<P> Batesian mimicry is a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both . It is named after the English naturalist Henry Walter Bates, after his work on butterflies in the rainforests of Brazil . </P> <P> Batesian mimicry is the most commonly known and widely studied of mimicry complexes, such that the word mimicry is often treated as synonymous with Batesian mimicry . There are many other forms however, some very similar in principle, others far separated . It is often contrasted with Müllerian mimicry, a form of mutually beneficial convergence between two or more harmful species . However, because the mimic may have a degree of protection itself, the distinction is not absolute . It can also be contrasted with functionally different forms of mimicry . Perhaps the sharpest contrast here is with aggressive mimicry, where a predator or parasite mimics a harmless species, avoiding detection and improving its foraging success . </P> <P> The imitating species is called the mimic, while the imitated species (protected by its toxicity, foul taste or other defenses) is known as the model . The predatory species mediating indirect interactions between the mimic and the model is variously known as the (signal) receiver, dupe or operator . By parasitizing the honest warning signal of the model, the Batesian mimic gains an advantage, without having to go to the expense of arming itself . The model, on the other hand, is disadvantaged, along with the dupe . If impostors appear in high numbers, positive experiences with the mimic may result in the model being treated as harmless . At higher frequency there is also a stronger selective advantage for the predator to distinguish mimic from model . For this reason, mimics are usually less numerous than models, an instance of frequency dependent selection . Some mimetic populations have evolved multiple forms (polymorphism), enabling them to mimic several different models and thereby to gain greater protection . Batesian mimicry is not always perfect . A variety of explanations have been proposed for this, including limitations in predators' cognition . </P> <P> While visual signals have attracted most study, Batesian mimicry can employ deception of any of the senses; some moths mimic the ultrasound warning signals sent by unpalatable moths to bat predators, constituting auditory Batesian mimicry . </P>

Describe the differences between batesian and mullerian mimicry