Meeting Abstract
Understanding the significance of individual variation in hormone levels and behavior is an important goal for behavioral endocrinologists as variation in behavior is often associated with reproductive success. Manakins are known for performing complex courtship displays at leks and these complex displays have evolved in association with strong reproductive skew, suggesting individual differences in courtship behavior exist. Furthermore, male wire-tailed manakins (Pipra filicauda) exhibit male-male cooperative displays and variation in this cooperative behavior has been found to be predictive of a male’s probability of acquiring a territory and siring offspring. Our previous research has shown that territory-holding males have higher testosterone than floaters (i.e., non-territory-holding males), implying that testosterone plays a role in territory acquisition and maintenance. For the current study we quantified individual male courtship and cooperative behavior and subsequently collected a blood sample to measure testosterone concentrations. Our results show that males with a higher proportion of cooperative displays perform longer displays. However, males with high circulating testosterone engage in fewer cooperative display bouts suggesting that high levels of testosterone may interfere with effective cooperative behavior and result in shorter display bouts. These results suggest that individual differences in circulating testosterone levels play an important role in mediating individual variation in male reproductive behavior and potentially success. This research ultimately adds to our knowledge about the proximate mechanisms that mediate individual variation in both reproductive and cooperative behavior.
