mimicry, in biology, the advantageous resemblance of one species to another, often unrelated, species or to a feature of its own environment. (When the latter results from pigmentation it is classed as protective coloration.) Mimicry serves either to protect the mimic from its predators, as when the model is inedible or dangerous, or to deceive its prey (e.g., certain ant-eating spiders that themselves resemble ants). Mimicry occurs in both plants and animals but is most prevalent among insects, particularly butterflies and moths. The first scientific studies on the subject were published by English naturalists H. W. Bates (1862) and A. R. Wallace (1865). The Batesian theory is based on the operation of natural selection: if, say, a harmless snake acquires a deceptive resemblance to a poisonous variety it is then more likely to escape its predators and thus to survive and propagate, producing offspring with the same appearance. Examples of mimicry are the resemblance of the viceroy butterfly to the monarch butterfly, which is repugnant to birds; harmless nettles that resemble stinging nettles; and the many fishes, crabs, and slugs of the Sargasso Sea that resemble the floating seaweed masses they inhabit.

Similarity between organisms that confers a survival advantage on one. In Batesian mimicry, an organism lacking defenses mimics a species that does have defenses. In Müllerian mimicry, all species in a group are similar even though all individually have defenses. In aggressive mimicry, a predatory species mimics a benign species so that it can approach its prey without alarming it, or a parasitic species mimics its host. Some plant species mimic the colour patterns and scents of animals for the purposes of pollination and dispersal. Mimicry differs from camouflage in that camouflage hides the organism, whereas mimicry benefits the organism only if the organism is detected.

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