Abstract: 【Aim】Adipokinetic hormone (AKH), a type of neuropeptide, plays central roles in regulating development and behavioral events in diverse insects. Investigating the functions of AKH on the growth and development of Bactrocera dorsalis larva will contribute to a better understanding of the conservation and functional diversity of neuropeptides in insects, and may shed light on evaluating the potential of AKH signal system as the target of novel insect control agents. 【Methods】The full-length cDNA sequence of BdAKH of B. dorsalis was cloned, and characterized with bioinformatics methods. The expression levels of BdAKH in different developmental stages (egg, 1st-3rd instar larvae, pupa, virgin female adult and male adult), and different tissues ［central nervous system, corpora cardiaca/corpus allatum (CC/CA), fat body, Malpighian tubules, midgut, hindgut, cuticle, ovary, testis and hemocytes］ of the late 3th instar larva of B. dorsalis were detected by qPCR. Immunohistochemistry technique was used to localize the neurons expressing BdAKH in the 3rd instar larva of B. dorsalis. RNAi combined with biological observation was used to analyze the regulation of BdAKH on the growth and development of B. dorsalis larva.【Results】The full-length cDNA sequence of BdAKH (GenBank accession no. KY073319) of B. dorsalis was cloned. This cDNA of 572 bp contains an open reading frame (ORF) of 252 bp, which encodes 83 amino acid residues. BdAKH of B. dorsalis has conserved structure that consists of one mature peptide (QLTFSPDWamide). The expression levels of BdAKH were higher in adult. BdAKH was mainly expressed in the CC/CA of the late 3rd instar larva. Compared with the control group (dsGFP), BdAKH knockdown in the 3rd instar larva of B. dorsalis caused a delay in pupation and decreased pupation rate, while the pupal weight and phenotype had no remarkable difference. 【Conclusion】AKH plays important roles in regulating the larval growth and development of B. dorsalis, which could be viewed as new targets of novel insect control agents.

Key words: Bactrocera dorsalis; adipokineic hormone, expression pattern, energy metabolism, growth and development