Data from: Speciation is not necessarily easier in species with sexually monomorphic mating signals

Should we have different expectations regarding the likelihood and pace of
speciation by sexual selection when considering species with sexually
monomorphic mating signals? Two conditions that can facilitate rapid
species divergence are Felsenstein's one-allele mechanism and a
genetic architecture that includes a genetic association between signal
and preference loci. In sexually monomorphic species, the former can
manifest in the form of mate choice based on phenotype matching. The
latter can be promoted by selection acting upon genetic loci for divergent
signals and preferences expressed simultaneously in each individual rather
than separately, on signal loci in males and preference loci in females.
Both sexes in the Chrysoperla carnea-group of green lacewings (Insecta,
Neuroptera, Chrysopidae) produce sexually monomorphic species-specific
mating signals. We hybridized the two species C. agilis and C. carnea to
test for evidence of these speciation-facilitating conditions. Hybrid
signals were more complex than the parents and we observed a dominant
influence of C. carnea. We found a dominant influence of C. agilis on
preferences in the form of hybrid discrimination against C. carnea.
Preferences in hybrids followed patterns predicting preference loci that
determine mate choice rather than a one-allele mechanism. The genetic
association between signal and preference we detected in the segregating
hybrid crosses indicate that speciation in these species with sexually
monomorphic mating signals can have occurred rapidly. However, we need
additional evidence to determine whether such genetic associations form
more readily in sexually monomorphic species compared to dimorphic species
and consequently facilitate speciation.