Divergent natural selection drives the evolution of reproductive isolation in an Australian wildflower

Thomas J. Richards, Greg M. Walter, Katrina McGuigan, Daniel Ortiz-Barrientos

Research output: Contribution to journalArticleResearchpeer-review

11 Citations (Scopus)

Abstract

Ecological speciation occurs when reproductive isolation evolves between populations adapting to contrasting environments. A key prediction of this process is that the fitness of hybrids between divergent populations should be reduced in each parental environment as a function of the proportion of local genes they carry, a process resulting in ecologically dependent reproductive isolation (RI). To test this prediction, we use reciprocal transplant experiments between adjacent populations of an Australian wildflower, Senecio lautus, at two locations to distinguish between ecologically dependent and intrinsic genetic reproductive barriers. These barriers can be distinguished by observing the relative fitness of reciprocal backcross hybrids, as they differ in the contribution of genes from either parent while controlling for any intrinsic fitness effects of hybridization. We show ecologically dependent fitness effects in establishment and survival of backcrosses in one transplant experiment, and growth performance in the second transplant experiment. These results suggest natural selection can create strong reproductive barriers that maintain differentiation between populations with the potential to interbreed, and implies a significant role for ecology in the evolutionary divergence of S. lautus.

Original languageEnglish
Pages (from-to)1993-2003
Number of pages11
JournalEvolution
Volume70
Issue number9
DOIs
Publication statusPublished - 1 Sep 2016
Externally publishedYes

Keywords

  • Ecological speciation
  • MCMCglmm
  • postzygotic isolation
  • reciprocal transplant
  • Senecio

Cite this