Geographic variation is an important part of the process of speciation and variation in acoustic signals may play a role in reproductive isolation of populations and/or species. Although geographic variation in acoustic signals has been documented in many vertebrate species, it has not been well-documented in teleost fishes. Longear sunfish Lepomis megalotis (Centrarchidae) spawn on the substrate in clear, shallow, flowing water and the young are cared for by the father. Parental male longear sunfish use acoustic signals during the reproductive season, both for intra- and intersexual communication. Females may also use an acoustic signal during courtship. Sunfish calls were recorded using a hydrophone in streams around Austin, Texas. Calls were then digitized and analyzed with wavelet transforms. Playback experiments were conducted using an underwater speaker and digitized calls from multiple creeks. Fish appear to respond preferentially to signals from their own stream. These preliminary results are part of an ongoing investigation of the acoustic environment and its role in signal design of calls in longear sunfish.
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