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体，其成为研究种间杂交（interspecific hybridization）的极具潜力的模型物种。大鼠耳蝠（Myotis myotis）与布氏鼠耳蝠（M. blythii）在遗传上亲缘关系紧密，形态上几乎难以区分，但二者在部分生态特征与生活史性状（life-history traits）上存在差异。当二者同域分布（sympatry）时，常会形成大型混合育幼群体，由于产仔时间存在偏移，群体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（non-invasive genetic methods），对位于法国阿尔卑斯山区的大鼠耳蝠与布氏鼠耳蝠混合育幼群体的杂交率与群体组成进行评估。研究人员在栖息期内的5个采样时间点收集蝙蝠粪便，并对其进行个体基因型分析。本研究探究了杂交个体的出现模式是更趋近于某一亲本物种，还是呈现出介于二者之间的中间状态。在250份样本中，共鉴定出140只大鼠耳蝠、12只布氏鼠耳蝠以及13只杂交个体。亲本物种在遗传上呈现为分化良好的聚类簇，且存在向布氏鼠耳蝠倾斜的不对称基因渐渗（introgression）现象。通过分析采样时间点的群体参数（有效种群大小（effective size）、性比（sex ratio）以及三类蝙蝠的占比），研究发现杂交个体与布氏鼠耳蝠的丰度呈显著正相关。本研究提供了一种极具应用前景的蝙蝠种间杂交研究非侵入式方法，同时也引发了关于这两种鼠耳蝠属（Myotis）物种分类学地位（taxonomic status）的讨论。本研究探讨了其对杂交生态学认知的贡献，并就未来可开展的相关研究提出建议，以进一步明晰杂交个体的生态与行为特征。