Meeting Abstract

86.1  Sunday, Jan. 6  Call timing preferences in gray treefrogs, Hyla versicolor HUMFELD, S. C.*; SCHWARTZ, J.; MARSHALL, V. T. ; University of Missouri; Pace University; University of Scranton humfelds@missouri.edu

In a variety of animal taxa, females often show preferences based on the relative timing of sexual advertisement signals produced by different males. Such preferences may be important selective forces on communication systems, leading to phenomenon such as synchronous displays or avoidance of overlap. In a preliminary study, we examined the preferences of female gray treefrogs for calls broadcast with different timing relationships. We systematically modified the interval between the onset of calls. At the longest intervals (900 and 500 ms), calls did not overlap but exhibited a distinctive leader-follower timing relationship. At the shorter delays (225 and 25 ms), calls overlapped in time. With the overlapping calls, we further experimented with pulse overlap, in which pulses were interleaved or overlapped so that pulses also exhibited leader-follower timing relationships. The results of two-speaker choice tests show that females increasingly preferred the leading call as the interval between signal onset was shortened, and this effect was more distinctive with shorter-than-average calls. However, this preference for a leading call could be reversed if the pulses of following calls were positioned in a leading position relative to the pulses of the other call. Finally, by testing calls of different durations, we conclude that the preference for leading calls was fairly weak compared to the preference for longer call duration. We discuss the possibility of significant geographic variation in this preference.