Attractiveness of Opposite-Sex Odor and Responses to It Vary with Age and Sex in Meadow Voles (Microtus pennsylvanicus)

Current models suggest that among short-lived mammals, such as rodents, older adults are less attractive to the opposite sex and spend less time associated with the opposite sex than do younger adults. The objective of this study was to test two hypotheses in three different age groups of meadow voles. The first hypothesis is that 3- to 5 month old voles produce scents that are more attractive to opposite sex conspecifics than those of 7- to 12 month old and 14- to 18 month old voles. The second hypothesis is that 3- to 5 month old voles spend more time than either 7- to 12 month old or 14- to 18 month old voles investigating the scents of an opposite sex conspecific. The first experiment shows that when choosing between two conspecifics, females prefer the odor of the older male within each pair and that males prefer the odor of the 7- to 12 month old females to those of either 3- to 5 month old or 14- to 18 month old females. Thus, the data did not support the first hypothesis. The second experiment shows that the 14- to 18 month old males spent more time investigating female odors than did either the 3- to 5 month old or 7- to 12 month old males and that 7- to 12 month old females spent more time investigating male odors than did the 3- to 5 month old and 12- to 18 month old females. These data did not support the second hypothesis. Overall, older adult male meadow voles are more interested in and attractive to females than are younger adult males. The present data raise questions as to whether current models predict the age-related effects on the behavior of short-lived mammals.