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.
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.
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.
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.
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 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.
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, the mimic effectively copies the coloration of an aposematic animal, known as the model, to deceive predators into behaving as if it were distasteful. The success of this dishonest display depends on the level of toxicity of the model and the abundance of the model in the geographical area. The more toxic the model is, the more likely it is that the predator will avoid the mimic. The abundance of the model species is also important for the success of the mimic because of frequency dependent selection. When the model is abundant, mimics with imperfect model patterns or slightly different coloration from the model are still avoided by predators. This is because the predator has a strong incentive to avoid potentially lethal organisms, given the likelihood of encountering one. However, in areas where the model is scarce or locally extinct, mimics are driven to accurate aposematic coloration. This is because predators attack imperfect mimics more readily where there is little chance that they are the model species. Frequency dependent selection may also have driven Batesian mimics to become polymorphic in rare cases where a single genetic switch controls appearance, as in the swallowtail butterflies (the Papilionidae) such as the pipevine swallowtail.
Batesian mimicry is a case of protective or defensive mimicry, where the mimic does best by avoiding confrontations with the signal receiver. It is a disjunct system, which means that all three parties are from different species. Batesian mimicry stands in contrast to other forms such as aggressive mimicry, where the mimic profits from interactions with the signal receiver. One such case of this is in fireflies, where females of one species mimic the mating signals of another species, deceiving males to come close enough for them to eat. Mimicry need not involve a predator at all though. Such is the case in dispersal mimicry, where the mimic once again benefits from the encounter. For instance, some fungi have their spores dispersed by insects by smelling like carrion. In protective mimicry, the meeting between mimic and dupe is not such a fortuitous occasion for the mimic, and the signals it mimics tend to lower the probability of such an encounter.
A case somewhat similar to Batesian mimicry is that of mimetic weeds, which imitate agricultural crops. In weed or Vavilovian mimicry, the weed survives by having seeds which winnowing machinery identifies as belonging to the crop. Vavilovian mimicry is not Batesian, because man and crop are not enemies. By contrast, a leaf-mimicking plant, the chameleon vine, employs Batesian mimicry by adapting its leaf shape and colour to match that of its host to deter herbivores from eating its edible leaves.
Another analogous case within a single species has been termed Browerian mimicry (after Lincoln P. Brower and Jane Van Zandt Brower). This is a case of bipolar (only two species involved) automimicry; the model is the same species as its mimic. Equivalent to Batesian mimicry within a single species, it occurs when there is a palatability spectrum within a population of harmful prey. For example, monarch (Danaus plexippus) caterpillars feed on milkweed species of varying toxicity. Some feed on more toxic plants, and store these toxins within themselves. The more palatable caterpillars thus profit from the more toxic members of the same species.
Another important form of protective mimicry is Müllerian mimicry, discovered by and named after the naturalist Fritz Müller. In Müllerian mimicry both model and mimic are aposematic, so mimicry may be mutual, does not necessarily[a] constitute a bluff or deception, and as in the wasps and bees may involve many species in a mimicry ring.
In imperfect Batesian mimicry, the mimics do not exactly resemble their models. Many reasons have been suggested for this. Imperfect mimics may simply be evolving towards perfection. They may gain advantage from resembling multiple models at once. Humans may evaluate mimics differently from actual predators. Mimics may confuse predators by resembling both model and nonmimic at the same time (satiric mimicry). Kin selection may enforce poor mimicry. The selective advantage of better mimicry may not outweigh the advantages of other strategies like thermoregulation or camouflage. Only certain traits may be required to deceive predators; for example, tests on the sympatry/allopatry border (where the two are in the same area, and where they are not) of the mimic Lampropeltis elapsoides and the model Micrurus fulvius showed that color proportions in these snakes were important in deceiving predators, but that the order of the colored rings was not.
Predators may identify their prey by sound as well as sight; mimics have accordingly evolved to deceive the hearing of their predators. Bats are nocturnal predators that rely on echolocation to detect their prey. Some potential prey are unpalatable to bats, and produce an ultrasonic aposematic signal, the auditory equivalent of warning coloration. In response to echolocating red bats and big brown bats, tiger moths such as Cycnia tenera produce warning sounds. Bats learn to avoid the harmful moths, but similarly avoid other species such as some pyralid moths that produce such warning sounds as well. Acoustic mimicry complexes, both Batesian and Müllerian, may be widespread in the auditory world.
[Consider the case where one monarch caterpillar is feeding on cardenolide-containing milkweed, the other not], with one being completely potent with regard to cardiac glycoside toxicity, the second not. The first will fit all of the characteristics for warning coloration, the second not. In fact, the second butterfly is a harmless Batesian mimic of the first, even though both belong to the same species. L. Brower, J. Brower, and Corvino (1967) have termed this phenomenon automimicry, though others have suggested that Browerian mimicry would be a better term (Pasteur, 1972; Bees, 1977; Rothschild, 1979). Note that all of the antagonisms raised by Batesian mimicry will arise, but now the model and the mimic are conspecific.
Ant mimicry or myrmecomorphy is mimicry of ants by other organisms. Ants are abundant all over the world, and potential predators that rely on vision to identify their prey, such as birds and wasps, normally avoid them, because they are either unpalatable or aggressive. Spiders are the most common ant mimics. Additionally, some arthropods mimic ants to escape predation (protective mimicry), while others mimic ants anatomically and behaviourally to hunt ants in aggressive mimicry.
In Wasmannian mimicry, mimic and model live commensally together; in the case of ants, the model is an inquiline in the ants' nest. Wasmannian mimics may also be Batesian or aggressive mimics. To overcome ants' powerful defences, mimics may imitate ants chemically with ant-like pheromones, visually (as in Batesian mimicry), or by imitating an ant's surface microstructure for tactile mimicry.Chemical mimicry
Chemical mimicry (also referred to as Molecular mimicry) is a type of biological mimicry, involving the use of chemicals to dupe an operator. A chemical mimic dupes an operator (e.g. a predator) by showing an adaptive chemical resemblance to an object of its environment and as a consequence receives selective advantage. In all cases of chemical mimicry it has been found that the mimicking species is the only species to benefit from the reaction with either costs or no effect on the duped species. This is by adapting to produce chemicals (ex: allomones, pheromones, odours, etc.) that will cause a desirable behavioural reaction in the species being deceived and a selective advantage to the mimic. Chemical mimicry exists within many of the different forms of mimicry such as aggressive, protective, Batesian, and Müllerian mimicry and can involve a number of different senses. Mimicking semiochemicals, which cannot be seen, make up some of the most widely used forms of chemical mimicry and is therefore less apparent than more visual forms. As a result of this, this topic has been relatively neglected in research and literature. Two examples of organisms displaying chemical mimicry include the mimicking of Noctuid pheromones by Bolas spiders in order to draw prey to the spider’s location and the duping of insects within their own nests by mimicking their odours in order to enter and hide within the nest undetected. It is important to note that in all forms of mimicry the mimicking organism is not conscious of the deceit used and does not act intentionally to trick other organisms.Cinereous mourner
The cinereous mourner (Laniocera hypopyrra) is a species of bird in the family Tityridae. The term cinereous describes its colouration. It has traditionally been placed in the cotinga family, but evidence strongly suggest it is better placed in Tityridae, where now placed by SACC. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela.
Its natural habitat is subtropical or tropical moist lowland forests.
French naturalist Louis Jean Pierre Vieillot described the species in 1817.
Nestlings of this species are orange with long filoplumes that end in white tips and have a resemblance to hairy caterpillars of a moth belonging to the family Megalopygidae. The young birds move their heads slowly from side to side which are thought to enhance the impression by resembling a moving caterpillar. It is thought that this may be the first case of Batesian mimicry involving a harmless bird mimic and a toxic insect model.Cleaning symbiosis
Cleaning symbiosis is a mutually beneficial association between individuals of two species, where one (the cleaner) removes and eats parasites and other materials from the surface of the other (the client). Cleaning symbiosis is well-known among marine fish, where some small species of cleaner fish, notably wrasses but also species in other genera, are specialised to feed almost exclusively by cleaning larger fish and other marine animals. Other cleaning symbioses exist between birds and mammals, and in other groups.
Cleaning behaviour was first described by the Greek historian Herodotus in about 420 BC, though his example (birds serving crocodiles) appears to occur only rarely.
The role of cleaning symbioses has been debated by biologists for over thirty years. Some believe that cleaning represents selfless co-operation, essentially pure mutualism, increasing the fitness of both individuals. Others such as Robert Trivers hold that it illustrates mutual selfishness, reciprocal altruism. Others again believe that cleaning behaviour is simply one-sided exploitation, a form of parasitism.
Cheating, where either a cleaner sometimes harms its client, or a predatory species mimics a cleaner, also occurs. Predatory cheating is analogous to Batesian mimicry, as where a harmless hoverfly mimics a stinging wasp, though with the tables turned. Some genuine cleaner fish, such as gobies and wrasse, have the same colours and patterns, in an example of convergent evolution. Mutual resemblance among cleaner fish is analogous to Müllerian mimicry, as where stinging bees and wasps mimic each other.Danaus chrysippus
Danaus chrysippus, also known as the plain tiger or African queen, is a medium-sized butterfly widespread in Asia, Australia and Africa. It belongs to the Danainae subfamily of the brush-footed butterfly family Nymphalidae. Danainae primarily consume plants in the genus Asclepias, more commonly called milkweed. Milkweed contains toxic compounds, cardenolides, which are often consumed and stored by many butterflies. Because of their emetic properties, the plain tiger is unpalatable to most predators. As a result, the species' coloration is widely mimicked by other species of butterflies. The plain tiger inhabits a wide variety of habitats, although it is less likely to thrive in jungle-like conditions and is most often found in drier, wide-open areas.D. chrysippus encompasses three main subspecies: D. c. alcippus, D. c. chrysippus, and D. c. orientis. These subspecies are found concentrated in specific regions within the larger range of the entire species.The plain tiger is believed to be one of the first butterflies depicted in art. A 3500-year-old Egyptian fresco in Luxor features the oldest known illustration of this species.Deception in animals
Deception in animals is the transmission of misinformation by one animal to another, of the same or different species, in a way that propagates beliefs that are not true. Deception in animals does not automatically imply a conscious act, but can occur at different levels of cognitive ability.
Mimicry and camouflage enable animals to appear to be other than they are. Prey animals may appear as predators, or vice versa; both predators and prey may be hard to see (crypsis), or may be mistaken for other objects (mimesis). In Batesian mimicry, harmless animals may appear to be distasteful or poisonous. In automimicry, animals may have eyespots in less important parts of the body than the head, helping to distract attack and increase the chance of survival.
In more active forms of anti-predator adaptation, animals may feign death when they detect a predator, or may quickly conceal themselves or take action to distract a predator, such as when a cephalopod releases ink. In deimatic behaviour, a harmless animal adopts a threatening pose or displays startling, brightly coloured parts of its body to startle a predator or rival.
Some animals may use tactical deception, with behaviour that is deployed in a way that other animals misinterpret what is happening to the advantage of the agent. Some of the evidence for this is anecdotal, but in the great apes in particular, experimental studies in ethology suggest that deception is actively practised by some animals.Defense in insects
Insects have a wide variety of predators, including birds, reptiles, amphibians, mammals, carnivorous plants, and other arthropods. The great majority (80–99.99%) of individuals born do not survive to reproductive age, with perhaps 50% of this mortality rate attributed to predation. In order to deal with this ongoing escapist battle, insects have evolved a wide range of defense mechanisms. The only restraint on these adaptations is that their cost, in terms of time and energy, does not exceed the benefit that they provide to the organism. The further that a feature tips the balance towards beneficial, the more likely that selection will act upon the trait, passing it down to further generations. The opposite also holds true; defenses that are too costly will have a little chance of being passed down. Examples of defenses that have withstood the test of time include hiding, escape by flight or running, and firmly holding ground to fight as well as producing chemicals and social structures that help prevent predation.
One of the best known modern examples of the role that evolution has played in insect defenses is the link between melanism and the peppered moth (Biston betularia). Peppered moth evolution over the past two centuries in England has taken place, with darker morphs becoming more prevalent over lighter morphs so as to reduce the risk of predation. However, its underlying mechanism is still debated.Dryadula phaetusa
Dryadula is a monotypic genus of the butterfly family Nymphalidae. Its single species, Dryadula phaetusa, known as the banded orange heliconian, banded orange, or orange tiger, is native from Brazil to central Mexico, and in summer can be found rarely as far north as central Florida. Its wingspan ranges from 86 to 89 mm, and it is colored a bright orange with thick black stripes in males and a duller orange with fuzzier black stripes in females.
It feeds primarily on the nectar of flowers and on bird droppings; its caterpillar feeds on passion vines including Passiflora tetrastylis. It is generally found in lowland tropical fields and valleys.
This species is unpalatable to birds and belongs to the "orange" Batesian mimicry complex.Gaeana
Gaeana is a genus of cicadas, most members of which have colourful marking on their forewings, found across tropical and temperate Asia. Their bright wing patterns have been hypothesized as being a case of Batesian mimicry where the toxic models may be day-flying moths of the families Zygaenidae and Arctiidae. It is closely related to the genus Tosena but is differentiated by the exposed tympanum and lacks spines on the sides of the pronotum.Hypolimnas
Hypolimnas is a genus of tropical brush-footed butterflies commonly known as eggflies or diadems. The genus contains approximately 23 species, most of which are found in Africa, Asia, and Oceania. One species, the Danaid eggfly (H. misippus), is noted for its exceptionally wide distribution across five continents; it is the only Hypolimnas species found in the Americas.
Eggflies are known for their marked sexual dimorphism and Batesian mimicry of poisonous milkweed butterflies (Danainae). For example, the Danaid eggfly mimics Danaus chrysippus while the great eggfly (H. bolina) mimics the Australian crow (Euploea core). In each case, the eggfly mimics the danainid's markings, thus adopting the latter's distasteful reputation to predators without being poisonous itself.Locomotor mimicry
Locomotor mimicry is a subtype of Batesian mimicry in which animals avoid predation by mimicking the movements of another species phylogenetically separated. This can be in the form of mimicking a less desirable species or by mimicking the predator itself. Animals can show similarity in swimming, walking, or flying of their model animals.
The complex interaction between mimics, models, and predators (sometimes called observers) can help explain similarities amongst species beyond ideas that emerge from evolutionary comparative approaches. In terms of overall movement, the continuous locomotor mimicry of a species that differs anatomically from the mimic may increase metabolic cost. However, the benefit of avoiding predation appears to outweigh the increased energy cost, because mimicking animals tend to have higher survival rates than their non-mimicking counterparts.Mimicry in vertebrates
In evolutionary biology, mimicry in vertebrates is mimicry by a vertebrate of some model (an animal, not necessarily a vertebrate), deceiving some other animal, the dupe. Mimicry differs from camouflage as it is meant to be seen, while animals use camouflage to remain hidden. Visual, olfactory, auditory, biochemical, and behavioral modalities of mimicry have been documented in vertebrates.There are few well-studied examples of mimicry in vertebrates. Still, many of the basic types of mimicry apply to vertebrates, especially among snakes. Batesian mimicry is rare among vertebrates but found in some reptiles (particularly snakes) and amphibians. Müllerian mimicry is found in some snakes, birds, amphibians, and fish. Aggressive mimicry is known in some vertebrate predators and parasites, while certain forms of sexual mimicry are distinctly more complex than in invertebrates.Myrichthys colubrinus
Myrichthys colubrinus, the banded snake eel, ringed snake eel or harlequin snake eel, is a snake eel from the Indo-Pacific. It occasionally makes its way into the aquarium trade. It grows to a size of 97 cm (38 in) in length.The ringed snake eel resembles the venomous sea snake, Laticauda colubrina which is a form of Batesian mimicry. It also adjusts its behaviour to swim freely during the day, whereas other snake eels tend to stay hidden and roam at night.Müllerian mimicry
Müllerian mimicry is a natural phenomenon in which two or more unprofitable (often, distasteful) species, that may or may not be closely related and share one or more common predators, have come to mimic each other's honest warning signals, to their mutual benefit, since predators can learn to avoid all of them with fewer experiences. It is named after the German naturalist Fritz Müller, who first proposed the concept in 1878, supporting his theory with the first mathematical model of frequency-dependent selection, one of the first such models anywhere in biology.Müllerian mimicry was first identified in tropical butterflies that shared colourful wing patterns, but it is found in many groups of insects such as bumblebees, and other animals including poison frogs and coral snakes. The mimicry need not be visual; for example, many snakes share auditory warning signals. Similarly, the defences involved are not limited to toxicity; anything that tends to deter predators, such as foul taste, sharp spines, or defensive behaviour can make a species unprofitable enough to predators to allow Müllerian mimicry to develop.
Once a pair of Müllerian mimics has formed, other mimics may join them by advergent evolution (one species changing to conform to the appearance of the pair, rather than mutual convergence), forming mimicry rings. Large rings are found for example in velvet ants. Since the frequency of mimics is positively correlated with survivability, rarer mimics are likely to adapt to resemble commoner models, favouring both advergence and larger Müllerian mimicry rings. Where mimics are not strongly protected by venom or other defences, honest Müllerian mimicry grades into bluffing Batesian mimicry.Necydalis mellita
Necydalis mellita is a longhorn beetle in the family Cerambycidae.
The very long and slender body, colouration, the short elytra, exposing the wings and the constricted pronotum of beetles in this genus are an instance of Batesian mimicry.Poecilanthrax willistoni
Poecilanthrax willistoni, Williston's bee fly or sand dune bee fly, is a member of the Bombyliidae insect family. This family includes the bee flies, true flies that have developed Batesian mimicry characteristics to avoid predators. That is, they look like bees because that helps them avoid bee-wary predators, but they lack stingers.
P. willistoni also has larvae that act as parasitoids on other insect species. They drop their eggs strategically so that when the larvae emerge they can easily locate and consume grubs and caterpillars. The bee fly sometimes propels its eggs into holes where beetles live, and when the bee fly's eggs hatch, the larvae attack and eat the beetles' offspring. This species of bee fly lives on sand dunes, and so parasitizes sand dune insect species.
This species at a glance resembles a bee, fumbling flowers for nectar and sporting alternating orange and black bars down its abdomen. Unlike a bee, however, it has large red eyes and long, swept-back wings that it holds out from its body.Sesiidae
The Sesiidae or clearwing moths are a diurnal moth family in the order Lepidoptera known for their Batesian mimicry in both appearance and behaviour of various Hymenoptera.
The family consists of 151 genera spread over two subfamilies, containing in total 1370 species and 50 subspecies, most of which occur in the tropics, though there are many species in the Holarctic region as well, including over a hundred species known to occur in Europe.Spilomyia
Spilomyia is a genus of hoverflies. Many species in the genus show Batesian mimicry of wasp models, including black and yellow patterns and modified antenna shape.Viceroy (butterfly)
The viceroy (Limenitis archippus) is a North American butterfly that ranges through most of the contiguous United States as well as parts of Canada and Mexico. The westernmost portion of its range extends from the Northwest Territories along the eastern edges of the Cascade Range and Sierra Nevada mountains, southwards into central Mexico. Its easternmost range extends along the Atlantic and Gulf coasts of North America from Nova Scotia into Texas.It was long been thought to be a Batesian mimic of the monarch butterfly, but since the viceroy is also distasteful to predators, it is now considered a Müllerian mimic instead.
The viceroy was named the state butterfly of Kentucky in 1990.