Interference with Fatty Acyl-CoA Reductase Reduces Wax Secretion and Influences the Development of Male Ericerus pela (Hemiptera: Coccoidae) Nymphs¹

Ericerus pela Chavannes (Hemiptera: Coccoidae) is a typical scale insect that can secrete a waxy covering over its body to protect itself from adverse factors. This insect significantly damages glossy privets and ash trees in most regions of China. The fatty acyl-CoA reductase (FAR) gene is a crucial enzyme in the cutin, suberine, and wax biosynthesis pathways in these insects and also in fatty acid metabolism. Herein, a synthesized double-stranded RNA of the FAR gene in E. pela (dsEpFAR) was used to explore the effects of dsEpFAR on the expression of EpFAR and secretion of wax and development of E. pela. The results showed that a high concentration of dsEpFAR could cause mortality of male nymphs. After a male nymph was treated with a low dose of dsEpFAR, the transcription level of EpFAR was significantly downregulated, the expression level of EpFAR protein was reduced, and the quantity of wax was markedly decreased, suggesting that EpFAR is a key gene in the biosynthesis of wax and that dsEpFAR can interfere with the gene EpFAR and disrupt the process of wax secretion. The growth and development of male nymphs were also significantly influenced by dsEpFAR treatment, leading to a significantly decreased weight and earlier nymph-to-pupae transition. The findings enhance the molecular understanding of male E. pela wax secretion and facilitate the development of EpFAR-based interference with wax secretion for the integrated management of male E. pela.