title: Cuticular hydrocarbons of Drosophila montana: geographic variation, sexual dimorphism and potential roles as pheromones.
abstract: Sexual selection within populations can play an important role in speciation when divergence in mating signals and their corresponding preferences occur along different coevolutionary trajectories in different populations. In insects, one potential target of sexual selection is the blend of cuticular hydrocarbons (CHCs), which often show intra- and interspecific variation, sexual dimorphism and may act as pheromones. In Drosophila montana, a cold-adapted, circumboreal member of the Drosophila virilis species group, flies from different populations have been found to show significant premating isolation as well as variation in male mating signal (song) and female preference. While the role of male courtship song in mate choice has been studied extensively, CHCs in this species have received little attention. In this study, we identified most of the CHCs found on the cuticle of D. montana and characterized population divergence and sexual dimorphism of CHC profiles among flies established from three natural populations - one European and two North American. We also studied their potential role as pheromones by analyzing CHCs of flies used in female-choice mating experiments. We report significant population×sex effects on CHC profiles, as well as significant relationships between some CHC principal components and particular mating behaviours, such as female attractiveness and male mating success, providing evidence that CHCs may play a role in mate choice in this species. The study also provides evidence for variation in the degree to which CHCs play a role in chemical communication among these populations, which may have an influence on the speciation process itself, and could be due to variation in interactions with other closely-related species that occur sympatrically with D. montana in some, but not other, parts of its distribution.
authors.affiliation: Program in Ecology and Evolutionary Biology, Department of Biological Sciences, University of Arkansas, AR 72701, USA; Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä 40014, Finland. Electronic address: jjenning@uark.edu.
authors.forename: Jackson H
authors.initials: JH
authors.lastname: Jennings
authors.affiliation: Program in Ecology and Evolutionary Biology, Department of Biological Sciences, University of Arkansas, AR 72701, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Etges
authors.affiliation: Department of Animal Ecology and Tropical Biology, Faculty of Biology, University of Würzburg, Würzburg 97074, Germany; Ecological Networks, Faculty of Biology, Technical University of Darmstadt, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitt
authors.affiliation: Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä 40014, Finland.
authors.forename: Anneli
authors.initials: A
authors.lastname: Hoikkala
mesh_terms: D000819:Animal Communication; D000818:Animals; D001955:British Columbia; D003120:Colorado; D004330:Drosophila / Q000737:chemistry* / Q000502:physiology*; D004817:Epidermis / Q000378:metabolism; D005260:Female; D005387:Finland; D008401:Gas Chromatography-Mass Spectrometry; D006838:Hydrocarbons / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D052586:Mating Preference, Animal; D010675:Pheromones / Q000378:metabolism*; D012724:Sex Attractants / Q000378:metabolism
chemical_list: D006838:Hydrocarbons; D010675:Pheromones; D012724:Sex Attractants; C010411:insect attractants
keywords: CHCs; Mate choice; Pheromones; Sexual selection; Speciation