What is "aposematism"

n. (context biology English) An adaptation that warns off potential predators; especially such a warning colouration

Aposematism (from Greek ἀπό apo away, σ̑ημα sema sign) was a new term coined by Edward Bagnall Poulton) for Alfred Russel Wallace's concept of warning color ation . It describes a family of antipredator adaptations in which a warning signal is associated with the unprofitability of a prey item to potential predators. Aposematism always involves an advertising signal. The warning signal may take the form of conspicuous animal coloration , sounds, odours or other perceivable characteristics. Aposematic signals are beneficial for both the predator and prey, since both avoid potential harm.

Aposematism is exploited in Müllerian mimicry, where species with strong defences evolve to resemble one another. By mimicking similarly coloured species, the warning signal to predators is shared, causing them to learn more quickly at less of a cost to each of the species.

Warning signals do not necessarily require that a species actually possesses chemical or physical defences to deter predators. Mimics such as the nonvenomous California mountain kingsnake (Lampropeltis zonata), which has yellow, red, and black bands similar to those of the highly venomous eastern coral snake (Micrurus fulvius), have essentially piggybacked on the successful aposematism of the model. The evolution of a warning signal by a mimicking species that resembles a species that possesses strong defences is known as Batesian mimicry.