Simultaneous mate-sampling by female barking treefrogs (Hyla gratiosa)

Mate-sampling behavior describes how individuals gather information about potential mates and incorporate that information into mating decisions. Conclusively identifying the mate-sampling tactic employed by choosing individuals has proved difficult for many species. To determine the sampling tactic used by female barking treefrogs (Hyla gratiosa), I conducted 8-speaker playback experiments in which the speakers were arrayed along an arc that mimicked the natural spatial distribution of males confronting choosing females. One speaker broadcast an attractive call, whereas the other 7 broadcast an unattractive call; the speaker broadcasting the attractive call was never the closest to the female’s release point. Females bypassed the closest speakers to choose the more distant, more attractive call when they had to travel an additional 1.4 or 2.8 m to reach the speaker broadcasting the attractive call; they did not prefer the more attractive call if they had to travel an additional 5.8 m. To determine the number of males sampled by females, I held constant the additional distance required to reach the speaker broadcasting the more attractive call while at the same time varying the total number of speakers located within that distance of the release point. The results of these experiments showed that all females sampled at least 4 speakers and that some sampled as many as 8. These results establish experimentally that female H. gratiosa sample males simultaneously from a distance and that they trade off call characteristics and distance to potential mates when choosing mates.