Data from: 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 females also had the greatest levels of skew in fertilization success of males. Thus, our results show that X. birchmanni has a polygynandrous mating system and that introgression of X. malinche alleles has only subtle effects on mating patterns in this species.

正如交配模式可推动物种形成或杂交事件的发生，种群内的杂交现象亦可反过来塑造其交配模式。本研究以自然杂交的剑尾鱼物种——伯氏剑尾鱼（Xiphophorus birchmanni）为研究对象，解析了其多重交配模式与生殖偏倚（reproductive skew）特征。我们采用微卫星标记（microsatellite marker）对采自2个野生种群的43条雌鱼所产胚胎进行基因型分型，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, SNP）标记，将雌鱼及其推断的配偶分别归类为亲本型伯氏剑尾鱼，或是携带姊妹种马林切剑尾鱼（X. malinche）等位基因的渗入型个体。研究发现，亲本型与渗入型伯氏剑尾鱼雌鱼，均会与亲本型及渗入型雄鱼进行多重交配。我们未观察到亲本型与渗入型伯氏剑尾鱼雌鱼在交配模式或生殖偏倚水平上存在显著差异。然而，非渗入型伯氏剑尾鱼雄鱼更倾向于与体型较大、繁殖力旺盛的雌鱼交配，这类雌鱼同时也表现出最高的雄性受精成功生殖偏倚水平。综上，本研究结果表明，伯氏剑尾鱼具有多雌多雄的交配系统，而马林切剑尾鱼等位基因的渗入仅对该物种的交配模式产生微弱影响。