Coordination and information transfer in bat colonies with fission-fusion behaviour

为了获得最大范围的群体利益，群体生活的个体通常需要协调他们的活动。因此，理解动物群体协作的机制、原因和后果是行为生态学的核心焦点。我们的合作项目旨在回答自然条件下群体成员之间的信息传递如何导致群体协调的问题，以共同繁殖的贝希斯坦蝙蝠Myotis bechsteinii为模型。贝希斯坦的蝙蝠群落表现出分裂融合的行为，即分裂成亚群，并重新合并亚群，这些亚群几乎每天都会转换它们的公共栖息地。蚁群成员在栖息地之间协调集体行动，以确保共同栖息，这为它们提供了群体利益，如社会体温调节。尽管群体协调对于分裂融合社会的运作具有重要意义，并且在蝙蝠群体和其他动物社会中普遍存在分裂融合行为，但只有少数研究调查了野生分裂融合社会中的信息传递和群体协调。在这项实地研究中，我们调查了贝希斯坦蝙蝠群落如何协调它们的集体栖息地转换。我们使用最近建立的无线生物网络BATS（广泛适用跟踪系统）来自动收集夜间蝙蝠的遭遇和它们在栖息地外的活动数据。为了对具有高裂变-融合动力学的蝙蝠群体集体换巢的协调提供新的见解，我们的研究旨在确定和量化个体用于寻找新栖息地和相互传递公共栖息地信息的核心行为要素（例如，夜间接近栖息地，引导-跟随行为，群体行为）。在实地实验的帮助下，我们旨在评估协调过程的灵活性，特别是关于栖息地的类型（熟悉的与新的栖息地）和相关个体的特征（例如，年龄，经验，亲属关系）。我们的项目可以建立在两个贝希斯坦蝙蝠聚居地的完全建立的现场。这些蜂群已经连续监测了27个夏天。所有群体成员都被单独标记上了pit标签，蝙蝠的人口统计学和遗传关系已经得到解决。该项目的意义在于将一项新的尖端技术（BATS-系统）与一种蝙蝠物种的长期野外数据集相结合，该数据集有可能作为裂变融合动力学和群体协调行为的模型。我们的首要目标是提高对裂变融合行为的动物社会功能的理解。

To gain the maximum range of grouping benefits, group-living individuals typically need to coordinate their activities. Understanding the mechanisms, the causes, and the consequences of group coordination in animals, is thus a central focus of behavioural ecology. Our collaborative project aims for answering the questions how under natural conditions information transfer among group members leads to group coordination, using the communally breeding Bechstein’s bat, Myotis bechsteinii, as a model. Bechstein’s bat colonies show fission-fusion behaviour, i.e., splitting into subgroups and re-merging of subgroups, which switch their communal day roosts almost daily. Colony members coordinate their collective movements between roosts to ensure communal roosting, which provides them with grouping benefits such as social thermoregulation. Despite the importance of group coordination for the functioning of fission-fusion societies and the widespread occurrence of fission-fusion behaviour in bat colonies and other animal societies, only a few studies investigated information transfer and group coordination in wild fission-fusion societies. In this field study, we investigate how Bechstein's bat colonies coordinate their collective roost-switching. We use the recently established wireless biologging network BATS (Broadly Applicable Tracking System) to automatically collect data of nightly encounters of bats and their movements outside their roosts. In order to provide new insights in the coordination of collective roost-switching in bat colonies with high fission-fusion dynamics our study aims on identifying and quantifying the central behavioural elements that individuals use to find novel roosts and transfer information about communal roosts among each other (e.g., nightly approaches to roosts, leading-following behaviour, swarming behaviour). With the help of a field experiment we aim on assessing the flexibility of the coordination process, in particular with respect to the type of roost (familiar vs. novel roost) and the traits of the individuals involved (e.g., age, experience, kinship). Our project can build upon fully established field sites that are home to two Bechstein's bat colonies. These colonies have been monitored for up to 27 consecutive summers. All colony members are individually marked with PIT-tags and the bats’ demography and genetic relationships have been resolved. The significance of the project arises from the combination of a new cutting-edge technology (BATS- system) with an extraordinary long-term field data set on a bat species which has the potential to serve as a model for fission-fusion dynamics and group coordination behaviour. Our overarching goal is to improve the understanding of the functioning of animal societies with fission-fusion behaviour.