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Capa peptides are of great importance for both understanding the control of salt balance by neuropeptides and revealing the mechanisms of response to cold stress. Presently, research on the physiological function of neuropeptides typically includes identifying and analysing specific receptors and their interactions. Given their role in osmotic balance and the importance of cold tolerance, this study attempted to identify the sequence and function of Capa peptide receptors (CapaRs) in Dendroctonus armandi and to prove that CapaRs play an important role in the cold stress responses. In this study, two full‐length cDNAs encoding more than 400 amino acids of Dendroctonus armandi Capa peptide receptor genes (DaCapaRs) and their sequence features were identified using bioinformatic analysis methods. The alignment of DaCapaRs with homologous proteins from other species indicated that the most similar are Dendroctonus ponderosae Capa peptide receptors. The expression of DaCapaRs was high in December and in the larvae, adults and head and midgut of Dendroctonus armandi. In addition, with decreasing temperatures and long‐term exposure to cold conditions, the expression of DaCapaRs increased markedly when the temperature was 4 to –10°C. RNA interference analysis demonstrated that DaCapaRs play an important role in the cold tolerance of overwintering larvae and indicated that a reverse interaction occurs between DaCapaRs and aquaporins. The results showed that DaCapaRs play an essential role in understanding the neuropeptide regulation of cold tolerance in overwintering Dendroctonus armandi larvae and that it can assist in understanding adaptive evolution of Dendroctonus armandi and its relationship with the ecological environment of the Qinling Mountains. [ABSTRACT FROM AUTHOR]

The ability to survive annual temperature minima could be a key determinant of distribution limits for insects under global climate change. Recent studies have suggested that insect aquaporins are indispensable for cellular water management under conditions that lead to dehydration and cold stress. Aquaporins are integral membrane water channel proteins in the major intrinsic protein superfamily and promote selected solutes and the movement of water across biological membranes. We cloned and characterized nine full-length aquaporins from Dendroctonus armandi (DaAqps), the most destructive forest pest in the Qinling Mountains of Shaanxi Province, China. Eight of the DaAqps belong to three classical aquaporin grades, including the Drosophila integral protein, the Pyrocoelia rufa integral protein, the entomoglyceroporins and one that belongs to the unorthodox grade of aquaporin 12-like channels. The DaAqps were increasingly expressed during different developmental stages and in different larval tissues, and expression peaked in mid-winter. They were tested under cold conditions for different lengths of time, and the expression of almost all DaAqps was down regulated with decreasing temperatures and long-term exposure to cold conditions. However, when the lowest temperatures were reached, the levels were immediately upregulated. These genes indicate that cold tolerance can improve through mortality responses at low temperatures after RNA interference of DaAqps. In our study, we analyzed the molecular response, expression patterns, and RNA interference of DaAqps and clarified the crucial role of protective compounds (aquaporins) underlying D. armandi cold tolerance and provide a new pest control method. [ABSTRACT FROM AUTHOR]