Length polymorphism at the avpr1a locus is correlated with male reproductive behavior in a natural population of prairie voles (Microtus ochrogaster)

Effects of avpr1a length polymorphism on male social behavior and reproduction in semi‐natural populations of prairie voles (Microtus ochrogaster)

“…Consistent with this hypothesis is evidence from a study by Keane et al. () that found a relationship between male reproduction and avpr1a genotype in an Indiana population only when considering the males with the longest and shortest avpr1a microsatellite allele lengths.…”

“…In the laboratory study by Hammock and Young () that reported that male avpr1a microsatellite allele length predicted some male social behaviors, they compared the behaviors of males that were homozygous for avpr1a microsatellite alleles that were shorter than the average length to that of males homozygous for alleles longer than the average length. The failure of all previous studies to detect evidence that male avpr1a microsatellite allele length influences male social behavior in a field setting (Keane et al., ; Mabry et al., ; Ophir et al., ; Solomon et al., ) may have been due in part to males homozygous for two short or long avpr1a microsatellite alleles being relatively uncommon. We thought we could enhance our ability to detect an influence of male avpr1a microsatellite allele length on male social behavior in a field setting, where other variables may mask the influence of avpr1a length, by examining the behavior of males possessing two avpr1a microsatellite alleles that were much shorter or longer than the average length, similar to the study by Hammock and Young ().…”

“…These results seem counterintuitive as IL males with short avpr1a alleles tended to overlap the home ranges of more females, were less likely to be residents, and formed weaker pair bonds with their social partner in laboratory studies (Hammock & Young, ) compared to IL males with long a vpr1a alleles. Perhaps a greater female mating preference for males with long a vpr1a alleles (Castelli et al., ; Keane et al., ) negated the differences in space use and pair bonding between males with short versus long avpr1a microsatellite alleles, resulting in less genetic monogamy among males long a vpr1a alleles. Unlike the IL males, there was no difference between KS males with long versus short avpr1a microsatellite alleles in genetic monogamy.…”

“…In a three‐year study of natural populations of prairie voles in Kansas and Indiana, social and genetic monogamy was found to be more common in the Kansas population (Streatfeild et al., ), but no significant relationships between male microsatellite allele length at the avpr1a locus and indices of social and genetic monogamy were detected in either population (Mabry et al., ). However, a later study of the same Indiana population in which the field season was approximately 3.5x longer showed that males with the longest avpr1a microsatellite allele lengths were significantly more likely to sire offspring with more than one female and to sire more offspring that survived until trappable age than males with the shortest avpr1a microsatellite allele lengths (Keane, Parsons, Smucker, & Solomon, ). There was also no evidence that the microsatellite allele length at the avpr1a locus of male prairie voles predicts variation in several behavioral indices of social monogamy such as space use or the likelihood of a male adopting a resident versus wanderer (male found at >1 nest) reproductive tactic in studies of semi‐natural populations by Ophir et al.…”

“…Most of these studies suggest that avpr1a microsatellite length polymorphism may not be an important factor contributing to individual differences in displays of social monogamy, and possibly also genetic monogamy, under field conditions. In the Indiana population in which a significant influence of avpr1a microsatellite allele length on male reproductive success was detected, the significant difference was between males with the longest and shortest summed avpr1a microsatellite lengths (Keane et al., ). This result suggested that a comparison of males with extreme avpr1a lengths may provide better test of the hypothesis that avpr1a microsatellite allele length plays a role in mediating social and genetic monogamy.…”