Mating system and copulatory behavior of the greater mouse-eared bat (Myotis myotis).

Mammalian mating systems, which form the cornerstone of social systems, are shaped by diverse ecological and sociobiological factors, and they influence behavior and reproductive success. Among mammals, bats exhibit a remarkable diversity of mating systems, making them ideal for studying their complexity; yet, interspecific variations of bat mating systems remain largely unknown. To address this, we surveyed six roosts of the greater mouse-eared bat (Myotis myotis) over 2 years, uncovering novel aspects of their mating system. Our findings suggest a lek mating system, where males aggregate and are visited by receptive females. Mating involves multiple copulations and distinct body postures, with the female remaining with the male for several hours. Male roost occupancy peaked in August, reflecting a phenological cycle. Males demonstrated pronounced territoriality and site fidelity, defending display spots with vocalizations and physical confrontations, underscoring their important role in securing mating success. Complex vocalizations appeared crucial for deterring rivals and attracting females, suggesting vocal signals govern mate choice by females. Additionally, a yellow facial secretion observed in males may function as an olfactory signal during mate selection. This study provides valuable insights into the mating system of M. myotis, with implications for understanding the species' behavioral ecology and contributing to conservation strategies.