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The sensory bases of species and population mate preferences are well known; in frogs properties of the female auditory system influence such preferences. By contrast, there is little understanding of how sensory characteristics could result in sexual selection within a population. One possible mechanism is that females are more sensitive to male courtship signals that deviate from the population mean. We document this mechanism in the frog Physalaemus pustulosus. Female basilar papilla tuning is biased toward lower-than-average frequencies in the 'chuck' portion of the male's call, explaining female preference for the lower-frequency chucks produced by larger males. The tuning does not differ between P. pustulosus and its close relative P. coloradorum, a species in which males never evolved the ability to produce chucks; thus the female tuning evolved before the chuck and therefore the chuck played no role in the evolution of the preference. This allows us to reject two popular hypotheses for the evolution of this female preference (runaway sexual selection and natural selection) in favour of a third: sexual selection for sensory exploitation.

We investigated patterns of mating call preference and mating call recognition by examining phonotaxis of female túngara frogs, Physalaemus pustulosus, in response to conspecific and heterospecific calls. There are four results: females always prefer conspecific calls; most heterospecific calls do not elicit phonotaxis; some heterospecific calls do elicit phonotaxis and thus are effective mate recognition signals; and females prefer conspecific calls to which a component of a heterospecific call has been added to a normal conspecific call. We use these data to illustrate how concepts of species recognition and sexual selection can be understood in a unitary framework by comparing the distribution of signal traits to female preference functions.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 134.129.120.3 on Tue, 30 Jun 2015 15:24:41 UTC All use subject to JSTOR Terms and Conditions Autumn 1964 ANOLINE LIZARDS OF PUERTO RICO 745 Snow, D. W. 1954. The habitats of Eurasian tits (Parus spp.). Ibis 96: 565-585. Stewart, R. E. 1949. Ecology of a nesting red-shouldered hawk population. Wilson Bull. 61: 26-35. , and J. W. Aldrich. 1951. Removal and repopulation of breeding birds in a spruce-fir forest community. Auk 68: 471-482. Stresemann, E. 1950. Interspecific competition in chats. Ibis-92: 148. Sutton, G. M. 1930. The nesting wrens of Brooke County, West Virginia. Wilson Bull. 42: 10-17. Trousdale, B. 1954. Copulation of Anna hummingbirds. Condor 56: 110. Weeden, J. S., and J. B. Falls. 1959. Differential re-sponses of male ovenbirds to recorded songs of neighboring and more distant individuals. Auk 76: 343-351. Wells, P. V. 1958. Indigo buntings in lazuli bunting habitat in southwestern Utah. Auk 75: 223-224. Willson, M. F., and G. H. Orians. 1963. Comparative ecology of red-winged and yellow-headed blackbirds during the breeding season. Proc. XVI Int.Abstract. The eight species of lizards of the genus Anolis in Puerto Rico can be divided into four morphological groups on the basis of general morphological similarities. One, Anolis cviieri, is very different from the rest and has not been discussed here. The other seven species fall into three groups. Each of these three groups occupies a different structural habitat which can be defined in terms of perch height and perch diameter. Within each of these three groups the species have very similar but not identical structural habitats but differ very widely in climatic habitat defined in terms of shade. Shade preferences seem to result from the temperature preferences of the species involved. In each group there is one species with high shade preference which is essentially restricted to the mountains. Each group also has a species with a lower shade preference which occurs in the lowlands and extends up into the mountains in exposed or sunny situations. One of the three groups has an additional species which is restricted to the hot arid southwest corner of Puerto Rico.When one compares the temperature preferences or eccritic temperatures of the various species, one finds in each group that the highland species has a lower eccritic temperature than does the lowland species. There is little temperature difference between the lowland species and arid southwest species in the group where this additional third species is present.The species within each structural habitat show many morphological similarities which may be the result of their being closely related or may be the result of adaptation t...

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