Social vocalizations of big‐footed myotis (Myotis macrodactylus) during foraging

Abstract

Acoustic signals play a crucial role in transmitting information and maintaining social stability in gregarious animals, especially in echolocating bats, which rely primarily on biological sonar for navigating in the dark. In the context of foraging without relying on tactile, visual or olfactory cues, acoustic signals convey information not only on food but also on ownership and defense of resources. However, studies on such information remain fragmentary. In the present study, we aim to document the social vocal repertoire of Myotis macrodactylus at natural foraging sites. Multiple acoustic analyses and spectrographic classification revealed a rich foraging vocal repertoire comprising 6 simple syllables and 2 composites. Discriminant function analyses associated with a subset‐validation procedure provided an optimal method to spectrographically classify all recorded sounds into different syllable types. Multidimensional scaling of median values of multiple parameters further confirmed notable differences among these syllables in a 3‐D space. In addition, Euclidean distance analysis showed that there were some spectral similarities between specific social vocal syllables and feeding buzzes, which implied a potential jamming role. Altogether, the data indicate that bats at foraging sites under natural conditions used variant social vocalizations with different functions in addition to echolocation calls, providing supporting evidence for further work on the function and vocal mechanisms of acoustic communication in mammals.

Foraging fidelity and individual specialization in a temperate bat Myotis Nattereri

“…foraging; with dominant individuals choosing and maintaining their preferred locations whilst sub-dominant bats may be left with less productive foraging choices. Food defence via social calls has been described in Eptesicus fuscus(Wright et al, 2014), Vespertilio sinensis(Luo et al, 2017) and Myotis macrodactylus(Guo et al, 2019), supporting the idea of bat social hierarchies. In addition, male Hipposideros armiger have been found to emit varying social calls correlating to information about body mass, dominance rank and individual identity.…”

“…Recently, the idea of bats exhibiting foraging site delity has been extended, to suggest that it may be a result of the territorial defence of feeding areas through the use of social calls (Gadziola et al, 2012;Götze et al, 2020;Guo et al, 2019;Luo et al, 2017). Territorial defence of feeding areas is thought to minimize feeding competition (Wrangham, 1979), maximize feeding e ciency through familiarity with the distribution of food resources (Hillen et al, 2009;Pusey et al, 1997), or directly impact reproductive success (Thompson et al, 2007).…”