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DRAFT - Arthropod Mimicry

    Mimicry in arthropods is very interesting to me. I think it is a very creative and unusual adaptation that has been adopted by many creatures for varying reasons. Some mimic other species for predation, others to avoid predation, some for camouflage, some use reverse mimicry, and still others for mutual benefits between the mimic and the model. This article will explore the varying types of mimicry and attempt to explain the benefits of such adaptations and/or behavior plus show examples of mimics posted here on BugGuide.

    Common terminology used in this article are as follows. The species that has adapted its appearance, behavior, scent, or vocalizations to resemble common perceived characteristics of another organism is known as a "mimic". The organism being mimicked is called the "model". The organism being fooled or deceived is called the "Dupe".

    In reading and researching about this topic it became immediately apparent that there is much more to mimicry than meets the eye (pun intended) :-). There are at least ten distinct types of mimicry that I've found and read about and I'll try to explain them, as I understand them, to the best of my ability or provide quotes and citations.

    First a little history. There has been some debate as to why and/or how species have come to mimic other species. Charles Darwin and his theory of natural selection is one example. His theory centered mainly around individuals, rather than entire groups, due to competition between individuals of the same species. So then if individuals have to compete but are all unique then some individuals over time will develop variations that will ultimately help them survive. This will also give them more opportunity to mate and produce young and a greater number of young. The helpful variations of the parents will then be inherited by the young which they will then benefit from also. Eventually, given enough time, these successful variations will spread through the species population, therefore effectively changing the species. This is my own feeble interpretation. Obviously there is much more to this theory than this but it's a fair overview.

    Another evolutionist by the name of Alfred Russel Wallace was in agreement with Darwin up to a point. He had similar ideas about why species are the way they are but with some significant differences. Wallace apparently thought selection acted on groups or species rather than individuals but apparently it is generally accepted that Darwin was right that selection acts primarily on individuals. Darwin said that competition within populations of species was the cause of them evolving but Wallace believed the species meeting the demands of a change in their environment was the reason. From what I can gather these two men disagreed more and more as time went on. They even went so far as to argue about human evolution and later Wallace seemed to get really out there with some of his ideas.

    There is also another paper I read by Victoria N. Alexander called "Neutral Evolution and Aesthetics: Vladimir Nabokov and Insect Mimicry" written, I believe, around 2001. It talks a lot about "Teleology", which is the idea that the development of the universe has had a direction and that direction is towards the perfection of man. But, it also makes some interesting points about why critters mimic other critters. It deals mainly with the ideas of Vladimir Nabokov, who is probably better known for his literary achievements but was also said to have a "gift for science". His theories centered around accidental functionality, coincidental patterns, and mimicry. His ideas said that though there are physical mechanisms for a spiral galaxy, for example, to be a "spiral", constellations like the Big Dipper are just accidental, coincidental, or just a chance pattern. In this same way he says that insect mimicry is mostly coincidental. He uses the examples of the Viceroy butterfly as compared to a Monarch and asks what practical purpose the Viceroy would have for looking like a Monarch. The first thing I think of is that Monarchs are reported to be bitter tasting and undesirable so the Viceroy mimics the Monarch to avoid being eaten. The paper says that Nabokov believed that somewhere in the Viceroys past a variation slightly resembling a Monarch emerged. It was successful because the patterns looked a little like a Monarch so predators left it alone and over time this variation continued because it wasn't being eaten. Gradually it started to look more and more like a Monarch and the more it did the more it flourished. He said that this mimicry as well as others, like the "dead-leaf butterfly", involve many elements of chance.

    There are other theories out there for why mimics "mimic". Some theories are more widely "accepted" than others but they are still all just theories. Personally for me, I just think it's cool regardless of how or why.

    As mentioned previously there are around ten types of mimicry. They are described below.

Batesian - from Wikipedia(1) - "In Batesian mimicry the mimic shares signals similar to the model, but does not have the attribute that makes it unprofitable to predators (e.g. unpalatability). In other words, a Batesian mimic is a sheep in wolf's clothing. It is named after Henry Walter Bates, an English naturalist whose work on butterflies in the Amazon rainforest (including Naturalist on the River Amazons) was pioneering in this field of study. Mimics are less likely to be found out when in low proportion to their model, a phenomenon known as negative frequency dependent selection which applies in most other forms of mimicry as well."
Below are examples of Batesian mimics of wasps and bees because they resemble the wasp, but are not capable of stinging. A predator that has learned to avoid the wasp or bee would similarly avoid the moths.
     

Müllerian - from Wikipedia(1) - "Müllerian mimicry describes a situation where two or more species have very similar warning or aposematic signals and both share genuine anti-predation attributes (e.g. being unpalatable). At first Bates could not explain why this should be so; if both were harmful why did one need to mimic another? The German naturalist Fritz Müller put forward the first explanation for this phenomenon: If two species were confused with one another by a common predator, individuals in both would be more likely to survive. This type of mimicry is unique in several respects. Firstly, both the mimic and the model benefit from the interaction, which could thus be classified as mutualism in this respect. The signal receiver is also advantaged by this system, despite being deceived regarding species identity, as it avoids potentially harmful encounters. The usually clear identity of mimic and model are also blurred. In cases where one species is scarce and another abundant, the rare species can be said to be the mimic. When both are present in similar numbers however it is more realistic to speak of each as comimics than of a distinct 'mimic' and 'model' species, as their warning signals tend to converge toward something intermediate between the two. Another theoretical problem comes up when one considers that the two species may exist on a continuum from the harmless to the highly noxious, raising the question of where Batesian mimicry ends and Müllerian convergence begins."

  from Britannica Online(2) - "a form of biological resemblance in which two or more unrelated noxious, or dangerous, organisms exhibit closely similar warning systems, such as the same pattern of bright colours. According to the widely accepted theory advanced in 1878 by the German naturalist Fritz Müller, this resemblance, although differing from the better-known Batesian mimicry (in which one organism is not noxious), should be considered mimicry nonetheless, because a predator that has learned to avoid an organism with a given warning system will avoid all similar organisms, thus making the resemblance a protective mechanism."

  from wiseGEEK(3) - "Mullerian mimicry is a biological phenomenon whereby two harmful species, which may not be closely related, come to mimic each other in their external appearance to scare away predators. These animals may have a common predator, and therefore experience mutual gain when their body patterns are associated with danger in the eyes of the predator, causing them to be passed by. The most commonly cited example of Mullerian mimicry is in butterflies, various lineages of which have similar colorful patterns on their wings to help scare away predators. The butterfly's actual repel mechanism is its foul taste.

The basis of many types of mimicry is aposematism -- the strategy whereby dangerous organisms (wasps, poison frogs, etc.) signal their defenses to predators through gaudy colors like bright yellow, orange, purple, or red. This is a strategy naturally opposed to crypsis, where the organism attempts to survive by attracting as little attention as possible, as in camouflage. Some organisms even employ both, trying to look inconspicuous until they are noticed, at which point they flash warning colors or symbols. This dual strategy is found among many snakes and amphibians.

The concept of Mullerian mimicry was first proposed in 1878 by Fritz Muller, a German naturalist and early proponent of Darwin's theory of evolution. In the immediate decades after the theory was published, naturalists spent a lot of time trying to explain certain seeming holes in the theory, reconciling it with field observations. A British naturalist, William Bates, studied Brazilian butterflies and came up with the concept of Batesian mimicry, whereby a harmless species mimics a harmful species, fooling predators into believing it is harmful. This showed how independently evolving lineages could come to resemble one another through natural selection. What was confusing were why harmful species came to resemble one another as well. This question was answered by Muller with his proposal of Mullerian mimicry."
Good examples here for butterflies would be the Monarch (1st pic) and Viceroy (2nd pic).
 

Emsleyan/Mertensian - from Wikipedia(1) - "Emsleyan or Mertensian mimicry describes unusual cases where deadly prey mimic a less dangerous species. It was first proposed by Emsley as a possible answer for the problem of Coral Snake mimicry in the New World. It was elaborated on by the German biologist Wolfgang Wickler in a chapter of Mimicry in Plants and Animals, who named it after the German herpetologist Robert Mertens. Sheppard points out that Hecht and Marien put forward a similar hypothesis ten years earlier.

This scenario is a little more difficult to understand, as in other types of mimicry it is usually the most harmful species that is the model. But if a predator dies, it cannot learn to recognize a warning signal, e.g. bright colors in a certain pattern. In other words, there is no advantage in being aposematic for an organism that is likely to kill any predator it succeeds in poisoning; such an animal would rather profit from being camouflaged, to avoid attacks altogether. If, however, there is some other species that is harmful but not deadly as well as aposematic, the predator may learn to recognize its particular warning colors and avoid such animals. A deadly species will then profit by mimicking the less dangerous aposematic organism, if this results in less attacks than camouflage would.

The exception here, ignoring any chance of animals learning by watching a conspecific die (see Jouventin et al. for a discussion of observational learning and mimicry), is the possibility of not having to learn that it is harmful in the first place: instinctive genetic programming to be wary of certain signals. In this case, other organisms could benefit from this programming, and Batesian or Müllerian mimics of it could potentially evolve. In fact, it has been shown that some species do have an innate recognition of certain aposematic warnings. Hand-reared Turquoise-browed Motmots (Eumomota superciliosa), avian predators, instinctively avoid snakes with red and yellow rings. Other colors with the same pattern, and even red and yellow stripes with the same width as rings, were tolerated. However, models with red and yellow rings were feared, with the birds flying away and giving alarm calls in some cases. This provides one alternative explanation to Mertensian mimicry."

  from web article on Henry Walter Bates(4) - "In Mertensian mimicry, a palatable and a highly toxic species both come to resemble a moderately toxic model. Many butterflies are "automimics": one may have false eyespots on its wings, say, to fool birds into snapping at a part of its body that it can better afford to lose than its head. Camouflage and crypsis-keeping a low profile-are favorite survival strategies in the rain forest: moths simulate leaves, and snakes look like vines. It is as if the rain forest were a dangerous, riotous carnival, and everyone who would dance in it must wear a costume."

  from Distance Learning article(5) - "A variant of Batesian mimicry is Mertensian mimicry, in which a non-venomous animal resembles a moderately poisonous instead of a highly venomous one. The idea is that a predator will more easily survive a contact with a moderately venomous animal than with a highly venomous animal. A learning process is thus stimulated, without being punished by death. Naive predators will then be less common, which benefits the prey."

  from The Conservation Report(6) - "Mertensian mimicry occurs when both a harmless and harmful species model from a moderately harmful species. For example, “some Milk Snake (Lampropeltis triangulum) subspecies (harmless), the moderately toxic False Coral Snakes (genus Erythrolamprus), and the deadly Coral Snakes all have a red background color with black and white/yellow stripes, [and] in this system, both the milk snakes and the deadly coral snakes are mimics, whereas the false coral snakes are the model.”

Folk culture has developed rhymes to help differentiate the venomous coral snake from non-venomous species. For example: Red and yellow, kill a fellow; red and black, venom lack. However, these folk rhymes only work in certain areas and with some species, since variability in color patterns amongst the poisonous coral snakes and non-venomous species occur. According to Wikipedia, these folk rhymes “only reliably [apply] to coral snakes native to North America: Micrurus fulvius (Eastern or common), Micrurus tener (Texas), and Micruroides euryxanthus (Arizona), found in the southern and eastern United States, [so] coral snakes found in other parts of the world can have distinctly different patterns, have red bands touching black bands, have only pink and blue banding, or have no banding at all.”"

  I haven't read much in the way of arthropods for this type. However, I believe things such as spiders mimicking ants would fall into this category because it's a predator mimicking a less imposing ant.
  

Wasmannian - from Wikipedia(1) - "Wasmannian mimicry refers to cases where the mimic resembles a model along with which it lives (inquiline) in a nest or colony. Most of the models here are social insects such as ants, termites, bees and wasps."

  from Microscopy-UK - ANTS, BEETLES AND SPIDERS by David B. Richman(7) - "Finally, we have Wasmannian mimicry, a more specialized form of mimicry, in which organisms that mimic ants are also inhabitants of the ant nest. Another possibility, so far without a discoverer's name applied to it, would be that spiders resemble ants or beetles in order to get "lost in the crowd" and thus avoid predators. A similar effect is called schooling in fish.
Unfortunately, these examples are not as clear-cut as we would like. The examples of one form of mimicry have, with study, often been shown to be really examples of another form. For years the monarch butterfly and its mimic, the viceroy, where thought to be involved in Batesian mimicry. However, more recently analyzed data have indicated that the viceroy is also unpalatable and thus the pair is an example of Müllerian mimicry. The mimicry of ants and beetles by spiders is also, on its face, not easily categorized. It is especially difficult to tell whether the spiders are using aggressive, "schooling" or Batesian mimicry, as spiders could be preying on ants or beetles, or hiding in a crowd, as well as mimicking distasteful models. Also, while few or no salticid (jumping) spiders inhabit ant nests, there are ant mimicking spiders that do so and these thus are Wasmannian mimics."

Gilbertian - from Wikipedia(1) - "Unlike the above forms of mimicry, Gilbertian mimicry involves only two species. The potential host/prey drives away its parasite/predator by mimicking it, the reverse of host-parasite aggressive mimicry. It was coined by Pasteur as a term for such rare mimicry systems, and is named after the American ecologist Lawrence E. Gilbert.

This form of protective mimicry occurs in the genus Passiflora. The leaves of this plant contain toxins which deter herbivorous animals, however some Heliconius butterfly larvae have evolved enzymes which break down these toxins, allowing them to specialize on this genus. This has created further selection pressure on the host plants, which have evolved stipules that mimic mature Heliconius eggs near the point of hatching. These butterflies tend to avoid laying eggs near each existing ones, which helps avoid exploitative intraspecific competition between caterpillars—those that lay on vacant leaves provide their offspring with a greater chance of survival. Additionally, most Heliconius larvae are cannibalistic, meaning those leaves with older eggs will hatch first and eat the new arrivals. Thus, it seems such plants have evolved egg dummies due to these grazing herbivore enemies. The decoy eggs are also nectaries though, attracting predators of the caterpillars such as ants and wasps. The extent of their mimetic function is therefore slightly more difficult to assess.

The use of eggs is not essential to this system, only the species composition and protective function. Many other forms of mimicry also involve eggs, such as cuckoo eggs mimicking those of their host (the reverse of this situation), or plants seeds (often those with an elaiosome) being dispersed by ants, who treat them as they would their own eggs."

  from book excerpt from "Animal behavior desk reference: a dictionary of animal behavior, ecology" By Edward M. Barrows(8) - "n. Protective mimicry in which the model and the dupe are conspecific (e.g., Passiflora stipules that mimic Heliconius butterfly eggs near the point of hatching) (Gilbert 1975 in Pasteur 1982, 186).
syn. egg mimicry (Gilbert 1983, 278; Sbordoni and Forestiero 1985, 191) Comment: Because larvae of most Heliconius females avoid ovipositing on plants bearing such eggs (Pasteur 1982, 186) [after L.E Gilbert, biologist, who discovered this phenomenon]"


Browerian - from Wikipedia(1) - "Browerian mimicry, named after Lincoln P. Brower and Jane Van Zandt Brower, is a form of automimicry; where the model belongs to the same species as the mimic. This is the analogue of Batesian mimicry within a single species, and occurs when there is a palatability spectrum within a population. One example is Monarch Butterflies (Danaus plexippus), which feed on milkweed species of varying toxicity. This species stores toxins from its host plant, which are maintained even in the adult form. As the levels of toxin will vary depending on diet during the larval stage, some individuals will be more toxic than others. The less palatable organisms will therefore be mimics of the more dangerous individuals, with their likeness already perfected. This need not be the case however; in sexually dimorphic species one sex may be more of a threat than the other, which could mimic the protected sex. Evidence for this possibility is provided by the behavior of a monkey from Gabon, which regularly ate male moths of the genus Anaphe, but promptly stopped after it tasted a noxious female."

  from International Journal of Zoology(9) - "When individuals within a species differ in palatability to predators, the more palatable individuals (mimics) will gain benefits from those less palatable (models). The models can be of the same or opposite sex to the mimics. Albeit never reported that this type of mimicry may be present in aromobatids, bufonids, dendrobatids, mantellids, and myobatrachids, at least. Individuals of the same noxious species of these families acquire the alkaloids contained in their noxious secretions from dietary arthropods. Therefore, if for any reason a group of individuals within a species either does not feed on arthropods that carry the alkaloids, feeds on them but at a lower rate/proportion, or does not sequester these components, they will be less poisonous than the others. Indeed, there are reports that show spatial (geographic) and temporal (seasonal) variation in the alkaloid profiles of poison frogs , which may support the Browerian mimicry theory for anurans."
  

Aggressive - from Wikipedia(1) - "Aggressive mimicry describes predators (or parasites) which share the same characteristics as a harmless species, allowing them to avoid detection by their prey (or host). It is less often known as Peckhamian mimicry after George and Elizabeth Peckham. The mimic may resemble the prey or host itself, or another organism which is either neutral or beneficial to the signal receiver. In this class of mimicry the model may be affected negatively, positively or not at all. Just as parasites can be treated as a form of predator, host-parasite mimicry is treated here as a subclass of aggressive mimicry.

The mimic may have a particular significance for duped prey. One such case is spiders, amongst which aggressive mimicry is quite common in both in luring prey and stealthily approaching predators. One case is the Golden Orb Weaver (Nephila clavipes), which spins a conspicuous golden colored web in well-lit areas. Experiments show that bees are able to associate the webs with danger when the yellow pigment is not present, as occurs in less well-lit areas where the web is much harder to see. Other colors were also learned and avoided, but bees seemed least able to effectively associate yellow pigmented webs with danger. Yellow is the color of many nectar bearing flowers, however, so perhaps avoiding yellow is not worth while. Another form of mimicry is based not on color but pattern. Species such as Argiope argentata employ prominent patterns in the middle of their webs, such as zigzags. These may reflect ultraviolet light, and mimic the pattern seen in many flowers known as nectar guides. Spiders change their web day to day, which can be explained by bee's ability to remember web patterns. Bees are able to associate a certain pattern with a spatial location, meaning the spider must spin a new pattern regularly or suffer diminishing prey capture.

Another case is where males are lured towards what would seem to be a sexually receptive female; the model in this situation being the same species as the dupe. Beginning in the 1960s, James E. Lloyd's investigation of female fireflies of the genus Photuris revealed they emit the same light signals that females of the genus Photinus use as a mating signal. Further research showed male fireflies from several different genera are attracted to these "femmes fatales", and are subsequently captured and eaten. Female signals are based on that received from the male, each female having a repertoire of signals matching the delay and duration of the female of the corresponding species. This mimicry may have evolved from non-mating signals that have become modified for predation.

The listrosceline katydid Chlorobalius leucoviridis of inland Australia is capable of attracting male cicadas of the Tribe Cicadettini by imitating the species-specific reply clicks of sexually receptive female cicadas. This example of acoustic aggressive mimicry is similar to the Photuris firefly case in that the predator’s mimicry is remarkably versatile – playback experiments show that C. leucoviridis is able to attract males of many cicada species, including Cicadettine cicadas from other continents, even though cicada mating signals are species-specific.
Luring is not a necessary condition however, as the predator will still have a significant advantage by simply not being identified as such. They may resemble a mutualistic symbiont or a species of little relevance to the prey.

A case of the former situation is a species of cleaner fish and its mimic, though in this example the model is greatly disadvantaged by the presence of the mimic. Cleaner fish are the allies of many other species, which allow them to eat their parasites and dead skin. Some allow the cleaner to venture inside their body to hunt these parasites. However, one species of cleaner, the Bluestreak cleaner wrasse (Labroides dimidiatus), is the unknowing model of a mimetic species, the Sabre-toothed blenny (Aspidontus taeniatus). This wrasse, shown to the left cleaning a grouper of the genus Epinephelus, resides in coral reefs in the Indian and the Pacific Oceans, and is recognized by other fishes who then allow it to clean them. Its imposter, a species of blenny, lives in the Indian Ocean and not only looks like it in terms of size and coloration, but even mimics the cleaner's 'dance'. Having fooled its prey into letting its guard down, it then bites it, tearing off a piece of its fin before fleeing the scene. Fish grazed upon in this fashion soon learn to distinguish mimic from model, but because the similarity is close between the two they become much more cautious of the model as well, such that both are affected. Due to victim's ability to discriminate between foe and helper, the blennies have evolved close similarity, right down to the regional level.

Another interesting example that does not involve any luring is the Zone-tailed Hawk, which resembles the Turkey Vulture. It flies amongst the vultures, suddenly breaking from the formation and ambushing its prey. Here the hawk's presence is of no evident significance to the vultures, affecting them neither negatively or positively.

Parasites can also be aggressive mimics, though the situation is somewhat different from those outlined above. Some of the predators described have a feature that draws prey, and parasites can also mimic their host's natural prey, but are eaten themselves, a pathway into their host. Leucochloridium, a genus of flatworm, matures in the digestive system of songbirds, their eggs then passing out of the bird via the feces . They are then taken up by Succinea, a terrestrial snail. The eggs develop in this intermediate host, and then must find of a suitable bird to mature in. Host birds do not eat snails though, so the sporocyst must find some strategy to reach its host's intestine. For this function, they are brightly colored and move in a pulsating fashion. A sporocyst-sac pulsates in the snail's eye stalks, coming to resemble an irresistible meal for a songbird. In this way, it can bridge the gap between hosts, allowing it to complete its life cycle. A nematode (Myrmeconema) changes the colour of the abdomen of workers of the canopy ant Cephalotes atratus to make it appear like the ripe fruits of Hyeronima alchorneoides. It also changes the behaviour of the ant so that the gaster is held raised and this possibly increases the chances of the ant being eaten by birds. The droppings of birds are collected by other ants and fed to their brood, thereby helping to spread the nematode.

In an unusual case, planidium larvae of some beetles of the genus Meloe will form a group and produce a pheromone that mimics the sex attractant of its host bee species; when the male bee arrives and attempts to mate with the mass of larvae, they climb onto his abdomen, and from there transfer to a female bee, and from there to the bee nest to parasitize the bee larvae.

Host-parasite mimicry is a two species system where a parasite mimics its own host. Cuckoos are a canonical example of brood parasitism, a form of kleptoparasitism where the mother has its offspring raised by another unwitting organism, cutting down the biological mother's parental investment in the process. Cases of intraspecific brood parasitism, where a female lays in conspecific's nest do not represent a case of mimicry."

  from Britannica Online - Aggressive mimicry(10) - "a form of similarity in which a predator or parasite gains an advantage by its resemblance to a third party. This model may be the prey (or host) species itself, or it may be a species that the prey does not regard as threatening. An example in which the prey itself serves as the model can be seen in the mimicry used by female fireflies of the genus Photuris. These insects imitate the mating flashes of the fireflies of the genus Photinus; the unlucky Photinus males deceived by the mimics are eaten. Another example is found in the brood parasitism practiced by the European cuckoo (Cuculus canorus). The eggs of this species closely resemble those of several kinds of small birds, in whose nests the cuckoo lays its clutch. The hosts accept the eggs as their own and hatch and rear the young cuckoos.

Aggressive mimicry in which the predator resembles a nonthreatening third party is exemplified by the American zone-tailed hawk, whose resemblance to certain nonaggressive vultures enables it to launch surprise attacks against small animals. In other examples, the aggressor may even mimic the prey of its intended prey. Anglerfish, for example, possess a small, mobile, wormlike organ that can be waved on a slender rod in front of other fish; lured in by this organ, which they mistake for their own natural prey, smaller fish are eaten by the anglerfish. In these cases, similar characteristics evolve independently in different lineages, thus reflecting a form of convergent evolution."
   

Bakerian - from Wikipedia(1) - "Bakerian mimicry, named after Herbert G. Baker, is a form of automimicry where female flowers mimic male flowers of their own species, cheating pollinators out of a reward. This reproductive mimicry may not be readily apparent as members of the same species may still exhibit some degree of sexual dimorphism. It is common in many species of Caricaceae.

Like Bakerian mimicry, Dodsonian mimicry is a form of reproductive floral mimicry, but the model belongs to a different species than the mimic. The name refers to Calaway H. Dodson. By providing similar sensory signals as the model flower, it can lure its pollinators. Like Bakerian mimics, no nectar is provided. Epidendrum ibaguense of the family Orchidaceae resembles flowers of Lantana camara and Asclepias curassavica, and is pollinated by Monarch Butterflies and perhaps hummingbirds. Similar cases are seen in some other species of the same family. The mimetic species may still have pollinators of its own though, for example a lamellicorn beetle which usually pollinates correspondingly colored Cistus flowers is also known to aid in pollination of Ophrys species that are normally pollinated by bees."

Pseudocopulation - from Wikipedia(1) - "Pseudocopulation occurs when a flower mimics a female of a certain insect species, the males of which try to copulate with it. This is much like the aggressive mimicry in fireflies described above, but with a much more benign outcome for the pollinator. This form of mimicry has been called Pouyannian mimicry, after Pouyanne, who first described the phenomenon. It is most common in orchids which mimic females of the order Hymenoptera (generally bees and wasps), and may account for around 60% of pollinations. Depending on the morphology of the flower, a pollen sac called a pollinia is attached to the head or abdomen of the male. This is then transferred to the stigma of the next flower the male tries to inseminate, resulting in pollination. Visual mimicry is the most obvious sign of this deception for humans, but the visual aspect may be minor or non-existent. It is the senses of touch and olfaction that are most important."

  from Oxford Journals - Sexual Mimicry in Mormolyca ringens(11) - "Background and Aims - Pollination through sexual mimicry, also known as pseudocopulation, has been suggested to occur in some genera of the Neotropical orchid subtribe Maxillariinae. However, it has been demonstrated so far only for Trigonidium obtusum. This study reports and illustrates pollination through sexual mimicry in Mormolyca ringens.
Methods - A total of 70 h were dedicated to the observation of flowers and pollinator behaviour, which was photographically recorded. Flower features involved in pollinator attraction were studied using a stereomicroscope and by SEM analyses. Preliminary observations on the plant breeding system were made by manually self-pollinating flowers. The chemical composition of the fragrance volatiles was determined by GC/MS analysis.

Key Results - The flower features of M. ringens parallel those of other pseudocopulatory flowers. The labellum shape and indument are reminiscent of an insect. Sexually excited drones of Nannotrigona testaceicornis and Scaptotrigona sp. (both in the Apidae: Meliponini) attempt copulation with the labellum and pollinate the flower in the process. In both bee species, the pollinarium is attached to the scutellum. Pollinator behaviour may promote some degree of self-pollination, but preliminary observations indicate that M. ringens flowers are self-incompatible. Flowers are produced all the year round, which ties in with the production of bee males several times a year. The phylogenetic relationships of M. ringens are discussed and a number of morphological and phenological features supporting them are reported.

Conclusions - It is expected that further research could bring to light whether other Maxillariinae species are also pollinated through sexual mimicry. When a definitive and robust phylogeny of this subtribe is available, it should be possible to determine how many times pseudocopulation evolved and its possible evolutionary history."

Automimicry - from Wikipedia(1) - "Automimicry or intraspecific mimicry occurs within a single species, one case being where one part of an organism's body resembles another part. Examples include snakes in which the tail resembles the head and show behavior such as moving backwards to confuse predators and insects and fishes with eye spots on their hind ends to resemble the head. The term is also used when the mimic imitates other morphs within the same species. When males mimic females or vice versa this may be referred to as sexual mimicry."

  from Paper: Automimicry destabilizes aposematism(12) - "Aposematism, the use of conspicuous colours to advertise unpalatability to predators, is perhaps the most studied signaling system in nature. However, its evolutionary stability remains paradoxical. The paradox is illustrated by the problem of automimicry. Automimics are palatable individuals within a population of unpalatable aposematics. Automimics benefit from predators avoiding warning coloration without carrying the models' cost of unpalatability, and should increase in the population, destabilizing the signaling system, unless selected against in some way. Cautious sampling, instead of avoidance, by predators may offer a solution to this problem. Here, we investigate the effect of automimic frequency on predator sampling behaviour, and whether predator sampling behavior may provide a selection pressure against mimics. Domestic chicks (Gallus gallus domesticus) were subjected to the task of discriminating between green (signaling) and untreated brown chick crumbs. Some of the green crumbs were quinine treated and thus unpalatable. The frequency of palatable signaling prey items varied in four treatments; all unpalatable, low automimic frequency, high automimic frequency and all palatable. The results show that predator sampling behavior is sensitive to automimic frequency and that predators may discriminate between models and mimics through sampling, and thereby benefit unprofitable prey. The results suggest somewhat surprisingly that aposematic signaling is stable only because of the actions of those predators not actually deterred by warning signals."


Ok, enuff book learnin'  :-O

Shown below are mimics and, when possible, what they are mimicking.
Please note however, that I am not at all implying that the mimics shown are all that exist nor am I implying that they are mimicking any particular species. The images of mimics and models shown below just happen to resemble each other and are simply convenient for this article to illustrate mimicry, but one particular species of mimic is not necessarily mimicking any one particular species of model.

CRITTERS MIMICKING ANTS

..........spiders

   ..........and actual ants-   

--------> Interesting Facts -
  It has been noted that some ant mimics live among ant colonies to prevent predation but also to prey on other spider eggs and juveniles. Studies have shown that spiders typically fear ants because ants can cause a lot of damage to a comparatively fragile spider. It has also been shown that other salticids, in particular, will move away, and even turn and run in some cases, when near an ant such as Crematogaster (Acrobat Ants). Therefore salticids such as Myrmarachne profit from this by driving away other adult salticids just by coming near them and then eating their eggs or young.

There is also an interesting article regarding Myrmarachne melanotarsa called The natural history of Myrmarachne melanotarsa, a social ant-mimicking jumping spider (click link to open PDF) from the New Zealand Journal Of Zoology, 2008. It goes into a lot of detail regarding ant-mimicking behavior, primarily with regard to jumping spiders. A couple of facts I read in this article I found very interesting. One says "Ants appear to be particularly suitable as models for Batesian mimics because, besides being especially abundant insects in most terrestrial habitats, they are notorious for their defensive adaptations, including powerful mandibles, poison-injecting stings, and ability as social insects to mount communal attacks." In other words, this is saying that due to ants having excellent defenses, it is a great benefit to mimic them to avoid predation. However, in an article from "The Journal of Arachnology" entitled "Living With The Enemy: Jumping Spiders That Mimic Weaver Ants" it was noted that "Batesian mimics of ants may be forced to 'walk a tightrope', needing to 'live with the enemy'. They need to be close to the model for safety from other predators but at the same time they need to avoid becoming the model's prey." In this article they also did testing of their own. They tested on what they called 'four categories of salticids'. They were "myrmecophagic species - species that select ants as preferred prey, myrmecomorphic species - species that resemble ants, myrmecophilic species - a salticid species that is neither myrmecophagic nor myrmecomorphic, but known to associate with ants, and finally ordinary species". They also state, similar to the previous article, that "Exceptional eyesight may enable salticids to be especially effective at detecting ants from a distance and avoiding dangerous proximity, but the strategies of myrmecophilic, myrmecomorphic and myrmecophagic salticids cannot be simply to avoid ants. For example, myrmecophagic salticids must at least intermittently come close enough to attack individual ants." They also point out that "Ants rely primarily on chemical, not visual, information for detecting other ants(Hölldobler & Wilson 1990). Many ants use cuticular hydrocarbons to distinguish between nestmates and non-nestmates (Hölldobler & Wilson 1990; Thomas et al. 1999; Wagner et al. 2000). The salticid spider Cosmophasis bitaeniata (Keyserling 1882) associates with O. smaragdina and is an exploitative chemical mimic of its host." So, this is indicative of yet another form of mimicry by using chemical cues to mimic it's model.



..........bugs

   ..........and actual ants-   


                                                                                                                                                                                                                                       

References

also see BugGuide articles :
Lycid mimicry complex in eastern North America
Moths That Can Be Confused
Similar Looking Spiders in Different Families

Wikipedia

Charles Darwin

Britannica Online - Müllerian mimicry

wiseGEEK

web article on Henry Walter Bates

Distance Learning article

The Conservation Report

Microscopy-UK - ANTS, BEETLES AND SPIDERS by David B. Richman

book excerpt from "Animal behavior desk reference: a dictionary of animal behavior, ecology" By Edward M. Barrows

in the Directory Of Open Access Journals - International Journal of Zoology
Volume 2009 (2009), Article ID 910892


Britannica Online - Aggressive mimicry

Oxford Journals - Sexual Mimicry in Mormolyca ringens (Lindl.) Schltr. (Orchidaceae: Maxillariinae)
RODRIGO B. SINGER, ADRIANA FLACH, SAMANTHA KOEHLER, ANITA J. MARSAIOLI, and MARIA DO CARMO E. AMARAL


sci.tech-archive.net - Paper: Automimicry destabilizes aposematism: predator sample-and-reject behaviour may provide a solution
From: Robert Karl Stonjek - Aggressive mimicry


                                                                                                                                                                                                                                       

Suggestion
Line breaks between paragraphs would make this easier to read--in particular in that long "Aggressive" section.

 
Hey Charley....
Thanks for the help. How does it look now?

 
Much easier on the eyes
Thanks! By the way, I just remembered a neat example of mimicry I stumbled on a few months ago. I don't know if it has a place in your article, but I thought you'd be interested. Here it is (quoted from Bob Carlson, here):

"I wonder what Darwin might have said about the false cocoons that are spun by a few species [of] Ichneumonidae of the genus Hyposoter. These species spin their real cocoons inside the skins of hairy caterpillars, and the cocoon keeps the skin of the caterpillar firmly inflated. On the outside of the skin, the Hyposoter larva spins a small false cocoon that is quite similar in appearance to the cocoons of braconid wasps of the genus Cotesia. The false cocoon is left open at one end, and resembles a Cotesia cocoon from which the Cotesia adult has already emerged. The empty false cocoon is presumed to be a mechanism that helps to protect the Hyposoter individual in the real cocoon from being attacked by hyperparasitic wasps."

Mimic questions
Sam, did your article prep turn up any information on Rainieria antennaepes one of the Stilt-legged flies? Kaufman (P 312)(1) suggests that it is a wasp mimic waving it front legs (usually with white patches) around like (I assume) Ichneumon wasp antennae. If so, this is perhaps a Batesian mimic although the what and why are not at all clear. Most that I have observed wave their forelegs around in a sensory-seeking manner unlike that of the wasps (which are also sensory of some sort but which move quite differently if viewed closely). The subtlety of some of the human categorized varieties of mimics alludes me. If this is an Ichneumon mimic is it trying to be scary or alluring to something which might like or dislike wasps? If not a Batesian mimic is it some other kind of mimicry or just a coincidental similarity (why DO Ichneumons (and a few sawflys and others) have those white patches on their antennae anyway?)

 
Ichneumons
In the course of writing (much of) the Kaufman guide I learned that some ichneumon wasps do in fact sting, so mimicking one of the stinging varieties is not a bad prospect. I don't see anything "subtle" about most mimicry. It is quite graphic to my eye, especially if the insect is behaving like its model.

 
This one
kind of stung me (or at least tried to). I also thought they didn't sting, but it made a go of it.


I love the way the jumping spiders I have seen walk around on 6 legs waving 2 legs in the air (do they care?) like antennae to complete the illusion.

 
Mimicry or similarity?
Interesting... I was last week watching (without a camera) a southern Georgia relative of my local (KY) Rainieria (this one was muted brown without the red eyes (roughly a 1 cm bug) - perhaps one of the ant mimics (Looked much like) which from two meters away still (using your "quite graphic to my eye" criteria) was neither wasp nor ant, based on its behavior. I did not mean to dispute similarity (visual and/or behavioral) but rather was suggesting that similarity itself should not automatically lead to assumed mimicry without detailed consideration of the specific traits mimicked.

 
Roy,
To answer your initial question, no I have not yet came across info on ichneumons or wasp mimics. However, I am nowhere near finished with the article so I'm sure I will. Please check back periodically as new info is added.

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