Biology Department, Queen's University, Kingston, ON, Canada.
Evolution. 2023 Jul 27;77(8):1756-1768. doi: 10.1093/evolut/qpad098.
We ask if three decades and over 1,500 generations of divergent life-history selection on age at reproduction has resulted in the evolution of reproductive isolation (RI) between laboratory populations of Drosophila melanogaster. We tested for premating, postmating-prezygotic, and postzygotic reproductive isolation between three replicate population pairs. Large, evolved differences in body size between selection treatments suggested the potential for prezygotic barriers driven by sexual selection or physical incompatibilities between the sexes. Although a simple prediction would be preference for larger size, creating directional isolation, our results from individual mate choice trials indicate that populations from both selection treatments show a marked bias towards homotypic mate choice; indicative of prezygotic RI driven by sexual selection or sexual conflict. Hybridization between the focal populations resulted in the production of viable adult flies with intermediate size and developmental traits. We observed a suggestive but statistically nonsignificant trend of fitness decline in the F2 generation of hybrids, but no significant evidence suggesting the evolution of postmating-prezygotic or postzygotic RI. Our findings are in accord with extant literature that posits that premating RI evolves before postmating forms of RI.
我们探讨了在 30 多年的时间里，对生殖年龄进行超过 1500 代的分歧选择，是否导致了黑腹果蝇实验室种群之间生殖隔离（RI）的进化。我们测试了三个重复种群对之间的交配前、交配后-合子前和合子后生殖隔离。选择处理之间的体型大小的巨大、进化差异表明，性选择或两性之间的物理不相容性可能导致了合子前障碍。尽管一个简单的预测是对更大体型的偏好，从而产生定向隔离，但我们来自个体交配选择试验的结果表明，来自两种选择处理的种群都表现出对同型交配的明显偏好；这表明由性选择或性冲突驱动的合子前 RI。焦点种群之间的杂交产生了具有中间体型和发育特征的可育成年果蝇。我们观察到杂种 F2 代的适应性呈下降趋势，但没有明显的证据表明交配后-合子前或合子后 RI 的进化。我们的研究结果与现有的文献一致，即认为交配前 RI 先于交配后 RI 形式进化。
