The primary sources of 20-hydroxyecdysone in larvae are the prothoracic gland, ring gland, gut, and fat bodies. These tissues convert dietary cholesterol into the mature forms of the hormone 20-hydroxyecdysone.[2] For the most part these glandular tissues are lost in the adult with exception of the fat body, which is retained as a sheath of lipid tissue surrounding the brain and organs of the abdomen. In the adult female the ovary is a substantial source of 20-hydroxyecdysone production.[3] Adult males are left with, so far as is currently known, one source of 20-hydroxyecdysone which is the fat body tissue. These hormone producing tissues express the ecdysone receptor throughout development, possibility indicating a functional feedback mechanism.