Data from: Male and female contributions to behavioral isolation in darters as a function of genetic distance and color distance

Determining which reproductive isolating barriers arise first between
geographically isolated lineages is critical to understanding allopatric
speciation. We examined behavioral isolation among four recently diverged
allopatric species in the orangethroat darter clade (Etheostoma: Ceasia).
We also examined behavioral isolation between each Ceasia species and the
sympatric rainbow darter Etheostoma caeruleum. We asked (1) is behavioral
isolation present between allopatric Ceasia species, and how does this
compare to behavioral isolation with E. caeruleum, (2) does male color
distance and/or genetic distance predict behavioral isolation between
species, and (3) what are the relative contributions of female choice,
male choice, and male competition to behavioral isolation? We found that
behavioral isolation, genetic differentiation, and male color pattern
differentiation were present between allopatric Ceasia species. Males, but
not females, discerned between conspecific and heterospecific mates. Males
also directed more aggression towards conspecific rival males. The high
levels of behavioral isolation among Ceasia species showed no obvious
pattern with genetic distance or male color distance. However, when the E.
caeruleum was included in the analysis, an association between male
aggression and male color distance was apparent. We discuss the
possibility that reinforcement between Ceasia and E. caeruleum is driving
behavioral isolation among allopatric Ceasia species.