Foraging flight strategy varies with species identity of co-occurring individuals in bats

Foraging is a key function in the animal kingdom. Foraging in groups drives food patch discovery through social information transfer that maximizes an individual's foraging success through either cooperation or competition in response to congener presence. Understanding how congener presence affects the foraging strategy is especially challenging as it requires close monitoring of animal movements, foraging success, and competitive interactions. The consequences of congener presence on the foraging flight strategy of bats, a highly social taxon with strong behavioral plasticity in response to resource ephemerality, remain little tested. Through a 3D acoustic tracking of individual echolocation calls, we assessed to which extent foraging flight strategy of bats varied in response to conspecific and heterospecific presence. We found that flight speed, the main lever for adjusting energy balance during foraging (ie slowing down to capture prey and speeding up to find new prey patches), is no longer used in the presence of intra-guild heterospecifics. Also, the overall foraging level increased regardless of co-occurring species, through a facilitation and/or a higher prey availability. The study shows that bats integrate species identity in making decisions about their foraging flight strategy, with a stronger tolerance toward conspecifics with which social relations are most important, eg because they share the same roost. This might have important implications in understanding the consequences of interactions, especially in relation to anthropogenic pressures that rearrange bat communities and their prey in time and space, which could exacerbate natural competition.