aposematisme

Aposematisme is a biological strategy in which organisms advertise their defenses to predators through conspicuous coloration, patterns, or signals. The warning signs indicate that the animal is toxic, unpalatable, venomous, or capable of harm, and they function to reduce the likelihood of an attack. The signals are often learned quickly by predators and can be reinforced by negative experiences, leading to avoidance.

Conspicuous color patterns, such as bright yellows, oranges, reds, and blacks, serve as the most common signals. In many species these patterns are combined with high-contrast contrasts and can be accompanied by other defenses, such as chemical or mechanical deterrents. Producing or carrying toxins is costly to the prey, so aposematic signals are advantageous because they prevent future predation without the risk of injury.

Common groups include poison dart frogs, which sequester potent alkaloids from their diet; monarch butterflies and other milkweed feeders, which become distasteful to predators; and various marine organisms such as certain nudibranchs that store toxins from prey. In some cases, similar warning patterns are shared across species through Müllerian mimicry, where multiple unpalatable species converge on the same signal, while Batesian mimicry describes a non-toxic species imitating an aposematic signal.

Aposematism plays a significant role in predator–prey interactions and can influence the evolution of coloration, behavior, and ecological communities. It is one of several anti-predator strategies and often coexists with other defenses.