Cuticular Hydrocarbon Profiling of Australian Gonipterini Weevils

Cuticular hydrocarbon (CHC) profiling shows promise as a chemotaxonomic tool for identifying and discriminating between closely related insect species. However, there have been limited studies using CHC profiling to differentiate between weevil species (Coleoptera: Curculionidae). This proof-of-concept study investigated the use of CHC and volatile profiling to discriminate between five weevil species from three genera in the Gonipterini tribe. A total of 56 CHCs and 41 other volatile compounds were found across the five species, with 83 of the compounds being identified through their mass fragmentation patterns. The number of CHCs from each species ranged from 20 to 43, while the proportion of CHCs unique to each species varied between 0% and 19%. The most abundant CHCs were nonacosane, 7-methylheptacosane, heptacosane, and hexacosane. Principal component analysis of the centred log-ratio transformed data revealed broad differences in CHC profiles between the two Oxyops species, with Bryachus squamicollis demonstrating the greatest divergence from the other Gonipterini species. The results suggest that CHC analysis could be used to support established taxonomic methods, including morphological features and genetic sequencing results.