The insect fat body is a dynamic tissue involved in energy storage and metabolism, playing a central role in nutrient storage and utilization. It stores energy as glycogen and triglycerides in adipocytes, which are essential for growth, reproduction, and energy during nonfeeding periods. The fat body synthesizes hemolymph proteins, lipophorins, and vitellogenins, and is involved in metabolic processes such as lipid and carbohydrate metabolism, protein synthesis, and amino acid and nitrogen metabolism. It also functions as an endocrine organ, producing antimicrobial peptides and participating in nitrogen metabolism detoxification. The fat body integrates signals from other organs and is hormonally regulated, responding to the metabolic needs of the insect. Nutrient sensing is primarily the domain of the fat body, which expresses amino acid transporters that function as nutrient sensors. The level of nutrient reserves in the fat body influences insect growth, metamorphosis, and egg development. The fat body coordinates insect growth with metamorphosis or reproduction by storing or releasing components central to these events. The fat body is structurally heterogeneous, with different cell types such as adipocytes, urocytes, and mycetocytes, each with specific functions. Adipocytes store lipids, urocytes store urate, and mycetocytes host symbiotic microorganisms. The fat body is a multifunctional organ, involved in energy storage, metabolism, and endocrine functions. It is distributed throughout the insect body, with a loose tissue structure that allows close contact with hemolymph, facilitating energy precursor adjustments. The fat body stores energy as glycogen and triglycerides, which are essential for survival during periods of starvation and metamorphosis. Glycogen is synthesized from UDP-glucose and can be converted to trehalose, while triglycerides are synthesized from dietary carbohydrates, fatty acids, or proteins. Lipid metabolism in the fat body is similar to that in mammalian tissues, with triglycerides being the main storage form. The fat body is involved in the mobilization of energy reserves, including glycogen and triglycerides, to support flight, reproduction, and other physiological processes. Lipases such as TGL and Brummer lipase are involved in triglyceride hydrolysis, while the PAT family proteins Lsd1 and Lsd2 regulate lipid droplet dynamics. AKH (adipokinetic hormone) is a key hormone that stimulates lipolysis and glycogenolysis in the fat body, with its effects mediated through phosphorylation of Lsd1 and activation of TGL. The fat body also plays a role in immune responses, embryogenesis, and lipid mobilization during starvation. Lipids are mobilized to the hemolymph in response to immune challenges and are used as energy sources or for membrane biogenesis. The fat body is essential for the development of oocytes, providing lipids that are transported to the ovaries via lipophorinThe insect fat body is a dynamic tissue involved in energy storage and metabolism, playing a central role in nutrient storage and utilization. It stores energy as glycogen and triglycerides in adipocytes, which are essential for growth, reproduction, and energy during nonfeeding periods. The fat body synthesizes hemolymph proteins, lipophorins, and vitellogenins, and is involved in metabolic processes such as lipid and carbohydrate metabolism, protein synthesis, and amino acid and nitrogen metabolism. It also functions as an endocrine organ, producing antimicrobial peptides and participating in nitrogen metabolism detoxification. The fat body integrates signals from other organs and is hormonally regulated, responding to the metabolic needs of the insect. Nutrient sensing is primarily the domain of the fat body, which expresses amino acid transporters that function as nutrient sensors. The level of nutrient reserves in the fat body influences insect growth, metamorphosis, and egg development. The fat body coordinates insect growth with metamorphosis or reproduction by storing or releasing components central to these events. The fat body is structurally heterogeneous, with different cell types such as adipocytes, urocytes, and mycetocytes, each with specific functions. Adipocytes store lipids, urocytes store urate, and mycetocytes host symbiotic microorganisms. The fat body is a multifunctional organ, involved in energy storage, metabolism, and endocrine functions. It is distributed throughout the insect body, with a loose tissue structure that allows close contact with hemolymph, facilitating energy precursor adjustments. The fat body stores energy as glycogen and triglycerides, which are essential for survival during periods of starvation and metamorphosis. Glycogen is synthesized from UDP-glucose and can be converted to trehalose, while triglycerides are synthesized from dietary carbohydrates, fatty acids, or proteins. Lipid metabolism in the fat body is similar to that in mammalian tissues, with triglycerides being the main storage form. The fat body is involved in the mobilization of energy reserves, including glycogen and triglycerides, to support flight, reproduction, and other physiological processes. Lipases such as TGL and Brummer lipase are involved in triglyceride hydrolysis, while the PAT family proteins Lsd1 and Lsd2 regulate lipid droplet dynamics. AKH (adipokinetic hormone) is a key hormone that stimulates lipolysis and glycogenolysis in the fat body, with its effects mediated through phosphorylation of Lsd1 and activation of TGL. The fat body also plays a role in immune responses, embryogenesis, and lipid mobilization during starvation. Lipids are mobilized to the hemolymph in response to immune challenges and are used as energy sources or for membrane biogenesis. The fat body is essential for the development of oocytes, providing lipids that are transported to the ovaries via lipophorin