International Journal of Evolutionary Biology Mechanisms of Speciation Guest Editors: Kyoichi Sawamura, Chau-Ti Ting, Artyom Kopp, and Leonie C. Moyle Mechanisms of Speciation International Journal of Evolutionary Biology Mechanisms of Speciation Guest Editors: Kyoichi Sawamura, Chau-Ti Ting, Artyom Kopp, and Leonie C. Moyle Copyright © 2012 Hindawi Publishing Corporation. All rights reserved. This is a special issue published in “International Journal of Evolutionary Biology.” All articles are open access articles distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Editorial Board Giacomo Bernardi, USA Kazuho Ikeo, Japan Jeffrey R. Powell, USA Terr y Burke, UK Yoh Iwasa, Japan Hudson Kern Reeve, USA Ignacio Doadrio, Spain Henrik J. Jensen, UK Y. Satta, Japan Simon Easteal, Australia Amitabh Joshi, India Koji Tamura, Japan Santiago F. Elena, Spain Hirohisa Kishino, Japan Yoshio Tateno, Japan Renato Fani, Italy A. Moya, Spain E. N. Trifonov, Israel Dmitry A. Filatov, UK G. Pesole, Italy Eske Willerslev, Denmark F. Gonza’lez-Candelas, Spain I. Popescu, USA Shozo Yokoyama, USA D. Graur, USA David Posada, Spain Contents Mechanisms of Speciation, Kyoichi Sawamura, Chau-Ti Ting, Artyom Kopp, and Leonie C. Moyle Volume 2012, Article ID 820358, 2 pages Cuticular Hydrocarbon Content that Affects Male Mate Preference of Drosophila melanogaster from West Africa, Aya Takahashi, Nao Fujiwara-Tsujii, Ryohei Yamaoka, Masanobu Itoh, Mamiko Ozaki, and Toshiyuki Takano-Shimizu Volume 2012, Article ID 278903, 10 pages Evolutionary Implications of Mechanistic Models of TE-Mediated Hybrid Incompatibility, Dean M. Castillo and Leonie C. Moyle Volume 2012, Article ID 698198, 12 pages DNA Barcoding and Molecular Phylogeny of Drosophila lini and Its Sibling Species, Yi-Feng Li, Shuo-Yang Wen, Kuniko Kawai, Jian-Jun Gao, Yao-Guang Hu, Ryoko Segawa, and Masanori J. Toda Volume 2012, Article ID 329434, 9 pages Postzygotic Isolation Evolves before Prezygotic Isolation between Fresh and Saltwater Populations of the Rainwater Killifish, Lucania parva, Genevieve M. Kozak, Arthur B. Rudolph, Beatrice L. Colon, and Rebecca C. Fuller Volume 2012, Article ID 523967, 11 pages Divergent Evolution of Male Aggressive Behaviour: Another Reproductive Isolation Barrier in Extremophile Poeciliid Fishes?, David Bierbach, Moritz Klein, Vanessa Sassmannshausen, Ingo Schlupp, Rudiger¨ Riesch, Jakob Parzefall, and Martin Plath Volume 2012, Article ID 148745, 14 pages Rapid Evolution of Assortative Fertilization between Recently Allopatric Species of Drosophila, Yasir H. Ahmed-Braimah and Bryant F. McAllister Volume 2012, Article ID 285468, 9 pages A Phenotypic Point of View of the Adaptive Radiation of Crested Newts (Triturus cristatus Superspecies, Caudata, Amphibia),AnaIvanovic,´ Georg Dzukiˇ c,´ and MilosKaleziˇ c´ Volume 2012, Article ID 740605, 9 pages Inter- and Intraspecific Variation in Drosophila Genes with Sex-Biased Expression,LenaMuller,¨ Sonja Grath, Korbinian von Heckel, and John Parsch Volume 2012, Article ID 963976, 10 pages Differences in Chemical Sexual Signals May Promote Reproductive Isolation and Cryptic Speciation between Iberian Wall Lizard Populations, Marianne Gabirot, Pilar Lopez,´ and JoseMart´ ´ın Volume 2012, Article ID 698520, 13 pages 170 Years of Lock-and-Key: Genital Morphology and Reproductive Isolation,JohnP.Masly Volume 2012, Article ID 247352, 10 pages Chromatin Evolution and Molecular Drive in Speciation,KyoichiSawamura Volume 2012, Article ID 301894, 9 pages Hindawi Publishing Corporation International Journal of Evolutionary Biology Volume 2012, Article ID 820358, 2 pages doi:10.1155/2012/820358 Editorial Mechanisms of Speciation Kyoichi Sawamura,1 Chau-Ti Ting,2 Artyom Kopp,3 and Leonie C. Moyle4 1 Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan 2 Department of Life Science, National Taiwan University, Taipei 10617, Taiwan 3 Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA 4 Department of Biology, Indiana University, Bloomington, IN 47405, USA Correspondence should be addressed to Kyoichi Sawamura, [email protected] Received 21 February 2012; Accepted 21 February 2012 Copyright © 2012 Kyoichi Sawamura et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. “Speciation” was largely “speculation” two decades ago, at where heterospecific fertilization after mating is compro- least with respect to a detailed and comprehensive mechanis- mised due to disruptions in sperm storage and motility. tic understanding of the origin of new species. Despite Often, reproductive isolation evolves more rapidly than any elegant classical work examining the genetic basis of interspe- morphological traits so that the only way to distinguish cific differences and reproductive isolation and complemen- recently diverged species is through mating experiments. tary studies of the ecological factors that can contribute to Y.-F. Li et al. in “DNA barcoding and molecular phylogeny of species divergence, speciation researchers lacked the tools to Drosophila lini and its sibling species” showed that molecular dissect the specific forces, traits, and genes involved. Thanks variation can also be widely shared between sibling species to the recent advances in molecular biology and genomic despite strong reproductive isolation between them. To sequencing, detailed study of speciation is becoming feasible understand why reproductive isolation can evolve so rapidly in many animal and plant groups. In fact, a dozen of compared to other traits, L. Muller¨ et al. in “Inter- and “speciation genes” responsible for reproductive isolation intraspecific variation in Drosophila genes with sex-biased between sibling species have been identified at the molecular expression” examined the evolution of gene expression and level. Further, genetic changes leading to morphological protein sequences and found that genes with male-biased differentiation among related species have been elucidated, expression tend to diverge rapidly compared to the rest of supported by phylogenetic analyses at high resolution. We the genome. invited investigators to contribute both original research and Three other original articles deal with reproductive isola- review articles that would stimulate the continuing efforts tion in vertebrates, specifically fish or reptiles. D. Bierbach to understand speciation and species differentiation from all et al. in “Divergent evolution of male aggressive behavior: perspectives, not only the genetic mechanisms but also the another reproductive isolation barrier in extremophile poeciliid ecological and evolutionary causes. fishes?” reported a rare case study of behavioral isolation Among the seven original articles in this special issue, via local adaptation to extreme environmental conditions four were Drosophila studies. Two of them focus on the (darkness in caves and toxic hydrogen sulphide). G. M. mechanisms of reproductive isolation. A. Takahashi et al. Kozak et al. in “Postzygotic isolation evolves before prezygotic in “Cuticular hydrocarbon content that affects male mate isolation between fresh and saltwater populations of the rain- preference of Drosophila melanogaster from west Africa” water killifish, Lucania parva” discovered a case of incipient identified a polymorphic chemical cue involved in mate reproductive isolation caused by salinity adaption, in which recognition between sibling species. Y. H. Ahmed-Braimah they found no evidence of prezygotic isolation but detected and B. F. McAllister in “Rapid evolution of assortative reduced hybrid survival. M. Gabirot et al. in “Differences fertilization between recently allopatric species of Drosophila” in chemical sexual signals may promote reproductive isolation described an example of postmating/prezygotic isolation, and cryptic speciation between Iberian wall lizard populations” 2 International Journal of Evolutionary Biology reported another case of cryptic speciation caused by pheromonal differentiation, in which they demonstrated that the Iberian wall lizard forms part of a “species complex” with different morphology and different proportions of chemical components in femoral gland secretions of males. This special issue also includes four review articles. A. Ivanovic´ et al. in “A phenotypic point of view of the adaptive radiation of crested newts (Triturus cristatus super- species, Caudata, Amphibia)” reviewed the pattern of adapt- ive radiation in the European crested newt, in which they suggested that phenotypic diversification was caused by heterochronic changes linked to variation in ecological preferences. J. P.Masly in “170 years of “lock-and-key”: genital morphology and reproductive isolation” reviewed the facts and speculations about the role of genital morphology in maintaining species barriers and examined the prospects for identifying the genetic changes responsible for the evolution of genital morphology. D. M. Castillo and L. C. Moyle in “Evolutionary implications of mechanistic models of TE-mediatedhybridincompatibility” reviewed mechanistic models of host-mediated TE suppression in light of the potential role of TE derepression in postzygotic isolation and identified data that would be necessary to provide more satisfactory