Data from: Investigating hybridization between the two sibling bat species Myotis myotis and M. blythii from guano in a natural mixed maternity colony

Because they can form seasonal mixed-species groups during mating and maternal care, bats are exciting models for studying interspecific hybridization. Myotis myotis and M. blythii are genetically close and morphologically almost identical, but they differ in some aspects of their ecology and life-history traits. When they occur in sympatry, they often form large mixed maternity colonies, in which their relative abundance can vary across time due to a shift in the timing of parturition. For the first time, we used non-invasive genetic methods to assess the hybridization rate and colony composition in a maternity colony of M. myotis and M. blythii located in the French Alps. Bat guano was collected on five sampling dates spread across the roost occupancy period and was analysed for individual genotype. We investigated whether the presence of hybrids followed the pattern of one of the parental species or if it was intermediate. We identified 140 M. myotis, 12 M. blythii and 13 hybrids among 250 samples. Parental species appeared as genetically well-differentiated clusters, with an asymmetrical introgression towards M. blythii. By studying colony parameters (effective size, sex ratio and proportion of the three bat types) across the sampling dates, we found that the abundances of hybrid and M. blythii individuals were positively correlated. Our study provides a promising non-invasive method to study hybridization in bats and raises questions about the taxonomic status of the two Myotis species. We discuss the contribution of this study to the knowledge of hybrid ecology, and we make recommendations for possible future research to better understand the ecology and behaviour of hybrid individuals.由于蝙蝠在交配与育幼阶段可形成季节性跨物种混合群，其成为研究种间杂交的极具潜力的模型体系。鼠耳蝠属（Myotis）的Myotis myotis与M. blythii遗传关系紧密，形态特征几乎完全一致，但在部分生态与生活史性状上存在差异。当二者同域分布时，常会形成大型混合产仔群，且由于两者产仔时间存在差异，群内二者的相对丰度会随时间发生变化。本研究首次采用非侵入式遗传方法，针对法国阿尔卑斯山区一处栖息有Myotis myotis与M. blythii的产仔群，评估其杂交发生率与种群组成情况。研究人员在该栖息点的占用周期内分5次采样收集蝙蝠粪便，并对个体基因型进行分析。本研究旨在探究杂交个体的出现模式是更趋近于某一亲本物种，还是呈现中间过渡类型。在250份样本中，共鉴定出140只Myotis myotis、12只M. blythii以及13只杂交个体。亲本物种在遗传上呈现出清晰的分化类群，且存在偏向M. blythii的不对称基因渐渗现象。通过分析采样周期内的种群参数（有效种群大小、性比以及三类蝙蝠的占比），研究发现杂交个体与M. blythii的丰度呈显著正相关。本研究提出了一种极具应用前景的非侵入式方法用于蝙蝠杂交研究，并对这两种鼠耳蝠的分类学地位提出了疑问。本研究讨论了其在杂交生态学研究领域的学术贡献，并为未来进一步探究杂交个体的生态与行为特征提出了研究建议。