Chemical defense

Chemical defense is the use of chemical compounds by plants and animals to deter herbivory and predation. Chemical defenses can also be used in competitive interactions to prevent overgrowth or maintain spatial dominance.

In plants

Main article: Plant defense against herbivory

Chemical defense against herbivory is common. The production of capsaicin in many strains of bell peppers is one such defense familiar to humans.

In animals

See also: Aposematism

Chemical defense is most common in insects, but the skunk is a particularly dramatic mammalian example. Other examples include the bombardier beetle which can accurately shoot a predator with a stream of boiling poison, the ornate moth which excretes a frothy alkaloid mixture, and the Pacific beetle cockroach sprays a quinone mixture from modified spiracles.

Marine invertebrate animals also harbor chemical defenses that protect them from predators, particularly tropical marine sponges, gorgonian corals, nudibranch molluscs, and tunicates.