Mushroom chemical defense: Food aversion learning induced by hallucinogenic toxin, muscimol.

Wild animals eat fungi, yet mushroom poisonings in nature are unknown. The opossumDidelphis virginiana readily consumed the toxic mushroomAmanita muscaria, became ill, and then developed an aversion to the fungus. Both the illness and the aversion were due, in part at least, to the toxin muscimol. This appears to be the first demonstration of a mushroom chemical defense against fungivores and the first reported role in nature for an hallucinogen.