Integrated transcriptomic and metabolomic analyses reveal information on the sex pheromone biosynthesis pathways of female Anoplophora glabripennis (Coleoptera: Cerambycidae).

Cuticular hydrocarbons (CHCs) are important as protective barriers on insect body surfaces and for chemical signaling, which plays an important role in courtship and mating in Coleoptera. Anoplophora glabripennis, a major pest of healthy broadleaf tree species, infests pathways within tree trunks, causing great economic losses. Contact pheromones of A. glabripennis females, including CHCs, are key substances involved in hermaphrodite recognition and mating. This study compared the CHCs in the cuticles of male and female adult A. glabripennis at different developmental stages, and identified key candidate genes and metabolites affecting courtship and mating behaviors, using a combination of transcriptome sequencing and metabolomics. The CHCs in the cuticles of male and female adults at different developmental stages showed that cuticle long-chain CHC (C ≥ 16) content was much higher than short-chain CHC content (4 < C < 16). Triacontane (C30H62, CAS 638-68-6), a key component of CHCs, was significantly higher in adult females than in adult males during newly emerged and sexually mature stages, but thereafter, its level gradually converged in both sexes with the onset of mating. Combined transcriptomic and metabolomic analyses revealed that lipids and lipid-like metabolites were highly prevalent in both males and females at different developmental stages. Among them, hexadecanoic acid, a fatty acid analog, is a key precursor in contact pheromone biosynthesis in A. glabripennis, and fatty acid synthase (FAS), a key enzyme in the biosynthesis of hexadecanoic acid, could be a potential target for interfering with mating in A. glabripennis.