Does low fecundity reflect kin recognition and inbreeding avoidance in the mandarin vole (Microtus mandarinus)?

Abstract

The effects of kin recognition on estrus and breeding in mandarin voles (Microtus mandarinus) were investigated in the laboratory using a cross-fostering method. Nonsiblings reared apart produced significantly more litters than siblings or nonsiblings reared together. These results may support the hypothesis that familiarity through association before weaning plays an important role in kin recognition. On the other hand, nonsiblings reared apart produced significantly more litters than siblings reared apart. Furthermore, there was no significant difference in number of litters between siblings reared apart and siblings reared together. These observations show that phenotype-matching mechanisms of kin recognition may operate in conjunction with familiarity in kin recognition in this species. Through observing the vaginal cytology of female mandarin voles paired with different males in different rearing conditions, it was found that females paired with familiar males (through association before weaning) produced significantly fewer estrous smears than females paired with unfamiliar males (reared by different parents before weaning), regardless of genetic relatedness. Thus, using vaginal cytology as an indicator of estrus, it was found that familiarity through association before weaning may retard the first estrus of female mandarin voles.