Evaluating odour and urinary sex preferences in the big brown bat (Eptesicus fuscus)

Abstract

Olfactory cues provide detailed information to mammals regarding conspecifics. Bats may identify species, colony membership, and individual’s using olfaction. Big brown bats (Eptesicus fuscus (Palisot de Beauvois, 1976)) live in mixed-sex colonies and must differentiate between sexes to locate mates. We hypothesized that odour cues convey information about sex. In Experiment 1, adult E. fuscus were recorded exploring a Y-maze that contained general body odours sampled from male or female conspecifics. One group of subjects was habituated to the Y-maze prior to experimental trials, whereas a second group was not. Bat exploration and the proportion of time spent near each scent were used as preference indicators for the body odour of a particular sex. Experiment 2 followed similar procedures except the odour cue tested was urine from either male or female conspecifics and without Y-maze habituation. Results found no evidence that E. fuscus prefer the body odours of a given sex, but females did prefer the odour of male urine. Non-habituated animals in Experiment 1 were more likely to explore the Y-maze and approach a stimulus scent compared to habituated bats. These findings have important implications for courtship and mating behaviour in bats, as well for designing future behavioural studies.

Common insecticide affects spatial navigation in bats at environmentally-realistic doses

“…The Y-maze is one of the simplest methods for assessing animal cognition and does not require rule learning, extensive handling or repeated manipulation [32]. The Y-maze test has been used extensively in learning and memory paradigms for rodents (Arendash et al, 2001;Conrad et al, 1997;King & Arendash, 2002;Lainiola et al, 2014;Ma et al, 2007), fish (reviewed in Cleal et al, 2020) and bats [34][35][36][37][38]. Flight is, perhaps, the most common natural movement in bats, though many vespertilionid bats like E. fuscus are adept at crawling on surfaces when locating suitable roosts and exploring crevices and cavities [39].…”

Social Communication in Big Brown Bats

“…Yet, there is no evidence of big brown bat pups choosing the scent of their mother over the scent of other females ( Mayberry and Faure, 2014 ). There is also no evidence that big brown bats distinguish between sexes based on olfactory cues, so it is believed that big brown bats use olfactory cues mainly to differentiate between colonies, not individuals ( Greville et al, 2021 ). The colony scent differences could be due to the environment, such as the microbiota or microclimate of the hibernacula, or due to common food resources ( Greville et al, 2021 ).…”