Data from: Reproductive interference hampers species coexistence despite conspecific sperm precedence

Negative interspecific mating interactions, known as reproductive
interference, can hamper species coexistence in a local patch and promote
niche partitioning or geographical segregation of closely related species.
Conspecific sperm precedence (CSP), which occurs when females that have
mated with both conspecific and heterospecific males preferentially use
conspecific sperm for fertilization, might contribute to species
coexistence by mitigating the costs of interspecific mating and
hybridization. We discussed whether two species exhibiting CSP can coexist
in a local environment in the presence of reproductive interference.
First, using a behaviourally explicit mathematical model, we demonstrated
that two species characterized by negative mating interactions are
unlikely to coexist because the costs of reproductive interference, such
as loss of mating opportunity with conspecific partners, are inevitably
incurred when individuals of both species are present. Second, we
experimentally examined differences in mating activity and preference in
two Harmonia ladybird species known to exhibit CSP.
According to the developed mathematical model of reproductive
interference, these behavioural differences should lead to local
extinction of H. yedoensis because of reproductive
interference by H. axyridis. This prediction is consistent with
field observations that H. axyridis uses various food
sources and habitats whereas H. yedoensis is confined to
a less preferred prey item and a pine tree habitat. Finally, by a
comparative approach, we showed that niche partitioning or parapatric
distribution, but not sympatric coexistence in the same habitat, is
maintained between species with CSP belonging to a wide range of taxa,
including vertebrates and invertebrates living in aquatic or terrestrial
environments. Taken together, we suggest that reproductive interference
can destabilize local coexistence even in closely related species that
exhibit CSP.