Multiple mating and reproductive skew in parental and introgressed females of the live-bearing fish Xiphophorus birchmanni

Just as mating patterns can promote speciation or hybridization, the presence of hybridization can shape mating patterns within a population. In this study, we characterized patterns of multiple mating and reproductive skew in a naturally hybridizing swordtail fish species, Xiphophorus birchmanni. We quantified multiple mating using microsatellite markers to genotype embryos from 43 females collected from 2 wild populations. We also used a suite of single-nucleotide polymorphism markers to categorize females and their inferred mates as either parental X. birchmanni or as introgressed individuals, which carried alleles from a sister species, X. malinche. We found that parental and introgressed X. birchmanni females mated multiply with both parental and introgressed males. We found no difference in mating patterns or reproductive skew between parental and introgressed X. birchmanni females. However, nonintrogressed X. birchmanni males mated more often with large, fecund females. These fem...正如交配模式可推动物种形成或杂交事件的发生，杂交的存在亦可塑造种群内的交配模式。本研究针对自然杂交类群的剑尾鱼物种伯氏剑尾鱼（Xiphophorus birchmanni），对其多重交配与生殖偏倚模式进行了特征解析。我们通过微卫星标记（microsatellite markers）对采自2个野生种群的43尾雌性个体的胚胎实施基因分型，以此量化多重交配水平。此外，我们利用一组单核苷酸多态性（single-nucleotide polymorphism）标记，将雌性个体及其推断的配偶划分为两类：伯氏剑尾鱼亲本个体，以及携带有姊妹物种马林切剑尾鱼（X. malinche）等位基因的渐渗个体。研究结果表明，伯氏剑尾鱼的亲本型与渐渗型雌鱼，均会与亲本型及渐渗型雄鱼发生多重交配；亲本型与渐渗型雌鱼在交配模式与生殖偏倚方面未表现出显著差异。然而，非渐渗型伯氏剑尾鱼雄鱼更倾向于与体型较大、繁殖力旺盛的雌性交配。这些雌[原文至此未完整给出]