Sexual selection and the detection of ecological speciation

Context: Ecological speciation is commonly inferred with evidence of the parallel evolution of pre-mating isolation: individuals from populations in similar environments show higher mating success in laboratory experiments than do individuals from different environments. Critically, this should hold even for mating crosses among populations that are from different locations that represent independent evolutionary lineages. Problem: This prediction may not hold when conserved sexual selection (e.g. good genes benefits) constrains the evolution of mate preferences. In this case, ecological pre-mating isolation may be developing but is difficult to infer using the typical experimental approach. Solution: We show how comparisons of mate preference functions among replicate populations in divergent environments can be used to reveal subtle signatures of ecological speciation. These functions can then be used to develop predictions of relative mating success in population crosses. Significance: This general approach, based on mate preference functions, facilitates the simultaneous analysis of both pattern and process during ecological speciation.