Sexual selection and interacting phenotypes in experimental evolution: a study of Drosophila pseudoobscura mating behavior.
Sexual selection requires social interactions, particularly between the sexes. When trait expression is influenced by social interactions, such traits are called interacting phenotypes and only recently have the evolutionary consequences of interacting phenotypes been considered. Here we investigated how variation in relative fitness, or the opportunity for sexual selection, affected the evolutionary trajectories of interacting phenotypes. We used experimentally evolved populations of the naturally promiscuous Drosophila pseudoobscura, in which the numbers of potential interactions between the sexes, and therefore relative fitness, were manipulated by altering natural levels of female promiscuity. We considered two different mating interactions between the sexes: mating speed and copulation duration. We investigated the evolutionary trajectories of means and (co)variances (P) and also the influence of genetic drift on the evolutionary response of these interactions. Our sexual selection treatments did not affect the means of either mating speed or copulation duration, but they did affect P. We found that the means of both traits differed among replicates within each selection treatment whereas the Ps did not. Changes as a consequence of genetic drift were excluded. Our results show that although variable potential strengths of sexual interactions influence the evolution of interacting phenotypes, the influence may be nonlinear.
Bacigalupe
Leonardo D
LD
Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, United Kingdom.
Crudgington
Helen S
HS
Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, United Kingdom.
Slate
Jon
J
Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, United Kingdom.
Moore
Allen J
AJ
Centre for Ecology and Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, TR10 9EZ, United Kingdom.
Snook
Rhonda R
RR
Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, United Kingdom.| Email: r.snook@sheffield.ac.uk.
D000818:Animals; D005075:Biological Evolution; D004330:Drosophila / Q000235:genetics*; D005260:Female; D040961:Genetic Drift; D008297:Male; D015999:Multivariate Analysis; D010641:Phenotype; D012641:Selection, Genetic; D012726:Sexual Behavior, Animal