Meeting Abstract
P2.105 Saturday, Jan. 5 Differential courtship effort by mated and unmated males in a free-living songbird KIMMITT, A.A.*; REICHARD, D.G.; WELKLIN, J.W.; KETTERSON, E.D. ; Univ. of Mary Washington; Indiana Univ., Bloomington; Indiana Univ., Bloomington; Indiana Univ., Bloomington aakimmitt@gmail.com
Courtship displays that encompass multiple signaling modalities are utilized by males of many species to attract a potential mate. Females often prefer males that court using particular signals or intensities, yet males vary in their courtship characteristics and effort despite these preferences. In this study, we investigated whether mated males differed from unmated males in their courtship behavior or circulating hormone levels. We studied a songbird, the dark-eyed junco (Junco hyemalis), and presented free-living, males with a live, caged female conspecific. We stimulated the male to approach and court the female with playback of a female pre-copulatory trill, and we recorded each male’s acoustic and visual courtship response. Immediately following the trial, we captured the male to take measurements and collect plasma to measure testosterone (T) and corticosterone (CORT). We also restrained males for 15 min and bled them again to measure restraint-induced CORT levels. Mated males were found to approach the female more closely, be more active, sing less long-range song, and display visually at maximum levels for longer than unmated males. While mated males were also significantly larger than unmated males, age and multiple morphological measures did not significantly correlate with any courtship behaviors. Mated and unmated males may adjust their behavior according to context exhibiting differences in courtship dynamics used when establishing a pair bond (unmated males) as compared to when seeking an extra-pair copulation (mated males). Results of hormone assays are still pending. Collectively, our results suggest that of the characters we measured, mating status is the best predictor of male courtship effort in juncos.
