Scent marking meadow vole

Johnston, R.E., Sorokin, E.S. and Ferkin, M.H. (1997b) Scent counter-marking by male meadow voles females prefer the top-scent male. Ethology 103, 443 53. 

Much of the current data show that individuals spend different amounts of time self-grooming when they encounter particular opposite-sex conspecifics or their odors (Ferkin 2005, 2006 Ferkin and Leonard 2005). Thus, it is likely that an individual s age will also influence the amount of self-grooming. For instance, a study on meadow voles indicated that 12-13 mo old males spent more time than 2-3 and 8-9 mo old males investigating the scent marks of female conspecifics (Ferkin 1999). This study also found that and 8-9 mo-old female voles spent more time investigating the scent marks of 12-13 mo-old males than those of 8-9 mo-old and 2-3 mo-old males younger males (Ferkin 1999). These findings suggest that older male voles may be more interested in and attractive to females as compared... 

F erkin and Johnston (1995 a) aged anogenital area scent and odor from the posterolateral region in meadow voles Micmtuspennsylvanicus) for 15 minutes to 30 days. Males preferred female to male anogenital odor if it was 10 days old or less. Females preferred male to female anogenital odor if its age was 25 days or less. Both sexes preferred posterolateral odor of males to that of females if it was up to 1 day of age. In a second experiment, both sexes preferred fresh odors from either source over the same scents that were older. In conclusion, information about sex may get lost with the age of the scent mark. 

If rivals are successfully chased from a territory the resident reduces the attraction of any scent marks deposited by those rivals with the addition of his own scent close to ( countermarking , e.g. house mice) or across ( overmarking , e.g. golden hamsters and meadow voles) those of the intruder (Johnston et al., 1994, 1997 Hurst and Rich, 1999 Hurst et al., 2001). The ability to ensure one s own scent marks are the most recent in the territory, by rapidly countermarking or overmarking all non-self marks, will signal competitive success as only males able to evict rivals could maintain such territorial signals. 

Johnston, R. E., Sorokin, E. S., and Ferkin, M. R, 1997, Scent counter-marking female meadow voles discriminate individual s marks and prefer top-scent males, Anim. Behav. 54 679-690. 

Male hamsters discriminate between female vaginal secretions deposited 24h apart (Johnston Schmidt 1979) and meadow voles respond more strongly to fresh compared to one day old anogenital scents (Ferkin, Burda, O Connor Lee 1995), but age differences are not necessary for either hamsters (Johnston et al 1995) or meadow voles (Johnston et al. 1997b) to discriminate between scent marks and counter-marks if these physically overlap, at least in part. However, our preliminary experiments with wild house mice suggest that an age difference in scents is necessary for female mice to discriminate between the urinary scent marks and counter-marks of competing males. We found that females discriminated in... 

Male hamsters are very sensitive to the physical overlap of scent marks from two potential mates (Johnston et al. 1995 Wilcox Johnston 1995 Johnston this volume). If males repeatedly encounter scent marks from two females, they will selectively remember only the odor of the top scent mark if the scents partially overlap but remember both if the marks do not overlap. They do this even if there is no appreciable age difference between the two overlapping marks or if the bottom mark is larger than the top mark. Further experiments have shown that they appear to detect interruptions in the track of the bottom mark (see Johnston Bhorade this volume). Female meadow voles also appear to detect the physical overlap of anogenital scents from two males (Johnston et al. 1997b Ferkin this volume). 

Ferkin, M. H., Dunsavage, J. Johnston, R. E. 1998. What kind of information do meadow voles, Microtus pennsylvanicus, use to distinguish between the top and bottom scent of an over-mark Anim. Behav., in press. 

The first hypothesis states that voles respond to the scent marks of same-sex conspecifics by over-marking and adjacent-marking the scent marks of same-sex conspecifics. This hypothesis predicts that voles will over-mark the scent marks deposited by a same-sex conspecific, thereby insuring that they are viewed as the top-scent donor in an area. This hypothesis is tested by reviewing two studies on meadow voles, one by Johnston et al., (1997a) and the other, a recently completed study in my laboratory (Ferkin, unpublished data). 

MEADOW VOLES OVER-MARK AND ADJACENT-MARK THE SCENT MARKS OF CONSPECIFICS AND DO MALES AND FEMALES DIFFER IN THESE RESPONSES ... 

One study on meadow voles tested the hypothesis that voles over-mark the scent marks of conspecifics (Johnston et al., 1997a). In that study, a male meadow vole (intruder) was released into the empty cage of a conspecific male (resident). The intruder male over-marked 83% of the resident male s scent marks, and used most of its scent marks as over-marks. These results support the hypothesis that male meadow voles overmark the scent marks of conspecific males. However, Johnston et al., (1997a) did not examine over-marking and adjacent-marking by female meadow voles. 

In the other study, I tested the hypothesis that male and female meadow voles overmark and adjacent-mark the scent marks of a same-sex conspecific (Ferkin, unpublished data). Briefly, two same-sex conspecifics were released sequentially into a large arena. The first vole was placed into a clean, large arena (90 x 60 x 30 cm), allowed to deposit its scent marks for 15 minutes, and then removed. Another vole, the second vole, was then... 

The results of this study (Ferkin, unpublished data), support the first hypothesis in that the second male and the second female meadow vole over-marked and adjacent-marked the scent marks of the first vole. Interestingly, the results did not support the second hypothesis that over-marking and adjacent-marking would be displayed more by male than by female meadow voles. The first female had roughly 35% of its scent marks overmarked and about 47% of its scent marks adjacent-marked by the second female. The first male had 15% of its scent marks over-marked and about 32% of its scent marks adjacent-marked by the second male. The results also showed that the second female used a greater proportion of its scent marks than the second male to over-mark and adjacent-mark the scent marks of the first vole. The second female used approximately 43% of its scent marks as adjacent-marks and about 21% of its scent marks to over-mark the scent marks of the first female. The second male used about 19% of its scent marks as adjacent-marks and only 5% of its scent marks as over-marks of the first male. In addition, the first female s scent marks received more over-marks and adjacent-marks than did those of the first male. 

Why do female meadow voles frequently over-mark and adjacent-mark the scent marks of conspecifics Female meadow voles are territorial (Madison McShea, 1987). Female voles may need to over-mark and scent mark frequently to insure that they can sig-... 

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