Evidence for no sexual isolation between Drosophila albomicans and D. nasuta

• Authors: Yong-Kyu Kim, Emory University; Dennis R. Phillips, University of Georgia; Yung Tao, Emory University
• Journal Title: Ecology and Evolution
• Volume: Volume 3, Number 7
• Publisher: John Wiley & Sons Ltd. | 2013-07-01, Pages 2061-2074
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1002/ece3.619
• Subjects: Biology, Ecology; Psychology, Developmental; Environmental Sciences; Chemistry, Biochemistry
• Keywords: Science & Technology; Life Sciences & Biomedicine; Ecology; Evolutionary Biology; Environmental Sciences & Ecology; Courtship; cuticular hydrocarbons; D. albomicans; D. nasuta; mating behavior; speciation; Incipient reproductive isolation; Subsequent adult behavior; Cuticular hydrocarbons; Developmental isolation; Premating isolation; Mating preference; Mate recognition; Melanogaster; Speciation; Chromosome

Abstract

Sexual isolation, the reduced tendency to mate, is one of the reproductive barriers that prevent gene flow between different species. Various species-specific signals during courtship contribute to sexual isolation between species. Drosophila albomicans and D. nasuta are closely related species of the nasuta subgroup within the Drosophila immigrans group and are distributed in allopatry. We analyzed mating behavior and courtship as well as cuticular hydrocarbon profiles within and between species. Here, we report that these two species randomly mated with each other. We did not observe any sexual isolation between species or between strains within species by multiple-choice tests. Significant difference in the courtship index was detected between these two species, but males and females of both species showed no discrimination against heterospecific partners. Significant quantitative variations in cuticular hydrocarbons between these two species were also found, but the cuticular hydrocarbons appear to play a negligible role in both courtship and sexual isolation between these two species. In contrast to the evident postzygotic isolation, the lack of sexual isolation between these two species suggests that the evolution of premating isolation may lag behind that of the intergenomic incompatibility, which might be driven by intragenomic conflicts. © 2013 The Authors. Ecology and Evolution.