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Macroevolutionary consequences of sexual conflict.

Jo S Hermansen1, Jostein Starrfelt2, Kjetil L Voje2

  • 1Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway j.s.hermansen@ibv.uio.no.

Biology Letters
|June 8, 2018
PubMed
Summary

Sexual conflicts over traits shared by both sexes are common. In stalk-eyed flies, strong sexual selection on males did not fully decouple male and female trait evolution over 25 million years.

Keywords:
constraintsmacroevolutionphylogenetic comparative methodssexual conflicttrait integration

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Area of Science:

  • Evolutionary Biology
  • Sexual Selection
  • Macroevolutionary Dynamics

Background:

  • Intralocus sexual conflicts occur when differing fitness optima for a shared trait between sexes are constrained by genetics.
  • These conflicts are frequent, but their long-term evolutionary impact is not well understood.
  • Understanding trait integration is key to exploring sexual conflict consequences.

Purpose of the Study:

  • To investigate the macroevolutionary dynamics of intersexual trait integration in stalk-eyed flies (Diopsidae).
  • To examine the long-term evolutionary consequences of intralocus sexual conflicts.
  • To assess the relationship between sexual selection intensity and trait integration over millions of years.

Main Methods:

  • Employed a Bayesian phylogenetic comparative framework.
  • Analyzed evolutionary patterns in stalk-eyed flies over a 25 million-year timescale.
  • Quantified intersexual trait integration and sex-specific rates of evolution.

Main Results:

  • Increased sexual selection on male eyestalks correlated with reduced intersexual trait integration.
  • Observed sex-specific rates of eyestalk evolution.
  • Despite strong sexual selection, lineages maintained high intersexual trait integration over millions of years.

Conclusions:

  • High trait integration suggests exaggerated female traits may be adaptive or constrained.
  • Sexual conflicts might not always lead to trait decoupling between sexes on macroevolutionary scales.
  • Further research is needed to differentiate the roles of constraints versus selection in trait integration.