20-Hydroxyecdysone (ecdysterone or 20E)'s a naturally occurring ecdysteroid hormone which controls the ecdysis (moulting) and metamorphosis of arthropods. It's therefore one of the most common moulting hormones in insects, crabs, etc. It's also a phytoecdysteroid produced by various plants, including Cyanotis vaga, where its purpose's presumably to disrupt the development and reproduction of insect pests. In arthropods, 20E acts through the ecdysone receptor. Although mammals lack this receptor… (More on Ecdysterone)