20-Hydroxyecdysone promotes fat body lipolysis through autophagy during pupation in Apis mellifera

20-hydroxyecdysone (20E) plays a crucial role in insect metamorphosis and has been reported to be involved in fat body lipolysis during pupation in many insects, although this has not been reported in honeybees. Here, we investigated how 20E regulates lipid metabolism during pupation in Apis mellifera. We found that 20E promotes fat body lipolysis by inducing autophagy. 20E treatment reduced fat body triglyceride (TG) content, upregulated lipase-1 and adipokinetic hormone receptor (akhr) expression, and promoted fat body lipolysis. Our lipidomic results showed that honeybee larvae treated with 20E showed significant changes in their TG and phosphatidylcholine (PC) fatty acid levels. In conclusion, we conclude that 20E promotes pupal development by coordinating autophagy and lipid mobilization. This work reveals a novel regulatory mechanism of insect metamorphosis in honeybees and expands our understanding of steroid hormone action in holometabolous insects.