Effects of acute corticosterone treatment on partner preferences in male and female zebra finches (Taeniopygia guttata)

• Acute corticosterone treatment increases opposite-sex over same-sex preference in males.
• Corticosterone had no effect on opposite-sex preference over same-sex preference in females.
• At baseline, zebra finches preferred the same-sex group over a member of the opposite sex.
• Acute corticosterone increased opposite-sex preference over a same-sex group in both sexes.
• Acute corticosterone can shift the naturally occurring preferences in zebra finches.

Stress alters physiology and behavior across species. Most research on the effects of stress on behavior uses chronic stressors, and most are correlational. The effects of acute stressors on physiology and behavior have been mixed. Here, we use zebra finches, a highly gregarious species that forms long-term pair bonds, to test the effects of an acute corticosterone (CORT) on opposite-sex partner preferences over a same-sex individual or a group (the latter is a highly appealing option). We had two competing hypotheses. First, we predicted that acute CORT would alter preferences for the opposite sex bird in both conditions in both sexes. However, since there is a sex difference in the effects of CORT on partner preferences in voles, these effects may be more pronounced in males than in females. To test our hypotheses, we administered 2 doses of CORT (10 μg and 20 μg) or vehicle (control) using a repeated measures design. In the male vs. female test, there was a significant Sex by Treatment interaction, such that in males, 10 μg CORT increased preferences for a female over the male compared to when these same males were treated with saline at baseline. There were no effects of treatment in females. In the opposite-sex vs. group condition, there was an overall effect of Treatment, such that the 10 μg dose increased preference for the opposite-sex individual over both saline treatments, regardless of sex. These findings further our understanding of the effects of an acute stressor on sexual partner preferences.