Venom organ failure. Many caterpillars have defensive venom glands associated with specialized bristles on the body, known as urticating hairs, which can be lethal to humans (e.g., that of the "Lonomia" moth), although the venom's strength varies depending on the species. Bees synthesize and employ an acidic venom (apitoxin) to cause pain in those that they sting to defend their hives and food stores, whereas wasps use a chemically different alkaline venom designed to paralyze prey, so it can be stored alive in the food chambers of their young. The use of venom is much more widespread than just these examples.
Evolution of snake venom contain more than 100 distinct proteins. The composition of this mixture has been shown to vary geographically, and to be related to the prey species available in a certain region. Snake venom has generally evolved very quickly, with changes occurring faster in the venom than in the rest of the organism. Some traditional hypotheses of snake venom evolution have supported the idea that most snakes inject far more venom into their prey than is required to kill them; thus, venom composition would not be subject to natural selection. This is known as the "overkill" hypothesis. However, recent studies of the