The accumulation of reproductive isolation in early stages of divergence supports a role for sexual selection

Models of speciation by sexual selection propose that male-female coevolution leads to the rapid evolution of behavioral reproductive isolation. Here, we compare the strength of behavioral isolation to ecological isolation, gametic incompatibility, and hybrid inviability in a group of dichromatic stream fishes. In addition, we examine whether any of these individual barriers, or a combined measure of total isolation, is predicted by body shape differences, male color differences, environmental differences, or genetic distance. Behavioral isolation reaches the highest values of any barrier and is significantly greater than ecological isolation. No individual reproductive barrier is associated with any of the predictor variables. However, marginally significant relationships between male color and body shape differences with ecological and behavioral isolation are discussed. Differences in male color and body shape predict total reproductive isolation between species; hierarchical partiti...

性选择驱动的物种形成模型提出，雌雄个体间的协同演化可促使行为生殖隔离（behavioral reproductive isolation）快速演化。本研究针对一类双色溪流鱼类（dichromatic stream fishes），比较了行为生殖隔离与生态生殖隔离（ecological isolation）、配子不亲和性（gametic incompatibility）及杂交致死性（hybrid inviability）的强度差异。此外，本研究还检验了下述因素能否预测任一单一生殖隔离屏障，或是总隔离度的综合指标：体型差异、雄性体色差异、环境差异或遗传距离（genetic distance）。研究结果显示，行为生殖隔离的强度在所有隔离屏障中位居首位，且显著高于生态生殖隔离。未发现任一单一生殖隔离屏障与各预测变量存在显著关联。不过，本文亦探讨了雄性体色、体型差异与生态、行为生殖隔离之间存在的边际显著关联（marginally significant relationships）。雄性体色与体型差异可预测物种间的总生殖隔离程度；层级划分（hierarchical partiti...）