Diversity of cuticular hydrocarbon profiles among Australian Gonipterini (Coleoptera: Curculionidae) genera and species

Cuticular hydrocarbon (CHC) profiling is a promising chemotaxonomic tool for discriminating between related insect species. However, there have been limited studies performed on weevils (Coleoptera: Curculionidae) to date, despite the immense number of species in this family. Consequently, this study investigated the prospect of CHC profiling for discriminating between different genera and species in the economically significant Gonipterini tribe. Consequently, the CHC profiles of fifteen Gonipterini specimens were analysed, comprising five species from three genera: namely Bryachus squamicollis, Gonipterus cinnamomeus, Gonipterus sp. n. 2, Oxyops fasciculatus and an undescribed Oxyops species. A total of 83 compounds were identified across the five Gonipterini species, with an additional 14 compounds present but unable to be precisely identified. The most abundant CHCs were nonacosane, 7-methylheptacosane, heptacosane and hexacosane, while the most abundant CHC classes were methyl alkanes, aldehydes and n-alkanes. The number of compounds found in each species ranged from 35 to 71, with the proportion of compounds unique to each species varying between 3.7% to 28.2%. Principal component analysis and hierarchical cluster analysis revealed Bryachus squamicollis to be the most dissimilar species in terms of its CHC profile, while the two Oxyops species showed relatively similar CHC profiles. Used in combination with established taxonomic methods, CHC profiling could be used to support taxonomic identifications and descriptions of new species.