Batesian Mimicry - Historical Background

Historical Background

Henry Walter Bates (1825–1892) was an English explorer-naturalist who surveyed the Amazon Rainforest with Alfred Russel Wallace in 1848. While Wallace returned in 1852, Bates remained for over a decade. His field research included collecting almost a hundred species of butterflies from the families Ithomiinae and Heliconiinae, as well as thousands of other insects specimens. In sorting these butterflies into similar groups based on appearance, inconsistencies began to arise. Some appeared superficially similar to others, even so much so that Bates could not tell some species apart based only on wing appearance. However, closer examination of less obvious morphological characters seemed to show that they were not even closely related. Shortly after his return to England he read a paper on his theory of mimicry at a meeting of the Linnean Society of London on the 21st of November 1861, which was then published in 1862 as 'Contributions to an Insect Fauna of the Amazon Valley' in the Transactions of the Linnaean Society. He elaborated on his experiences further in The Naturalist on the River Amazons. These new findings and speculations stimulated long lasting discussion and controversy, not limited to the scientific realm.

Bates put forward the hypothesis that the close resemblance between unrelated species was an antipredator adaptation. He noted that some species showed very striking coloration, and flew in a leisurely manner, almost as if taunting predators to eat them. He reasoned that these butterflies were unpalatable to birds and other insectivores, and were thus avoided by them. He extended this logic to forms that closely resembled such protected species, mimicking their warning coloration but not their toxicity.

This naturalistic explanation fitted well with the recent account of evolution by Alfred Russel Wallace and Charles Darwin, as outlined in his famous 1859 book The Origin of Species. Because this Darwinian explanation required no supernatural forces, it met with considerable criticism from anti-evolutionists, both in academic circles and in the broader social realm. The term mimicry had only been used for people until about 1850, when the word took on a new life in its application to other life forms such as plants and animals. Just as Darwin was the first to put forward a comprehensive explanation for evolution, Bates was the first to elucidate this form of mimicry, and he is thus honored with the term Batesian mimicry. Although other forms have been discovered even in recent times, Batesian mimicry is one of the most commonly occurring and well understood. To many, the word Batesian mimicry and mimicry are treated as the same thing, however it should not be overlooked that Bates described several kinds himself.