The magnitude of behavioral isolation is affected by characteristics of the mating community

Gene exchange between species occurs in areas of secondary contact, where two species have the opportunity to hybridize. If heterospecific males are more common than conspecific males, females will experience more encounters with males of other species. These encounters might increase the likelihood of heterospecific matings, and lead to the production of hybrid progeny. I studied the mating behavior of two pairs of sibling species endemic to Africa: Drosophila yakuba/D. santomea and D. simulans/D. sechellia. Drosophila yakuba and D. simulans are cosmopolitan species widely distributed in the African continent, while D. santomea and D. sechellia are island endemics. These pairs of species hybridize in nature and have the potential to exchange genes in natural conditions. I used these two pairs of Drosophila species, and constructed mating communities of different size and different heterospecific:conspecific composition. I found that both the total number of potential mates and the rela...物种间的基因交流发生于二次接触区域——在此类区域中，两个物种拥有发生杂交的机会。若异种雄性的种群丰度高于同种雄性，雌性个体遭遇异种雄性的频次将显著提升。此类邂逅事件可能提高异种交配的概率，进而产生杂交子代。本研究针对两对非洲特有姊妹种的交配行为展开探究：分别为雅库巴果蝇（Drosophila yakuba）/圣多美果蝇（D. santomea）以及拟果蝇（Drosophila simulans）/塞舌尔果蝇（D. sechellia）。雅库巴果蝇与拟果蝇为广布物种，广泛分布于非洲大陆；而圣多美果蝇与塞舌尔果蝇则为岛屿特有物种。上述两对物种均可在自然环境中发生杂交，且具备在自然条件下实现基因交流的潜力。本研究以这两对果蝇物种为实验材料，构建了不同规模、不同异种-同种组成比例的交配群落。本研究发现，潜在交配个体总数以及异种与同种个体的相对...