Aposematism is a term coined by Edward Bagnall Poulton for Alfred Russel Wallace’s concept of warning colouration. It refers to the signalling of those animals that in some way aesthetically announce that they would be a dangerous choice of prey. When honest, the adaptation benefits both the prey and the predator as the predator avoids potentially toxic, unpleasant in taste or smell, harmful, or aggressive prey, while the prey is obviously allowed to live on.
Initially focused on the colour of the prey the concept also encompasses sound, odour, or any perceivable characteristic. There are cases of non-dangerous species “bluffing” in that they have evolved to signal in the same manner as genuinely dangerous related species.