Comparative analysis of cuticular hydrocarbon profiles among three dominant tenebrionid species (Coleoptera: Tenebrionidae) from the Turpan Basin

Insects can utilize their cuticular hydrocarbons (CHCs) to reduce water loss caused by transpiration, enabling them to survive and reproduce in arid environments. Moreover, the differences in key CHCs among different species can be used for species identification.

This study investigated the CHCs profiles of three dominant desert tenebrionid beetles (Trigonoscelis holdereri, Sternoplax szechenyi, and Colposcelis montivaga) in the Turpan Basin using gas chromatography-mass spectrometry (GC-MS), aiming to elucidate their adaptation to extreme aridity and taxonomic applications.

Key findings revealed: CHC composition and arid adaptation: A total of 44 CHCs were identified, dominated by n-alkanes (47.93%~53.57%) that primarily consisted of odd-numbered long-chain alkanes (C₂₇, C₂₉, C₃₁) with only four short-chain alkanes (< C₂₀), while T. holdereri uniquely contained ultra-long-chain alkanes (C₃₄-C₄₀) Mono-methyl branched alkanes constituted the major iso-alkane fraction (34.74%~47.06%), while poly-methylated alkanes (1.67%~5.41%) and alkenes (2.57%~6.28%) were minimal. Principal component analysis (PCA) revealed convergent CHC profiles among the three tenebrionids with desert-adapted arthropods (Schistocerca gregaria and Pogonomyrmex barbatus) but divergent from mesophilic tenebrionids, supporting a water conservation strategy through long-chain n-alkane dominance, mono-methyl branching optimization, and poly-methylation suppression. Chemotaxonomic significance: Discriminant analysis based on 11 diagnostic CHC markers (Wilks'λ = 0, P < 0.001) achieved perfect species discrimination. Clustering patterns aligned with a concatenated COI-28S phylogeny (BPP = 1.00), confirming species-specific CHC signatures. Heatmap analysis demonstrated higher intraspecific CHC homogeneity than interspecific variability, validating their role as a complementary tool for morphological taxonomy.

This study delineates xeromorphic CHC adaptation patterns in desert tenebrionids and establishes CHCs as robust biomarkers for sympatric species delimitation, advancing our understanding of insect adaptive evolution in extreme arid environments.