Female Audience Shapes the Complexity and Syntax of Male Courtship Displays in a Lek-Mating Bird

AbstractCourtship displays of lek-mating Golden-winged Manakins (<i>Masius chrysopterus</i>) are context dependent. Presence or absence of a female audience and female behavior, more than male identity, determine variation in the constituent elements (repertoire) and ordering (syntax) of displays. We analyzed 422 display videos in three contexts: displays without audiences (SOLO; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>307</mml:mn></mml:mrow></mml:math>), displays for female audiences that did not end in copulation (AUDI; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>102</mml:mn></mml:mrow></mml:math>), and displays ending in copulation (COP; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>13</mml:mn></mml:mrow></mml:math>). Using entropy and a metric we call compressibility (ratio of compressed to uncompressed display strings), we found that ordering of elements (syntax) decreased in complexity from SOLO to AUDI to COP displays. Jaro string distance, a record-linkage metric for assessing string similarity, showed that display string syntax corresponded more to audience context than to performer identity. COP displays of individual males differed more from their own AUDI or SOLO displays than from the COP displays of other males. Males responded to female behavior-her consistent positioning downslope from him on the display log-with simple COP displays. Courtship displays of Golden-winged Manakins are dynamic interactions between females and males, depending more on male response to female audience behavior than on traits intrinsic to particular males.