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 21 November 1861, which was then published in 1862 as 'Contributions to an Insect Fauna of the Amazon Valley' in the society's Transactions. He elaborated on his experiences further in The Naturalist on the River Amazons. 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 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. Aposematism Most living things have predators and therefore are in a constant evolutionary arms race to develop antipredator adaptations, while the predator adapts to become more efficient at defeating the prey's adaptations. Some organisms have evolved to make detection less likely, for example by nocturnality and camouflage. Others have developed chemical defences such as the deadly toxins of certain snakes and wasps, or the noxious scent of the skunk. Such prey often send clear and honest warning signals to their attackers with conspicuous aposematic (warning) patterns. The brightness of such warning signs is correlated with the level of toxicity of the organism. In Batesian mimicry,