Data from: Multiple reproductive barriers separate recently diverged sunflower ecotypes

Measuring reproductive barriers between groups of organisms is an
effective way to determine the traits and mechanisms that impede gene
flow. However, to understand the ecological and evolutionary factors that
drive speciation, it is important to distinguish between the barriers that
arise early in the speciation process and those that arise after
speciation is largely complete. In this paper we comprehensively test for
reproductive isolation between recently diverged (< 10,000 years
bp) dune and non-dune ecotypes of the prairie sunflower, Helianthus
petiolaris. We find reproductive barriers acting at multiple stages of
hybridization, including premating, postmating-prezygotic, and postzygotic
barriers, despite the recent divergence. Barriers include extrinsic
selection against immigrants and hybrids, a shift in pollinator
assemblage, and post-pollination assortative mating. Together these data
suggest that multiple barriers can be important for reducing gene flow in
the earliest stages of speciation.