title: Phylogeny of diving beetles reveals a coevolutionary arms race between the sexes.
abstract: BACKGROUND
  Darwin illustrated his sexual selection theory with male and female morphology of diving beetles, but maintained a cooperative view of their interaction. Present theory suggests that instead sexual conflict should be a widespread evolutionary force driving both intersexual coevolutionary arms races and speciation.
  
  
  RESULTS
  We combined Bayesian phylogenetics, complete taxon sampling and a multi-gene approach to test the arms race scenario on a robust diving beetle phylogeny. As predicted, suction cups in males and modified dorsal surfaces in females showed a pronounced coevolutionary pattern. The female dorsal modifications impair the attachment ability of male suction cups, but each antagonistic novelty in females corresponds to counter-differentiation of suction cups in males.
  
  
  CONCLUSIONS
  A recently diverged sibling species pair in Japan is possibly one consequence of this arms race and we suggest that future studies on hypoxia might reveal the key to the extraordinary selection for female counter-adaptations in diving beetles.
authors.affiliation: Entomology Department, Natural History Museum, London, United Kingdom; Division of Biology, Imperial College London, Silwood Park Campus, Ascot, United Kingdom. j.bergsten@nhm.ac.uk
authors.forename: Johannes
authors.initials: J
authors.lastname: Bergsten
authors.forename: Kelly B
authors.initials: KB
authors.lastname: Miller
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D001517:Coleoptera / Q000502:physiology*; D003163:Competitive Behavior; D005260:Female; D008297:Male; D010802:Phylogeny; D012726:Sexual Behavior, Animal