Pattern recognition and call preferences in treefrogs (Anura: Hylidae): a quantitative analysis using a no-choice paradigm

Studies of mate attraction have traditionally employed one of two experimental methods: choice tests in which female preferences from among two or more signals are tabulated, or single-stimulus tests in which the female response to one signal is quantified. Choice tests have long been preferred for examining mate attraction in anurans. Inspired by Wagner's (1998, Animal Behaviour,55, 1029–1042) discussion of the strengths and weaknesses of the two experimental approaches, we used a single-stimulus design to examine mate attraction in two sibling species of treefrogs (Hyla versicolor and H.chrysoscelis). We quantified female responses based upon the relative time required to approach signals varying in pulse rate, pulse rise time and pulse number. The data were used to generate response functions providing a quantitative measure of female attraction to the stimuli. Comparisons with data from choice experiments reveal broad similarities, as well as properties of female responses that had not been detected with choice tests. The results are discussed with regard to female selectivity for call parameters that are likely to mediate sexual selection and homospecific pairing.