Sources of Selection on Signal Timing in a Tree Frog


Gerlinde Höbel, Department of Biological Sciences, University of Wisconsin – Milwaukee, PO Box 413, Milwaukee, WI 53201, USA. E-mail:


Signal-timing adjustment is common in communally signaling species, and there is large variation in signal-timing formats found in nature. We conducted a survey of geographic variation in female signal-timing preferences and male signaling behavior of a tree frog to test predictions of two hypotheses about the sources of selection acting on signal-timing behavior. We found that female preferences are important in shaping male signal timing, affecting the absolute placement of signals relative to the temporal limits of female preferences. Variation in other signal characters, particularly signal period, also affects signal timing, albeit in a more complicated pattern: the influence of signal period on signal timing varied between populations. Overall, our findings indicate that the evolution of male signal-timing behavior is strongly influenced by female preferences and by an interaction with other aspects of male signaling behavior such as male signal period.