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The concept of biological mimicry was introduced by Henry Bates in 1862 to describe the phenomenon in which two or more unrelated organisms resemble each other closely, but where the resemblance is not a homology or an analogy. Bates observed two butterflies, one of which was distasteful to bird predators and one which was not. He suggested that the butterfly which was good to eat bore similar markings to the inedible species because this would deter predators from eating it. Mimicry thus depends upon an individual (the receiver) being deceived by the similarity between two species, one a mimic, the other a model. Typically the mimetic relationship involves a one-sided benefit to the mimic, the selective pressure being exerted by the receiver.
Although mimicry is commonly based on visual appearance, sound, smell and behaviour may be copied, provided the receiver acts in the same way to both the model and the mimetic signals. Mimicry should be distinguished from the phenomenon of camouflage, which involves seeking not to be noticed at all. Fritz Müller showed in 1870 that two species might mimic one another in a fashion that conferred mutual benefit; this is the case with coral snakes, all of which are similar in appearance, and many of which are poisonous. The predator must attack to discover that the snake is poisonous and, providing it survives, it will subsequently avoid all species in the coral snake group. Mimicry may occur within a species—a male bee, for example, which has no sting, is protected by the knowledge among animals that female bees, which look similar, do sting. RB
See also ethology; symbiosis.Further reading W. Wickler, Mimicry. |
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