Data from: Divergence in cuticular wax profiles generates partial behavioural isolation between leaf beetle populations with different dispersal traits

Sex pheromones are among the most studied insect mating signals, with
their extensive diversity underscoring their crucial role in promoting
behavioural isolation during speciation. In Chrysomelidae, cuticular wax
(CW), a hydrophobic layer covering the insect cuticle, is a potential
barrier that facilitates behavioural isolation. Male leaf beetles use
female CW as a mating signal, and their species-specific profiles prevent
heterospecific mating between closely related species, implying that
divergence in CW profiles promotes reproductive isolation, and, hence,
contributes to speciation. However, the role of CW as an isolating barrier
remains unclear owing to limited knowledge regarding intraspecific
divergence in female CW and its coevolution with male preferences. Through
chemical analysis and behavioural experiments, we demonstrated that
intraspecific divergence in female CW profiles contributes to partial
behavioural isolation between leaf beetle populations with different
dispersal traits: the flight-capable macropterous and flightless
brachypterous forms of Galerucella grisescens (Coleoptera: Chrysomelidae).
To the best of our knowledge, this is the first study on the coevolution
of female CW and male preferences at the intraspecific level in
Coleoptera. Our results support the potential role of CW as an isolating
barrier in Chrysomelidae and are consistent with previous findings that
loss of flight enhances beetle diversification.