Many terrestrial mammals, including voles, self-groom when they encounter odors of opposite-sex conspecifics. Voles also spend different amounts of time self-grooming when they are exposed to odors of reproductively active and reproductively quiescent opposite-sex conspecifics, suggesting that self-grooming may be involved in the behaviors that support reproduction. If self-grooming is affected by the reproductive condition of the donor and the groomer, it is also likely that their ages will influence the amount of time that the groomer will self-groom. The objective of this paper was to test the hypothesis that age of the groomer and the scent donor affects the amount of time that meadow voles, Microtus pennsylvanicus, spend self-grooming when exposed to bedding scented by opposite-sex conspecifics. Older males (12-13 mo-old) spent more time self-grooming than younger males did (2-3 mo-old and 8-9 mo-old) when they were exposed to odors of 2-3 mo-old and 8-9 mo-old female voles. Younger males spent similar amounts of time self-grooming in response to odors of 2-3 mo-old, 8-9 mo-old, and 12-13 mo-old female voles. Female voles, independent of their age, spent more time self-grooming in response to odors of 12-13 mo-old males relative to 2-3 mo-old and 8-9 mo-old males. These data demonstrate that voles discriminate between the odors of different age opposite-sex conspecifics and adjust the amount of time they self-groom when exposed to them. The data augment the view that self-grooming is a specialized form of olfactory communication between the sexes.
