会压倒性别偏向的扩散。我们使用昆虫在实验室中进行中观生态系统的实验，以测试性别偏向扩散对分布范围扩展的影响，并使用模拟模型来探索性别偏向扩散和人口统计学随机性的相互作用。性别偏向扩散在性别比例上产生了空间梯度，这影响了前沿的后代产生，并改变了入侵速度。与雄性相比，雌性的扩散比例增加会加速扩散，尽管预测人口统计学随机性会削弱性别偏向扩散的信号。我们的研究结果为性别偏向扩散对入侵速度的影响提供了第一个实验证据，突出了在研究分布范围扩展时考虑性别结构的重要性。
