title: The complex interplay between macronutrient intake, cuticular hydrocarbon expression and mating success in male decorated crickets.
abstract: The condition dependence of male sexual traits plays a central role in sexual selection theory. Relatively little, however, is known about the condition dependence of chemical signals used in mate choice and their subsequent effects on male mating success. Furthermore, few studies have isolated the specific nutrients responsible for condition-dependent variation in male sexual traits. Here, we used nutritional geometry to determine the effect of protein (P) and carbohydrate (C) intake on male cuticular hydrocarbon (CHC) expression and mating success in male decorated crickets (Gryllodes sigillatus). We show that both traits are maximized at a moderate-to-high intake of nutrients in a P:C ratio of 1 : 1.5. We also show that female precopulatory mate choice exerts a complex pattern of linear and quadratic sexual selection on this condition-dependent variation in male CHC expression. Structural equation modelling revealed that although the effect of nutrient intake on mating success is mediated through condition-dependent CHC expression, it is not exclusively so, suggesting that other traits must also play an important role. Collectively, our results suggest that the complex interplay between nutrient intake, CHC expression and mating success plays an important role in the operation of sexual selection in G. sigillatus.
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.
authors.forename: J
authors.initials: J
authors.lastname: Rapkin
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.|Department of Bioscience, Terrestrial Ecology, Aarhus University, Silkeborg, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Jensen
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.|School of Science and Health, and Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia.
authors.forename: C M
authors.initials: CM
authors.lastname: House
authors.affiliation: Behaviour, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Sakaluk
authors.affiliation: Department of Psychology, University of Victoria, Victoria, BC, Canada.
authors.forename: J K
authors.initials: JK
authors.lastname: Sakaluk
authors.affiliation: Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.|School of Science and Health, and Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Hunt
mesh_terms: D000818:Animals; D005260:Female; D006135:Gryllidae / Q000502:physiology*; D006838:Hydrocarbons; D008297:Male; D010641:Phenotype; D012098:Reproduction; D012726:Sexual Behavior, Animal
chemical_list: D006838:Hydrocarbons
keywords: 
  Gryllodes sigillatus
  ; chemical signals; macronutrients; mating success; selection analysis; sexual selection