Chorus Size and Call Intensity: Female Choice in the Painted Reed Frog, Hyperolius Marmoratus

Abstract

1. In two-choice phonotaxis experiments female painted reed frogs (Hyperolius marmoratus) preferentially chose the stimulus with the greater sound pressure level (SPL) at source when all other call parameters were identical. 2. However, this preference was not apparent when we increased the distance of the louder stimulus from the female such that the SPL of the two stimuli at the release point was equivalent. This suggests that females simply move up sound gradients ('passive attraction'). 3. Female choice of the loudest stimulus was also affected by the number of speakers. 4. There were significantly fewer responses to the loudest speaker in some four-choice compared to matched two-choice phonotaxis experiments. 5. Together these experimental results may partially account for the absence of a large male mating advantage in the field.