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76-678: Caterpillars ( / ˈ k æ t ər p ɪ l ər / KAT -ər-pil-ər ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths ). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Symphyta) are commonly called caterpillars as well. Both lepidopteran and symphytan larvae have eruciform body shapes. Caterpillars of most species eat plant material ( often leaves ), but not all; some (about 1%) eat insects , and some are even cannibalistic. Some feed on other animal products. For example, clothes moths feed on wool, and horn moths feed on

152-548: A pupal stage before becoming adults. Caterpillars grow very quickly; for instance, a tobacco hornworm will increase its weight ten-thousandfold in less than twenty days. An adaptation that enables them to eat so much is a mechanism in a specialized midgut that quickly transports ions to the lumen (midgut cavity), to keep the potassium level higher in the midgut cavity than in the hemolymph . Most caterpillars are solely herbivorous . Many are restricted to feeding on one species of plant, while others are polyphagous. Some, including

228-484: A caterpillar with an aggressive defense mechanism will learn and avoid future attempts. Some caterpillars regurgitate acidic digestive juices at attacking enemies. Many papilionid larvae produce bad smells from extrudable glands called osmeteria . Many caterpillars display feeding behaviors which allow the caterpillar to remain hidden from potential predators. Many feed in protected environments, such as enclosed inside silk galleries, rolled leaves or by mining between

304-583: A distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles , adults are immobile but their larvae are mobile, and use their mobile larval form to distribute themselves. These larvae used for dispersal are either planktotrophic (feeding) or lecithotrophic (non-feeding) . Some larvae are dependent on adults to feed them. In many eusocial Hymenoptera species,

380-467: A dormant state. The appearance of a caterpillar can often repel a predator: its markings and certain body parts can make it seem poisonous, or bigger in size and thus threatening, or non-edible. Some types of caterpillars are indeed poisonous or distasteful and their bright coloring warns predators of this . Others may mimic dangerous caterpillars or other animals while not being dangerous themselves. Many caterpillars are cryptically colored and resemble

456-509: A drug-induced dream, while in labor, that she captures a caterpillar and holds it firmly in her hand. In The Sopranos season 5 episode " The Test Dream ", Tony Soprano dreams that Ralph Cifaretto has a caterpillar on his bald head that changes into a butterfly. Click left or right for a slide show. Larva A larva's appearance is generally very different from the adult form ( e.g. caterpillars and butterflies ) including different unique structures and organs that do not occur in

532-505: A function of water depth. For example, the Spanish Dancer nudibranch (genus Hexabranchus ), among the largest of tropical marine slugs, potently chemically defended, and brilliantly red and white, is nocturnal and has no known mimics. Mimicry is to be expected as Batesian mimics with weak defences can gain a measure of protection from their resemblance to aposematic species. Other studies have concluded that nudibranchs such as

608-610: A letter to Alfred Russel Wallace dated 23 February 1867, Charles Darwin wrote, "On Monday evening I called on Bates & put a difficulty before him, which he could not answer, & as on some former similar occasion, his first suggestion was, 'you had better ask Wallace'. My difficulty is, why are caterpillars sometimes so beautifully & artistically coloured?" Darwin was puzzled because his theory of sexual selection (where females choose their mates based on how attractive they are) could not apply to caterpillars since they are immature and hence not sexually active. Wallace replied

684-442: A predator from a distance, but are warning-like from a close proximity, allowing for an advantageous balance between camouflage and aposematism. Warning coloration evolves in response to background, light conditions, and predator vision. Visible signals may be accompanied by odors, sounds or behavior to provide a multi-modal signal which is more effectively detected by predators. Unpalatability, broadly understood, can be created in

760-546: A predator long enough to enable an otherwise undefended prey to escape. The term aposematism was coined by the English zoologist Edward Bagnall Poulton in his 1890 book The Colours of Animals . He based the term on the Ancient Greek words ἀπό apo 'away' and σῆμα sēma 'sign', referring to signs that warn other animals away. The function of aposematism is to prevent attack, by warning potential predators that

836-725: A variety of ways. Some insects such as the ladybird or tiger moth contain bitter-tasting chemicals, while the skunk produces a noxious odor, and the poison glands of the poison dart frog , the sting of a velvet ant or neurotoxin in a black widow spider make them dangerous or painful to attack. Tiger moths advertise their unpalatability by either producing ultrasonic noises which warn bats to avoid them, or by warning postures which expose brightly coloured body parts (see Unkenreflex ), or exposing eyespots . Velvet ants (actually parasitic wasps) such as Dasymutilla occidentalis both have bright colors and produce audible noises when grabbed (via stridulation ), which serve to reinforce

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912-432: Is a sufficiently successful strategy to have had significant effects on the evolution of both aposematic and non-aposematic species. Non-aposematic species have often evolved to mimic the conspicuous markings of their aposematic counterparts. For example, the hornet moth is a deceptive mimic of the yellowjacket wasp; it resembles the wasp, but has no sting. A predator which avoids the wasp will to some degree also avoid

988-609: Is among the most potent defensive chemicals in any animal is produced by the South American silk moth genus Lonomia . Its venom is an anticoagulant powerful enough to cause a human to hemorrhage to death (See Lonomiasis ). This chemical is being investigated for potential medical applications. Most urticating hairs range in effect from mild irritation to dermatitis . Example: brown-tail moth . Plants contain toxins which protect them from herbivores, but some caterpillars have evolved countermeasures which enable them to eat

1064-568: Is another approach used in reducing the impact of caterpillars on crop plants. Some caterpillars are used in industry. The silk industry is based on the silkworm caterpillar. Caterpillar hair can be a cause of human health problems. Caterpillar hairs sometimes have venoms in them and species from approximately 12 families of moths or butterflies worldwide can inflict serious human injuries ranging from urticarial dermatitis and atopic asthma to osteochondritis , consumption coagulopathy , kidney failure , and brain bleeding . Skin rashes are

1140-520: Is argued to be sufficient for such species to be considered aposematic. It has been proposed that aposematism and mimicry is less evident in marine invertebrates than terrestrial insects because predation is a more intense selective force for many insects, which disperse as adults rather than as larvae and have much shorter generation times. Further, there is evidence that fish predators such as blueheads may adapt to visual cues more rapidly than do birds, making aposematism less effective. However, there

1216-501: Is based on Antonio Berlese classification in 1913. There are four main types of endopterygote larvae types: Aposematism Aposematism is the advertising by an animal, whether terrestrial or marine, to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the prey difficult to kill and eat, such as toxicity, venom , foul taste or smell, sharp spines, or aggressive nature. These advertising signals may take

1292-469: Is experimental evidence that pink warty sea cucumbers are aposematic, and that the chromatic and achromatic signals that they provide to predators both independently reduce the rate of attack. Blue-ringed octopuses are venomous. They spend much of their time hiding in crevices whilst displaying effective camouflage patterns with their dermal chromatophore cells. However, if they are provoked, they quickly change colour, becoming bright yellow with each of

1368-399: Is no statistical relationship between the two factors. Nudibranch molluscs are the most commonly cited examples of aposematism in marine ecosystems, but the evidence for this has been contested, mostly because (1) there are few examples of mimicry among species, (2) many species are nocturnal or cryptic, and (3) bright colours at the red end of the colour spectrum are rapidly attenuated as

1444-412: Is one species that preys upon caterpillars. The flycatcher typically finds caterpillars among oak foliage. Paper wasps , including those in the genus Polistes and Polybia catch caterpillars to feed their young and themselves. Caterpillars have been called "eating machines", and eat leaves voraciously. Most species shed their skin four or five times as their bodies grow, and they eventually enter

1520-430: Is selected by predators. Concurrent reciprocal selection (CRS) may entail learning by predators or it may give rise to unlearned avoidances by them. Aposematism arising by CRS operates without special conditions of the gregariousness or the relatedness of prey, and it is not contingent upon predator sampling of prey to learn that aposematic cues are associated with unpalatability or other unprofitable features. Aposematism

1596-787: Is significant. The sound-producing rattle of rattlesnakes is an acoustic form of aposematism. Sound production by the caterpillar of the Polyphemus moth, Antheraea polyphemus , may similarly be acoustic aposematism, connected to and preceded by chemical defences. Similar acoustic defences exist in a range of Bombycoidea caterpillars. The existence of aposematism in marine ecosystems has been debated. Many marine organisms, particularly those on coral reefs, are brightly coloured or patterned, including sponges, corals, molluscs, and fish, with little or no connection to chemical or physical defenses. Caribbean reef sponges are brightly coloured, and many species are full of toxic chemicals, but there

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1672-441: Is strong enough to allow seemingly maladaptive traits to persist despite other factors working against the trait. Once aposematic individuals reach a certain threshold population, for whatever reason, the predator learning process would be spread out over a larger number of individuals and therefore is less likely to wipe out the trait for warning coloration completely. If the population of aposematic individuals all originated from

1748-557: The X chromosome . If so, predators would learn to associate the colour with unpalatability from males with the trait, while heterozygous females carry the trait until it becomes common and predators understand the signal. Well-fed predators might also ignore aposematic morphs, preferring other prey species. A further explanation is that females might prefer brighter males, so sexual selection could result in aposematic males having higher reproductive success than non-aposematic males if they can survive long enough to mate. Sexual selection

1824-418: The clothes moth , feed on detritus . Some are predatory, and may prey on other species of caterpillars (e.g. Hawaiian Eupithecia ). Others feed on eggs of other insects, aphids, scale insects, or ant larvae. A few are parasitic on cicadas or leaf hoppers ( Epipyropidae ). Some Hawaiian caterpillars ( Hyposmocoma molluscivora ) use silk traps to capture snails. Many caterpillars are nocturnal. For example,

1900-623: The locust , thus they are one of the plagues of Egypt. Jeremiah names them as one of the inhabitants of Babylon . The English word caterpillar derives from the old French catepelose (hairy cat) but merged with the piller (pillager). Caterpillars became a symbol for social dependents. Shakespeare 's Bolingbroke described King Richard 's friends as "The caterpillars of the commonwealth, Which I have sworn to weed and pluck away". In 1790 William Blake referenced this popular image in The Marriage of Heaven and Hell when he attacked priests: "as

1976-451: The "cutworms" (of the family Noctuidae ) hide at the base of plants during the day and only feed at night. Others, such as spongy moth ( Lymantria dispar ) larvae, change their activity patterns depending on density and larval stage, with more diurnal feeding in early instars and high densities. Caterpillars cause much damage, mainly by eating leaves. The propensity for damage is enhanced by monocultural farming practices, especially where

2052-449: The 50-60 rings flashing bright iridescent blue within a third of a second. It is often stated this is an aposematic warning display, but the hypothesis has rarely if ever been tested. The mechanism of defence relies on the memory of the would-be predator; a bird that has once experienced a foul-tasting grasshopper will endeavor to avoid a repetition of the experience. As a consequence, aposematic species are often gregarious. Before

2128-489: The Christian tradition. Goedart thus located his empirical observations on the transformation of caterpillars into butterflies in the Christian tradition. As such he argued that the metamorphosis from caterpillar into butterfly was a symbol, and even proof, of Christ's resurrection. He argued "that from dead caterpillars emerge living animals; so it is equally true and miraculous, that our dead and rotten corpses will rise from

2204-401: The adult form. Their diet may also be considerably different. In the case of smaller primitive arachnids, the larval stage differs by having three instead of four pairs of legs. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs . By living in

2280-658: The brighter and more conspicuous the organism, the more toxic it usually is. This is in contrast to deimatic displays , which attempt to startle a predator with a threatening appearance but which are bluffing, unsupported by any strong defences. The most common and effective colors are red, yellow, black, and white. These colors provide strong contrast with green foliage, resist changes in shadow and lighting, are highly chromatic, and provide distance dependent camouflage . Some forms of warning coloration provide this distance dependent camouflage by having an effective pattern and color combination that do not allow for easy detection by

2356-533: The brown & green eatable catterpillars, would enable birds to recognise them easily as at a kind not fit for food, & thus they would escape seizure which is as bad as being eaten ." Since Darwin was enthusiastic about the idea, Wallace asked the Entomological Society of London to test the hypothesis. In response, the entomologist John Jenner Weir conducted experiments with caterpillars and birds in his aviary, and in 1869 he provided

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2432-551: The caterpillar chooses the fairest leaves to lay her eggs on, so the priest lay his curse on the fairest joys". The role of caterpillars in the life stages of butterflies was badly understood. In 1679 Maria Sibylla Merian published the first volume of The Caterpillars' Marvelous Transformation and Strange Floral Food , which contained 50 illustrations and a description of insects, moths, butterflies and their larvae . An earlier popular publication on moths and butterflies, and their caterpillars, by Jan Goedart had not included eggs in

2508-428: The caterpillar is specifically adapted to the host plant under cultivation. The cotton bollworm causes enormous losses. Other species eat food crops. Caterpillars have been the target of pest control through the use of pesticides , biological control and agronomic practices. Many species have become resistant to pesticides . Bacterial toxins such as those from Bacillus thuringiensis which are evolved to affect

2584-464: The caterpillars of the Lepidoptera. Such larvae are mainly seen in the sawfly suborder. However while these larvae superficially resemble caterpillars, they can be distinguished by the presence of prolegs on every abdominal segment, an absence of crochets or hooks on the prolegs (these are present on lepidopteran caterpillars), one pair of prominent ocelli on the head capsule, and an absence of

2660-440: The concept aposematism in his book The Colours of Animals . He described the derivation of the term as follows: The second head (Sematic Colours) includes Warning Colours and Recognition Markings: the former warn an enemy off, and are therefore called Aposematic [Greek, apo , from, and sema , sign] Aposematism is paradoxical in evolutionary terms, as it makes individuals conspicuous to predators, so they may be killed and

2736-533: The digression of those who have tried to prove Resurrection of the Dead from these obviously natural and comprehensible changes within the creature itself." Since then the metamorphoses of the caterpillar into a butterfly has in Western societies been associated with countless human transformations in folktales and literature. There is no process in the physical life of human beings that resembles this metamorphoses, and

2812-472: The environment such as bird droppings. Some Geometridae cover themselves in plant parts, while bagworms construct and live in a bag covered in sand, pebbles or plant material. More aggressive self-defense measures have evolved in some caterpillars. These measures include having spiny bristles or long fine hair-like setae with detachable tips that will irritate by lodging in the skin or mucous membranes. However some birds (such as cuckoos ) will swallow even

2888-406: The eyes. Once they enter such tissues, they can be difficult to extract, often exacerbating the problem as they migrate across the membrane. This becomes a particular problem in an indoor setting. The hair easily enter buildings through ventilation systems and accumulate in indoor environments because of their small size, which makes it difficult for them to be vented out. This accumulation increases

2964-417: The first experimental evidence for warning coloration in animals. The evolution of aposematism surprised 19th-century naturalists because the probability of its establishment in a population was presumed to be low, since a conspicuous signal suggested a higher chance of predation. Wallace coined the term "warning colours" in an article about animal coloration in 1877. In 1890 Edward Bagnall Poulton renamed

3040-530: The form of conspicuous coloration , sounds , odours , or other perceivable characteristics. Aposematic signals are beneficial for both predator and prey, since both avoid potential harm. The term was coined in 1877 by Edward Bagnall Poulton for Alfred Russel Wallace 's concept of warning coloration . Aposematism is exploited in Müllerian mimicry , where species with strong defences evolve to resemble one another. By mimicking similarly coloured species,

3116-483: The founder of Cartesian philosophy, and his theory on innate ideas. Descartes argued that we are distracted by urgent bodily stimuli that swamp the human mind in childhood. Descartes also theorised that inherited preconceived opinions obstruct the human perception of the truth . More recent symbolic references to caterpillars in popular media include the Mad Men season 3 episode "The Fog", in which Betty Draper has

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3192-401: The grave." Swammerdam, who in 1669 had demonstrated that inside a caterpillar the rudiments of the future butterfly's limbs and wings could be discerned, attacked the mystical and religious notion that the caterpillar died and the butterfly subsequently resurrected. As a militant Cartesian , Swammerdam attacked Goedart as ridiculous, and when publishing his findings he proclaimed "here we witness

3268-473: The gut of Lepidoptera have been used in sprays of bacterial spores, toxin extracts and also by incorporating genes to produce them within the host plants. These approaches are defeated over time by the evolution of resistance mechanisms in the insects. Plants evolve mechanisms of resistance to being eaten by caterpillars, including the evolution of chemical toxins and physical barriers such as hairs. Incorporating host plant resistance (HPR) through plant breeding

3344-424: The hairiest of caterpillars. Other caterpillars acquire toxins from their host plants that render them unpalatable to most of their predators. For instance, ornate moth caterpillars utilize pyrrolizidine alkaloids that they obtain from their food plants to deter predators. The most aggressive caterpillar defenses are bristles associated with venom glands. These bristles are called urticating hairs . A venom which

3420-517: The hooves and horns of dead ungulates . Caterpillars are typically voracious feeders and many of them are among the most serious of agricultural pests . In fact, many moth species are best known in their caterpillar stages because of the damage they cause to fruits and other agricultural produce, whereas the moths are obscure and do no direct harm. Conversely, various species of caterpillar are valued as sources of silk, as human or animal food, or for biological control of pest plants. The origins of

3496-407: The larvae are fed by female workers. In Ropalidia marginata (a paper wasp) the males are also capable of feeding larvae but they are much less efficient, spending more time and getting less food to the larvae. The larvae of some organisms (for example, some newts ) can become pubescent and do not develop further into the adult form. This is a type of neoteny . It is a misunderstanding that

3572-525: The larval form always reflects the group's evolutionary history . This could be the case, but often the larval stage has evolved secondarily, as in insects. In these cases , the larval form may differ more than the adult form from the group's common origins. Within Insects , only Endopterygotes show complete metamorphosis, including a distinct larval stage. Several classifications have been suggested by many entomologists , and following classification

3648-892: The leaf surfaces. Some caterpillars, like early instars of the tomato hornworm and tobacco hornworm , have long "whip-like" organs attached to the ends of their body. The caterpillar wiggles these organs to frighten away flies and predatory wasps. Some caterpillars can evade predators by using a silk line and dropping off from branches when disturbed. Many species thrash about violently when disturbed to scare away potential predators. One species ( Amorpha juglandis ) even makes high pitched whistles that can scare away birds. Some caterpillars obtain protection by associating themselves with ants . The Lycaenid butterflies are particularly well known for this. They communicate with their ant protectors by vibrations as well as chemical means and typically provide food rewards. Some caterpillars are gregarious ; large aggregations are believed to help in reducing

3724-497: The leaves of such toxic plants. In addition to being unaffected by the poison, the caterpillars sequester it in their body, making them highly toxic to predators. The chemicals are also carried on into the adult stages. These toxic species, such as the cinnabar moth ( Tyria jacobaeae ) and monarch ( Danaus plexippus ) caterpillars, usually advertise themselves with the danger colors of red, yellow and black, often in bright stripes (see aposematism ). Any predator that attempts to eat

3800-522: The levels of parasitization and predation. Clusters amplify the signal of aposematic coloration, and individuals may participate in group regurgitation or displays. Pine processionary ( Thaumetopoea pityocampa ) caterpillars often link into a long train to move through trees and over the ground. The head of the lead caterpillar is visible, but the other heads can appear hidden. Forest tent caterpillars cluster during periods of cold weather. Caterpillars are eaten by many animals. The European pied flycatcher

3876-437: The life stages of European moths and butterflies, because he had believed that caterpillars were generated from water. When Merian published her study of caterpillars it was still widely believed that insects were spontaneously generated. Merian's illustrations supported the findings of Francesco Redi , Marcello Malpighi and Jan Swammerdam . Butterflies were regarded as symbol for the human soul since ancient time, and also in

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3952-708: The memory of a bad experience attenuates, the predator may have the experience reinforced through repetition. Aposematic organisms are often slow-moving, as they have little need for speed and agility. Instead, their morphology is frequently tough and resistant to injury, thereby allowing them to escape once the predator is warned off. Aposematic species do not need to hide or stay still as cryptic organisms do, so aposematic individuals benefit from more freedom in exposed areas and can spend more time foraging, allowing them to find more and better quality food. They may make use of conspicuous mating displays, including vocal signals, which may then develop through sexual selection . In

4028-477: The most common, but there have been fatalities. Lonomia is a frequent cause of envenomation in Brazil, with 354 cases reported between 1989 and 2005. Lethality ranging up to 20% with death caused most often by intracranial hemorrhage. Caterpillar hair has also been known to cause kerato - conjunctivitis . The sharp barbs on the end of caterpillar hairs can get lodged in soft tissues and mucous membranes such as

4104-906: The most toxic alkaloids among all living species. Within the same family, there are also cryptic frogs (such as Colostethus and Mannophryne ) that lack these toxic alkaloids. Although these frogs display an extensive array of coloration and toxicity, there is very little genetic difference between the species. Evolution of their conspicuous coloration is correlated to traits such as chemical defense, dietary specialization, acoustic diversification, and increased body mass. Some plants are thought to employ aposematism to warn herbivores of unpalatable chemicals or physical defences such as prickled leaves or thorns. Many insects, such as cinnabar moth caterpillars, acquire toxic chemicals from their host plants. Among mammals, skunks and zorillas advertise their foul-smelling chemical defences with sharply contrasting black-and-white patterns on their fur, while

4180-402: The moth. This is known as Batesian mimicry , after Henry Walter Bates , a British naturalist who studied Amazonian butterflies in the second half of the 19th century. Batesian mimicry is frequency dependent: it is most effective when the ratio of mimic to model is low; otherwise, predators will encounter the mimic too often. A second form of mimicry occurs when two aposematic organisms share

4256-438: The next day with the suggestion that since some caterpillars "...are protected by a disagreeable taste or odour, it would be a positive advantage to them never to be mistaken for any of the palatable catterpillars [ sic ], because a slight wound such as would be caused by a peck of a bird's bill almost always I believe kills a growing catterpillar. Any gaudy & conspicuous colour therefore, that would plainly distinguish them from

4332-468: The plants on which they feed. An example of caterpillars that use camouflage for defense is the species Nemoria arizonaria . If the caterpillars hatch in the spring and feed on oak catkins they appear green. If they hatch in the summer they appear dark colored, like oak twigs. The differential development is linked to the tannin content in the diet. Caterpillars may even have spines or growths that resemble plant parts such as thorns. Some look like objects in

4408-582: The poisonous beetles they ingest, could be included. It has been proposed that aposematism played a role in human evolution, body odour carrying a warning to predators of large hominins able to defend themselves with weapons. Perhaps the most numerous aposematic vertebrates are the poison dart frogs (family: Dendrobatidae ). These neotropical anuran amphibians exhibit a wide spectrum of coloration and toxicity. Some species in this poison frog family (particularly Dendrobates , Epipedobates , and Phyllobates ) are conspicuously coloured and sequester one of

4484-493: The position that in spite of changes it is still possible to know something, and that Alice is the same Alice at the beginning and end of a considerable interval. When the Caterpillar asks Alice to clarify a point, the child replies "I'm afraid I can't put it more clearly... for I can't but understand it myself, to begin with, and being so many different sizes in a day is very confusing". Here Carroll satirizes René Descartes ,

4560-403: The prey animal has defenses such as being unpalatable or poisonous. The easily detected warning is a primary defense mechanism, and the non-visible defenses are secondary. Aposematic signals are primarily visual, using bright colors and high-contrast patterns such as stripes. Warning signals are honest indications of noxious prey, because conspicuousness evolves in tandem with noxiousness. Thus,

4636-425: The primary reason for this unusual locomotion is the elimination of nearly all the prolegs except the clasper on the terminal segment. Caterpillars have soft bodies that can grow rapidly between moults. Their size varies between species and instars (moults) from as small as 1 millimetre (0.039 in) up to 14 centimetres (5.5 in). Some larvae of the order Hymenoptera (ants, bees, and wasps) can appear like

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4712-636: The risk of human contact in indoor environments. Caterpillars are a food source in some cultures. For example, in South Africa mopane worms are eaten by the bushmen , and in China silkworms are considered a delicacy. In the Old Testament of the Bible caterpillars are feared as pests that devour crops. They are part of the "pestilence, blasting, mildew, locust" because of their association with

4788-554: The same anti-predator adaptation and non-deceptively mimic each other, to the benefit of both species, since fewer individuals of either species need to be attacked for predators to learn to avoid both of them. This form of mimicry is known as Müllerian mimicry , after Fritz Müller , a German naturalist who studied the phenomenon in the Amazon in the late 19th century. Many species of bee and wasp that occur together are Müllerian mimics. Their similar coloration teaches predators that

4864-506: The same few individuals, the predator learning process would result in a stronger warning signal for surviving kin, resulting in higher inclusive fitness for the dead or injured individuals through kin selection . A theory for the evolution of aposematism posits that it arises by reciprocal selection between predators and prey, where distinctive features in prey, which could be visual or chemical, are selected by non-discriminating predators, and where, concurrently, avoidance of distinctive prey

4940-457: The signal's meaning. All of these results contradict the idea that novel, brightly coloured individuals would be more likely to be eaten or attacked by predators. Other explanations are possible. Predators might innately fear unfamiliar forms ( neophobia ) long enough for them to become established, but this is likely to be only temporary. Alternatively, prey animals might be sufficiently gregarious to form clusters tight enough to enhance

5016-407: The similarly-patterned badger and honey badger advertise their sharp claws, powerful jaws, and aggressive natures. Some brightly coloured birds such as passerines with contrasting patterns may also be aposematic, at least in females; but since male birds are often brightly coloured through sexual selection , and their coloration is not correlated with edibility, it is unclear whether aposematism

5092-510: The slugs of the family Phyllidiidae from Indo-Pacific coral reefs are aposematically coloured. Müllerian mimicry has been implicated in the coloration of some Mediterranean nudibranchs, all of which derive defensive chemicals from their sponge diet. The crown-of-thorns starfish , like other starfish such as Metrodira subulata , has conspicuous coloration and conspicuous long, sharp spines, as well as cytolytic saponins , chemicals which could function as an effective defence; this evidence

5168-520: The symbol of the caterpillar tends to depict a psychic transformation of a human. As such the caterpillar has in the Christian tradition become a metaphor for being "born again". Famously, in Lewis Carroll 's Alice's Adventures in Wonderland a caterpillar asks Alice "Who are you?". When Alice comments on the caterpillar's inevitable transformation into a butterfly, the caterpillar champions

5244-768: The trait eliminated before predators learn to avoid it. If warning coloration puts the first few individuals at such a strong disadvantage, it would never last in the species long enough to become beneficial. There is evidence for explanations involving dietary conservatism , in which predators avoid new prey because it is an unknown quantity; this is a long-lasting effect. Dietary conservatism has been demonstrated experimentally in some species of birds and fish. Further, birds recall and avoid objects that are both conspicuous and foul-tasting longer than objects that are equally foul-tasting but cryptically coloured. This suggests that Wallace's original view, that warning coloration helped to teach predators to avoid prey thus coloured,

5320-511: The upside-down Y-shaped suture on the front of the head. Lepidopteran caterpillars can be differentiated from sawfly larvae by: In 2019 , a geometrid moth caterpillar dating back to the Eocene epoch , approximately 44 million years ago , was found preserved in Baltic amber . It was described under Eogeometer vadens . Previously, another fossil dating back approximately 125 million years

5396-414: The warning signal to predators is shared, causing them to learn more quickly at less of a cost. A genuine aposematic signal that a species actually possesses chemical or physical defences is not the only way to deter predators. In Batesian mimicry , a mimicking species resembles an aposematic model closely enough to share the protection, while many species have bluffing deimatic displays which may startle

5472-438: The warning signal. If the species was already unpalatable, predators might learn to avoid the cluster, protecting gregarious individuals with the new aposematic trait. Gregariousness would assist predators to learn to avoid unpalatable, gregarious prey. Aposematism could also be favoured in dense populations even if these are not gregarious. Another possibility is that a gene for aposematism might be recessive and located on

5548-445: The warning. Among mammals, predators can be dissuaded when a smaller animal is aggressive and able to defend itself, as for example in honey badgers . Aposematism is widespread in insects, but less so in vertebrates , being mostly confined to a smaller number of reptile , amphibian , and fish species, and some foul-smelling or aggressive mammals . Pitohuis , red and black birds whose toxic feathers and skin apparently comes from

5624-504: The word "caterpillar" date from the early 16th century. They derive from Middle English catirpel , catirpeller , probably an alteration of Old North French catepelose : cate , cat (from Latin cattus ) + pelose , hairy (from Latin pilōsus ). The inchworm, or looper caterpillars from the family Geometridae are so named because of the way they move, appearing to measure the earth (the word geometrid means earth-measurer in Greek );

5700-436: Was correct. However, some birds (inexperienced starlings and domestic chicks) also innately avoid conspicuously coloured objects, as demonstrated using mealworms painted yellow and black to resemble wasps, with dull green controls. This implies that warning coloration works at least in part by stimulating the evolution of predators to encode the meaning of the warning signal, rather than by requiring each new generation to learn

5776-484: Was found in Lebanese amber . Many animals feed on caterpillars as they are rich in protein. As a result, caterpillars have evolved various means of defense. Caterpillars have evolved defenses against physical conditions such as cold, hot or dry environmental conditions. Some Arctic species like Gynaephora groenlandica have special basking and aggregation behaviours apart from physiological adaptations to remain in

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