Batesian mimicry is a form of protective coloration in which an edible species (the model) resembles a poisonous or otherwise dangerous species (the mimic). It is named after British naturalist Henry Bates, who first described the phenomenon. The mimic benefits from the model’s reputation for being unpalatable or dangerous, while the model benefits from the fact that predators learn to avoid both it and similar-looking species.
The vast majority of Batesian mimics are insects, and the most common models are aposematic animals such as stinging wasps, bees, and ants. However, other types of animals can also serve as models, including snakes, fish, frogs, and mammals. In some cases, multiple species may imitate a single model; for example, many different butterflies may share a single aposematic pattern.
There are two main theories to explain how Batesian mimicry arises. The first is that it is an evolutionary accident; that is, two unrelated species just happen to resemble each other by chance. The second theory is that Batesian mimicry represents an adaptive advantage for both the mimic and the model; that is, it confers some benefit on both groups of organisms. This latter theory is supported by evidence that Batesian mimics tend to be more closely related to each other than they are to their respective models (suggesting common ancestry), and that aposematic patterns often evolve convergently in different groups of organisms (suggesting selection pressure).
Batesian mimicry has been extensively studied since it was first described in 1861. It provides insights into several important topics in evolutionary biology including speciation, convergent evolution, coevolutionary dynamics between predator and prey populations, chemical ecology, and animal behavior.