Meeting Abstract
Understanding the biological and physiological parameters associated with changes in animal health is critical for improving our insights into evolutionary processes associated with condition-dependent signaling. In mammals, complex olfactory ‘signatures’ communicate stable characteristics (species, sex, identity) to conspecifics, but can also be condition dependent, varying with health status, parasite load, and disease. The latter suggests that, like other signals, scent signals may be energetically expensive to maintain, with resources being diverted to recovery processes. Fundamental gaps in our understanding of the relationships between scent signals and host health, particularly in non-model, non-laboratory species, means that an olfactory version of the ‘expensive or honest signal hypothesis’ remains to be further tested. We investigated the effects of health (wellness, injury, illness) on chemical signals in the ring-tailed lemur (Lemur catta), a socially integrated, but highly aggressive, strepsirrhine primate. This species boasts a complex, sexually differentiated repertoire of scent-marking behavior, involving both stable and transient olfactory cues. We paired genital odorant composition (from gas chromatography-mass spectrometry analyses) with health status (from veterinary records) in 24 adult, captive L. catta across periods of wellness, injury/illness, and recovery. Scent signals became drastically ‘muted’ during the period of insult, showing significant decreases in chemical richness and diversity, and altered composition. Based on these results, we suggest that, when unwell, animals are unable to bear the costs of producing their normal olfactory signature. These changes are likely to be salient to conspecifics and could alter social behavior, group dynamics, and potentially mate choice. Funded by NSF IOS-0719003.
