Meeting Abstract

49.3  Saturday, Jan. 5  Environmental Modulation and Endocrinological Correlates of Same-Sex Affiliative Behavior in Female Meadow Voles ONDRASEK, N.R.*; WADE, A.C.; BURKHARD, T.; HSU, K.; NGUYEN, T.; POST, J.; ZUCKER, I.; University of California, Berkeley; University of Southern California; University of California, Berkeley; University of California, Berkeley; University of California, Berkeley; University of California, Berkeley; University of California, Berkeley

The prevalence of female-biased affiliations in group-living mammalian species suggests that same-sex relationships are of particular importance for females. However, little is known about the influence of environmental and physiological factors on same-sex social bonds. Female meadow voles present an interesting opportunity for the investigation of these questions because free-living females display seasonal variations in same-sex affiliation. As they transition from summer to winter, females transition from an aggressive, territorial phenotype to an affiliative, group-living phenotype. The thermometabolic advantages of huddling have been offered as an explanation for winter sociality in meadow voles; thus, we designed a study to assess the effects of ambient temperature, day length, food availability, and frequency of handling on same-sex affiliative behavior and several potential physiological correlates. In a separate study, group size and social preferences were evaluated in male and female meadow voles. Our findings suggest that: 1) day length, food availability, and ambient temperature interact to regulate same-sex affiliative behavior in female meadow voles; 2) low temperature exposure can modify social preferences without increasing huddling behavior; 3) differences in handling modulate plasma corticosterone and estradiol without modifying same-sex affiliation; 4) under certain environmental conditions, variations in same-sex affiliative behavior are correlated with plasma corticosterone and estradiol; and 5) the propensity to join a group consisting of novel individuals varies by day length and sex.