Males are more sensitive to their audience than females when scent-marking in the redfronted lemur

Abstract

Audience effects, i.e. changes in behaviour caused by the presence of conspecifics, have rarely been studied in the context of olfactory communication, even though they may provide important insights into the functions of olfactory signals. Functional sex differences in scent-marking behaviours are common and influenced by the social system. To date, patterns of functional sex differences in scent-marking behaviours remain unknown in species without overt dominance relationships. We investigated sex differences in intra-group audience effects on anogenital scent-marking in a wild population of redfronted lemurs (Eulemur rufifrons) by performing focal scent-marking observations. With a combination of generalised linear mixed models and exponential random graph models, we found different audience effects in both sexes. Males were overall more sensitive than females to their audience. Only males seemed to be sensitive to the presence of both members of the opposite sex and same-sex conspecifics in the audience. Females were only moderately sensitive to the presence of other females in the audience. This study offers a potential behavioural pattern associated with anogenital scent-marking that seem to differ from those described for species exhibiting female dominance, supporting the notion that the social systems co-varies with scent-marking behaviours and scent-complexity in strepsirrhines.