Sex differences in olfactory social recognition memory in meadow voles, Microtus pennsylvanicus

• Published in: Ethology 2020-10, Vol.126 (10), p.993-1003
• Main Authors: Clark, Kelsey E., Messler, Kaitlynn A., Ferkin, Michael H., Ebensperger, Luis
• Format: Article
• Language: English
• Subjects: Animal behavior; Anogenital; Breeding success; conspecific; Conspecific odors; Conspecifics; Exposure; Females; Gender aspects; Gender differences; Genotypes; Habituation; Habituation (learning); individual discrimination; Intervals; meadow voles; Meadows; memory; Microtus; Microtus pennsylvanicus; Odor; Odors; olfaction; Recognition; Reproduction; Reproductive fitness; Scent marking behavior; Scents; Sex; Sex differences; Social interactions; Terrestrial environments
• ISSN: 0179-1613; 1439-0310
• DOI: 10.1111/eth.13074

Terrestrial mammals, like rodents, use odors, and scent marks to indicate their presence in an area to conspecifics. These odors convey information about the scent donor's genotype, sex, condition, and age. The ability to discriminate among the scent marks of conspecifics and later recollect the identity of the donor is essential for choosing between familiar and unfamiliar mates. We tested the hypothesis that the promiscuous meadow vole (Microtus pennsylvanicus) can recollect the odor of a familiar, opposite‐sex conspecific and distinguish it from that of an unfamiliar, opposite‐sex conspecific. We also hypothesized that because reproductive success is highly skewed among male meadow voles and competition for mates is intense, males will be more likely than females to recollect the odor of a familiar, opposite‐sex conspecific and distinguish it from that of an unfamiliar, opposite‐sex conspecific, for a longer period of time. Using a habituation task, we first exposed the voles, 4 times successively, to the anogenital area scent of an opposite‐sex conspecific. Then, 1 hr, 24 hrs, 72 hrs, or 96 hrs after the fourth exposure, voles were presented with the odor of the donor from the exposure phase (familiar donor) and that of an unfamiliar, opposite‐sex conspecific. Female meadow voles spent similar amounts of time investigating the scent of the familiar male donor and that of an unfamiliar male donor after the 1‐hr and 24‐hr intervals. Male meadow voles, however, spent more time with the scent of an unfamiliar female donor than that of the familiar female donor after the 1‐hr, 24‐hr, and 72‐hr intervals, suggesting that male voles could recollect the scent mark of a familiar female for at least three days. The implications of these sex differences in social memory may reflect the different strategies male and female meadow voles use in the recognition of previous and potential mates. Recognition of an individual's scents may enhance fitness by allowing animals to direct appropriate behaviors toward those individuals. Mean ± SEM time (seconds) spent by female meadow voles (n = 12) investigating the anogenital area scent from male conspecifics during the habituation phase (H1, H2, H3, H4 habituation trials) and 1 hr later, during the test phase (F = familiar scent donor; UN = unfamiliar scent donor). ns = not significant, *p