Data from: Postcopulatory sexual selection generates speciation phenotypes in Drosophila

Background: Identifying traits that reproductively isolate species, and
the selective forces underlying their divergence, is a central goal of
evolutionary biology and speciation research. There is growing recognition
that postcopulatory sexual selection, which can drive rapid
diversification of interacting ejaculate and female reproductive tract
traits that mediate sperm competition, may be an engine of speciation.
Conspecific sperm precedence (CSP) is a taxonomically widespread form of
reproductive isolation, but the selective causes and divergent traits
responsible for CSP are poorly understood. Results: To test the hypothesis
that postcopulatory sexual selection can generate reproductive isolation,
we expressed green (GFP) or red fluorescent protein (RFP) in sperm heads
of recently diverged sister species, Drosophila simulans and D.
mauritiana, to enable detailed resolution of species-specific sperm
precedence mechanisms. Between-species divergence in sperm competition
traits and mechanisms prompted six a priori predictions regarding
mechanisms of CSP and degree of cross asymmetry in reproductive isolation.
We resolved four distinct mechanisms of CSP that were highly consistent
with predictions. These comprise interactions between multiple
sex-specific traits, including two independent mechanisms by which females
exert sophisticated control over sperm fate to favor the conspecific male.
Conclusions: Our results confirm that reproductive isolation can quickly
arise from diversifying (allopatric) postcopulatory sexual selection. This
experimental approach to "speciation phenotypes" illustrates how
knowledge of sperm precedence mechanisms can be used to predict the
mechanisms and extent of reproductive isolation between populations and
species.