International Res Fellowship Prg: Polymorphism in an Elec Communication Channel:Investigations of Assortative Mating, Heritability, and Environmental Effects on Signal Development

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0502341ArnegardThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Matthew E. Arnegard to work with Dr. Dolph Schluter at the University of British Columbia in Vancouver, Canada.Discrete variation in a communication channel can serve as a model in which to study evolutionary mechanisms underlying diversification in animal communication. When polymorphic signals in a focal organism are used for mate recognition in closely related species, an early stage of speciation or a polymorphic stage preceding it is suggested for the focal taxon. Such a system may exist within the Brienomyrus species flock of electric fishes from Central Africa. Some two dozen 'good' Brienomyrus species are known, each of which exhibits a stereotyped electric organ discharge (EOD). Nested within this group is the magnostipes complex consisting of pairs of morphs which are indistinguishable in appearance but emit distinct EODs. The TYPE I morph of this complex co-occurs with either TYPE II or TYPE III depending on locality. One of the goals of this project is to test whether TYPE I and TYPE II mate assortatively in laboratory streams. In parallel with this study, the PI will indirectly test for assortative mating by artificially creating hybrids and examining whether their EODs differ from TYPEs I and II. He will also estimate the fitness of hybrids relative to offspring derived from crosses within each signal type, and will experimentally test environmental effects on EOD development and expression. Finally, he will exploit the territorial nature of these fish to study behavioral thresholds of EOD discrimination using playback experiments. The outcomes of this study will make important steps toward better understanding of the influences responsible for electric signal diversification in this system.Dolph Schluter's laboratory is the ideal place to pursue these studies. Dr. Schluter has extensively studied assortative mating, phenotypic inheritance, and mating incompatibilities in stickleback fishes. His aquatic facilities will provide resources suitable for breeding experiments under semi-natural conditions and for rearing electric fish from eggs to adults. First-hand comparison of patterns of mate choice and trait inheritance known for sticklebacks to those found in the magnostipes complex will greatly benefit the interpretation results.