Scent Over-Marking and Adjacent-Marking as Competitive Tactics Used During Chemical Communication in Voles

Abstract

This chapter reviews studies on meadow voles and prairie voles that test the broad hypothesis that over-marking, a phenomenon in which an individual places its own scent on top of the scen mark of a conspecific, is a competitive tactic that provides advantages in the transfer of chemical information to the top-scent donor but not to the bottom-scent donor of an over-mark. To establish whether over-marking is a competitive tactic, four specific hypotheses were tested. One, voles over-mark the scent marks of same-sex conspecifics. Two, male voles over-mark the scent marks of same-sex conspecifics more than female voles do. Three, voles over-mark the scent marks of age-matched, unfamiliar, nonsiblings more than those of familiar siblings. Four, individuals investigating areas containing over-marks respond preferentially to the odor of the vole whose scent is on top, but not to that of the vole whose scent is on the bottom. The reviewed data support the first, third, and fourth hypotheses, but do not support the second hypothesis. Overall, the findings indicate that 1) investigating animals attach a greater value to the odor of the topscent donor than that of the bottom-scent donor and 2) over-marking and adjacent-marking may be used by voles as competitive tactics.