The effect of pair bonding in Cabrera vole’s scent marking

The Cabrera vole (Microtus cabrerae) is a rare rodent living in patchy grassy areas of the Iberian Peninsula where unpaired individuals of both sexes use scent marking primarily to increase their mate-finding likelihood. Cabrera voles establish long-term pair bonds with opposite-sex conspecifics constituting a breeding pair, which is expected to reduce the efforts in searching for a new mate. Under such circumstances, scent marking as a strategy to increase mate-finding likelihood became useless. Accordingly, we hypothesise that pair bonded Cabrera voles suppress mate-finding scent marking to reduce energetic costs and predation risk. To test this hypothesis, we compared scent-marking behaviour towards a clean substrate, in both paired and non-paired voles. No differences were found in the scent marks’ type and the amount of marks placed by voles in both conditions. We also analysed the scent-marking behaviour of both sex pair bonded voles when exposed simultaneously to a clean substrate, a substrate pre-marked by males and a substrate pre-marked by females. We found no significant differences in scent-marks (urine-marked area and number of faecal boli) across the three types of substrate types. In accordance with our prediction, these results suggest that pair bonded Cabrera voles did not use scent marking for mate finding, thus providing further support to the existence of a monogamous mating strategy. Furthermore, our results fail to support the use of scent marking for territorial defence purposes