‘Mimicry’ refers to the copying of one organism by another. Some of the most obvious cases of mimicry are where individuals from different species share a colour pattern. This can be two or more defended species sharing one warning (‘aposematic’) pattern (Mullerian mimicry), and or where a second species copies the warning colours of another, despite lacking any form of defense (Batesian mimicry).
Mimicry differs from camouflage in that it involves sending of signals by the mimic to other organisms whose behaviour the mimic aims to alter, whereas in camouflage or crypsis, an animal tries to not send any signals at all – it is aiming to escape detection.
Mimicry is familiar to us in the warning colours of bees and wasps. Both of these groups of insects defend themselves from predators using stings, and have evolved yellow and black striped patterns to warn potential predators that they are not suitable prey. The bees and wasps are mimicking each others’ yellow and black stripes. We call this type of mimicry, where the species involved are all defended, Mullerian mimicry after its discovery by Fritz Muller in 1878. Mullerian mimicry helps predators to quickly learn to avoid unsuitable prey, and defended species quickly converge on a pattern of warning colours.
Not all mimics are defended – some species, such as hoverflies, are ‘cheats.’ Hoverflies have yellow and black stripes, similar to wasps, but cannot sting. If birds mistake a fly’s for a bee or a wasp, the fly will avoid being eaten. Over time, this will lead to evolution of a remarkable similarity between the mimic (hoverfly) and the model (bees and wasps). We call this kind of mimicry, where one non-defended species (the mimic) gains protection by copying a defended species (the model) Batesian mimicry, after the naturalist H W Bates who described it in 1862.