Data from: From resource to female defence: the impact of roosting ecology on a bat's mating strategy

With their extraordinary species richness and diversity in ecological traits and social systems, bats are a promising taxon for testing socio-ecological hypotheses in order to get new insights into the evolution of animal social systems. Regarding its roosting habits, proboscis bats form an extreme by occupying sites which are usually completely exposed to daylight (e.g. tree trunks, vines or rocks). This is accompanied by morphological and behavioural adaptations to remain cryptic in exposed day roosts. With long-term behavioural observations and genetic parentage analyses of individually marked proboscis bats, we assessed its social dispersion and male mating strategy during day and night. Our results reveal nocturnal male territoriality—a strategy which most closely resembles a resource-defence polygyny that is frequent also in other tropical bats. Its contrasting clumped social dispersion during the day is likely to be the result of strong selection for crypsis in exposed roosts and is accompanied by direct female defence in addition to male territoriality. To the best of our knowledge, such contrasting male mating strategies within a single day–night cycle have not been described in a vertebrate species so far and illustrate a possible evolutionary trajectory from resource-defence to female-defence strategy by small ecologically driven evolutionary steps.蝙蝠类群物种丰富度极高，且生态特征与社会系统多样，是检验社会生态学假说、深入解析动物社会系统演化的理想研究类群。就栖息习性而言，长鼻蝠（proboscis bats）的栖息方式极为特殊——它们常选择完全暴露于日光之下的位点，例如树干、藤蔓或岩石表面。与此类栖息方式相伴的，是为在暴露的昼间栖息位点维持隐蔽性而演化出的形态与行为适应特征。我们通过对个体标记的长鼻蝠开展长期行为观察与遗传亲权分析，评估了该物种昼夜间的社会分布格局与雄性交配策略。研究结果显示，该物种存在夜间雄性领域行为——这一策略与其他热带蝙蝠中常见的资源防御型多配偶制（resource-defence polygyny）高度相似。与之形成鲜明对比的是，该物种昼间呈现出聚集型社会分布格局，这一特征极有可能是暴露栖息位点下强烈的隐蔽性选择压力所导致的；且除雄性领域行为外，该物种还存在直接的雌性防御行为。据我们所知，目前尚无脊椎动物物种被报道存在单日昼夜周期内截然相反的雄性交配策略的情况；该研究结果同时阐明了一条由生态驱动、通过微小演化步骤从资源防御策略向雌性防御策略演化的潜在路径。