Abstract
Sexual selection theory predicts that females should prefer males with the most intense courtship displays. However, wing-spread song displays that male brown-headed cowbirds (Molothrus ater) direct at females are generally less intense than versions of this display that are directed at other males. Because male-directed displays are used in aggressive signaling, we hypothesized that females should prefer lower intensity performances of this display. To test this hypothesis, we played audiovisual recordings showing the same males performing both high intensity male-directed and low intensity female-directed displays to females (N = 8) and recorded the females' copulation solicitation display (CSD) responses. All eight females responded strongly to both categories of playbacks but were more sexually stimulated by the low intensity female-directed displays. Because each pair of high and low intensity playback videos had the exact same audio track, the divergent responses of females must have been based on differences in the visual content of the displays shown in the videos. Preferences female cowbirds show in acoustic CSD studies are correlated with mate choice in field and captivity studies and this is also likely to be true for preferences elucidated by playback of audiovisual displays. Female preferences for low intensity female-directed displays may explain why male cowbirds rarely use high intensity displays when signaling to females. Repetitive high intensity displays may demonstrate a male's current condition and explain why these displays are used in male-male interactions which can escalate into physical fights in which males in poorer condition could be injured or killed. This is the first study in songbirds to use audiovisual playbacks to assess how female sexual behavior varies in response to variation in a male visual display.
Highlights
Visual displays involving motion are likely to be physiologically costly especially when performed repeatedly, as is often the case with the audiovisual (AV) courtship displays of many avian and other species
Sexual selection theory predicts that these types of energetically demanding displays will be used by females in mate choice because display vigor or skill, or both, could be an honest indicator of a male’s current physical condition, which is likely to be related to his genetic quality [1,2,3] and the quality of his parental care if such care is provided
In Experiment 2, we presented the same females with different AV recordings of low intensity female-directed displays played with and without an accompanying perched song audio track to determine whether the visual information alone in a wing-spread display elicits female copulation solicitation display (CSD) that are as strong as those elicited by AV playbacks
Summary
Visual displays involving motion are likely to be physiologically costly especially when performed repeatedly, as is often the case with the audiovisual (AV) courtship displays of many avian and other species. In theory, a female that chooses a mate based on his superior display performance should have higher fitness than a less choosy female because her offspring will inherit higher quality genes from their father. In these circumstances, males will be selected to produce display performances that optimize the trade-off between their mating success and the costs of the display (such as its effects on survival), and higher-quality males will produce the most physiologically demanding display performances. Male satin bowerbirds (Ptilonorhynchus violaceus) reduce the intensity of their courtship displays in response to the ‘startle’ reactions of females [4]. Male satin bowerbirds may not always display at the maximum intensity that they are capable of so as to avoid startling females and disrupting courtship
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
