Evol Ecol Res 1: 567-579 (1999)     Full PDF if your library subscribes.

Short-term evolution of competition between genetically homogeneous and heterogeneous populations of Drosophila melanogaster

Mercedes Becerra, Isabel Brichette and Carlos Garcia*

Area de Xenetica, Facultade de Bioloxía, Universidade de Santiago, 15706 Santiago de Compostela, A Coruña, Galicia, Spain

Author to whom all correspondence should be addressed.
e-mail: bfcarlog@uscmail.usc.es

ABSTRACT

Sexual reproduction may confer an advantage in intraspecific competition. We tested this by studying the evolution of larval competition between two populations of the fruit fly Drosophila melanogaster, one of them having genetic variability and the other being highly homogeneous, like an asexual strain would be. We found a clear response in competitive ability in the heterogeneous populations competing with three of the four genotypes assayed as homogeneous populations. In only six generations was this response enough to cancel out the double advantage in reproductive rate that would be expected in an asexually reproducing female. However, the outcome of the competition was genotype-dependent, as the fourth homogeneous genotype developed a competitive advantage through the generations. Thus, selection for larval competitive ability could play an important role in the maintenance of sexual reproduction in Drosophila, but would not be enough to ensure it, as some genotypes could overcome its effect if switching to asexual reproduction.

Keywords: co-existence, evolution of sex, genetic homogeneity, intraspecific competition.

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        © 1999 Carlos Garcia. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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