Chemical characterisation of potential pheromones from the shoulder gland of the Northern yellow-shouldered-bat, Sturnira parvidens (Phyllostomidae: Stenodermatinae).

Chris G. Faulkes,Nancy B. Simmons,Brock Fenton,Elizabeth L. Clare,David A. Baines,J. Stephen Elmore

doi:10.7717/peerj.7734

Abstract

Bats of the genus Sturnira (Family Phyllostomidae) are characterised by shoulder glands that are more developed in reproductively mature adult males. The glands produce a waxy secretion that accumulates on the fur around the gland, dyeing the fur a dark colour and giving off a pungent odour. These shoulder glands are thought to play a role in their reproductive behaviour. Using gas chromatography–mass spectrometry, we analysed solvent extracts of fur surrounding the shoulder gland in the northern-shouldered bat, Sturnira parvidens to (i) characterise the chemical composition of shoulder gland secretions for the first time, and (ii) look for differences in chemical composition among and between adult males, sub-adult/juvenile males and adult females. Fur solvent extracts were analysed as liquids and also further extracted using headspace solid-phase microextraction to identify volatile components in the odour itself. Odour fingerprint analysis using non-metric multidimensional scaling plots and multivariate analysis revealed clear and significant differences (P < 0.001) between adult males vs both juvenile males and adult females. The chemical components of the shoulder gland secretion included terpenes and phenolics, together with alcohols and esters, most likely derived from the frugivorous diet of the bat. Many of the compounds identified were found exclusively or in elevated quantities among adult (reproductive) males compared with adult females and non-reproductive (juvenile) males. This strongly suggests a specific role in male–female attraction although a function in male–male competition and/or species recognition is also possible.

Highlights

IntroductionPheromones are intra-specific semiochemicals (chemical signals) that modify the behaviour and/or physiology in the recipient animal
Pheromones are intra-specific semiochemicals that modify the behaviour and/or physiology in the recipient animal
Chemical cues are known to be used by big brown bats Eptesicus fuscus (Bloss et al, 2002), and implicated in Bechstein’s bats, Myotis bechsteinii (Safi & Kirth, 2003) and the fisherman bat, Noctilio leporinus (Brooke & Decker, 1996)

Summary

Introduction

Pheromones are intra-specific semiochemicals (chemical signals) that modify the behaviour and/or physiology in the recipient animal. There are two general categories of semiochemicals within a species: pheromones, chemical signals which elicit a stereotypical behavioural or physiological response in the recipient animal, while signature mixtures are odour cues which are learned by the conspecific receivers and often have complex and variable chemical profiles. These ‘individual mixtures’ or ‘signature odours’, which act in social communication though learning may identify a specific individual or social group (Wyatt, 2014, 2017; Dehnhard, 2011). Chemical cues are known to be used by big brown bats Eptesicus fuscus (Bloss et al, 2002), and implicated in Bechstein’s bats, Myotis bechsteinii (Safi & Kirth, 2003) and the fisherman bat, Noctilio leporinus (Brooke & Decker, 1996)

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