Foraging male particoloured bats use local enhancement and group facilitation during spermatogenesis

Social foraging is commonly used across taxa to increase animal foraging success in uncertain environments and is believed to be a driver of social group formation. In temperate zones, females of many bat species form seasonal colonies, whereas males are usually solitary. Males of only a few bat species form temporary colonies during sperm production, likely to benefit from social foraging, social thermoregulation, or both. We radiotracked a group of reproductive male particoloured bats, Vespertilio murinus, to test the hypothesis that they use social foraging. Foraging bats overlapped in time and space significantly more than expected by chance, suggesting that they used social information to increase detection of insect swarms. Dyads also sometimes switched foraging patches together, suggesting part-time use of the more coordinated group facilitation social foraging strategy. Our results support the hypothesis that male particoloured bats use local enhancement mixed with group facilitation during sperm production and that improved foraging success through information transfer is a likely driver of seasonal sociality in these and other male bats.