Data from: Rapid evolution of asymmetric reproductive incompatibilities in stalk-eyed flies

The steps by which isolated populations acquire reproductive
incompatibilities remain poorly understood. One potentially important
process is postcopulatory sexual selection because it can generate
divergence between populations in traits that influence fertilization
success after copulation. Here we present a comprehensive analysis of this
form of reproductive isolation by conducting reciprocal crosses between
variably diverged populations of stalk-eyed flies (Teleopsis dalmanni).
First, we measure seven types of reproductive incompatibility between
copulation and fertilization. We then compare fertilization success to
hatching success to quantify hybrid inviability. Finally, we determine if
sperm competition acts to reinforce or counteract any incompatibilities.
We find evidence for multiple incompatibilities in most crosses, including
failure to store sperm after mating, failure of sperm to reach the site of
fertilization, failure of sperm to fertilize eggs, and failure of embryos
to develop. Local sperm have precedence over foreign sperm, but this
effect is due mainly to differences in sperm transfer and reduced hatching
success. Crosses between recently diverged populations are asymmetrical
with regard to the degree and type of incompatibility. Because sexual
conflict in these flies is low, postcopulatory sexual selection, rather
than antagonistic coevolution, likely causes incompatibilities due to
mismatches between male and female reproductive traits.