African spur-winged geese (
Plectropterus gambensis) become so toxic after eating blister beetles that consuming their flesh can kill a human. Blister beetles (family Meloidae) are toxic due to the presence of a chemical compound called
cantharidin. Cantharidin is a potent toxin that these beetles produce and store in their bodies as a defense mechanism against predators. It acts as a powerful irritant and blistering agent when it comes into contact with skin or mucous membranes. The toxicity of blister beetles serves as a deterrent to potential predators, helping them avoid being eaten.