Sternal Gland Scent-Marking Signals Sex, Age, Rank, and Group Identity in Captive Mandrills

Abstract

Mandrills are one of the few Old World primates to show scent-marking. We combined ethological and chemical approaches to improve our understanding of this behavior in 3 zoo-managed groups. We observed the olfactory behavior performed by adults and adolescents (N = 39) for 775h. We investigated the volatile components of sternal scent-marks using gas chromatography-mass spectrometry and compared volatile profiles with traits of the signaler. Males marked more than females and within each sex the frequency of scent-marking was related to age and dominance status, but alpha males scent-marked most frequently and particularly in specific areas at the enclosure boundaries. We identified a total of 77 volatile components of sternal gland secretion, including compounds functioning as male sex pheromones in other mammals, in scent-marks spontaneously released on filter paper by 27 male and 18 female mandrills. We confirmed our previous findings that chemical profiles contain information including sex, male age and rank, and we also found that odor may encode information about group membership in mandrills. Our results support the hypotheses that scent-marking signals the status of the dominant male as well as playing territorial functions but also suggest that it is part of sociosexual communication.

Normalizing Gas‐Chromatography–Mass Spectrometry Data: Method Choice can Alter Biological Inference

“…Identifying whether or not chemo‐sensory signals/cues differ between groups of interest is a major component of GC‐MS research . From simulation study 1, we found that when differences between groups were pronounced, and the structure of the underlying data was relatively simple, all methods resulted in comparable model performance.…”

“…Information in these ‘odors’ can be encoded either digitally through the presence/absence of individual compounds, and/or analogically through their relative abundance . Their composition varies with primary gland products, secondary metabolites from commensal microbiota, and environmental factors, and can therefore convey a wide range of individual‐specific information such as age, sex, diet, disease status, reproductive state, and genotype …”

Multimodal pair‐bond maintenance: A review of signaling across modalities in pair‐bonded nonhuman primates

“…Chemical signals are excreted in saliva, urine, feces, or from sternal, anogenital, subcaudal, or cutaneous scent glands, frequently through scent‐marking behavior (Drea, 2015; Zhang et al, 2009). Chemical signals may relay information about individual identity, age, sex, hormonal condition, genetic quality, immune function, and/or social status, although studies suggest that the informational content likely differs by species (e.g., Charpentier, Boulet, & Drea, 2008; Epple, Golob, Cebul, & Smith III, 1981; Hayes, Morelli, & Wright, 2004; Vaglio et al, 2015). Because scent is a longer‐lasting form of communication, these signals have the potential to provide information to unwanted receivers who pass by later, such as predators (that can use scent marks to track prey) or rival conspecifics (that may attempt to invade a pair's territory; Zhang et al, 2009).…”

The origins of gestures and language: history, current advances and proposed theories

“…Innocenti et al ., ), chemical properties [e.g. scent secretions (Chen & Haviland‐Jones, ; Palagi & Dapporto, ; Vaglio et al ., )] and statistical patterns [Zipf's law of abbreviation and Menzerath's law (e.g. Gustison et al ., ; Heesen et al ., )].…”