Cuticular hydrocarbon profiles in plump bush crickets vary according to species, sex and mating status

Cuticular hydrocarbons (CHCs) serve critical roles in insect communication and desiccation resistance and are increasingly recognized as valuable taxonomic characters. This study investigates inter- and intraspecific variation in CHC profiles across ten Isophya species representing three distinct species groups (zernovi, rectipennis, and staneki), focusing on how these profiles vary by species identity, sex, and mating status. A total of 829 individuals (411 females, 418 males) were sampled and analyzed via GC-MS to quantify CHC composition. Multivariate analyses revealed strong effects of species and sex, as well as significant species × sex × mating status interactions. In both males and females, species in the zernovi group displayed tightly clustered CHC profiles, whereas members of the rectipennis group exhibited broader within-group dispersion, with I. rectipennis forming a distinct cluster. I. staneki was clearly differentiated from all other taxa. CHCs were categorized into six structural classes, with n-alkanes being the most dominant across all taxa. Linear mixed-effects models confirmed that CHC class composition was significantly affected by sex and mating status, particularly for alkenes and methyl-branched alkanes. Notably, nonvirgin individuals showed greater CHC variability, suggesting reproductive condition influences chemical expression. While the study remains descriptive, these findings highlight the potential utility of CHCs in taxonomic resolution, sexual communication, and ecological adaptation in Isophya. The integrative use of CHC data, in combination with morphological and acoustic traits, provides a promising framework for understanding species boundaries and evolutionary divergence in Orthoptera.