In larval form, the Monarch feeds on milkweed[?], and sequesters substances called cardenolides[?], related to the cardiac glycoside digitalis: the amount accumulated depends on the level present in the milkweed. This accumulation makes the adult butterfly distasteful and poisonous to Blue Jays and other would-be predators, and many such animals avoid consuming it: this has resulted in the evolution of mimics, which are colored like the monarch to ward off animals but are not themselves poisonous.
The species was described by Carolus Linnaeus in 1758.
wikipedia.org dumped 2003-03-17 with terodump