40-406: See text The genus Lonomia is a moderate-sized group of fairly cryptic saturniid moths from South America , famous not for the adults, but for their highly venomous caterpillars , which are responsible for a few deaths each year, especially in southern Brazil , and the subject of hundreds of published medical studies. They are commonly known as giant silkworm moth , a name also used for
80-537: A disruptive pattern is to prevent, or to delay as long as possible, the first recognition of an object by sight... irregular patches of contrasted colours and tones ... tend to catch the eye of the observer and to draw his attention away from the shape which bears them. Further, Cott criticises unscientific attempts at camouflage, early in the Second World War , for not understanding the principles involved: Various recent attempts to camouflage tanks, armoured cars and
120-454: A group of these caterpillars that are gathered on the trunk of a tree. The effects of a dose from multiple caterpillars can be dramatic and severe, including massive internal hemorrhaging , kidney failure , and hemolysis . The resulting medical syndrome is sometimes called lonomiasis. Death may result, either rapidly or after many days following envenomation. The LD 50 of the Lonomia venom
160-448: A highly irregular outline. For example, the comma butterfly , Polygonia c-album , is highly cryptic when its wings are closed, with cryptic colours, disruptive pattern, and irregular outer margins to the wings. The possibility of protective coloration in plants has been little studied. T. J. Givnish and Simcha Lev-Yadun have proposed that leaf variegation with white spots may serve as camouflage in forest understory plants, where there
200-441: A military vehicle may have a variety of backgrounds. Conversely, poisonous or distasteful animals that advertise their presence with warning coloration ( aposematism ) use patterns that emphasize rather than disrupt their outlines. For example, skunks , salamanders and monarch butterflies all have high-contrast patterns that display their outlines. The artist Abbott Handerson Thayer in his 1909 book Concealing-Coloration in
240-454: A mother does not affect survival, Mitchell suggests that young giraffes must be extremely well camouflaged. This is supported by the fact that coat markings are strongly inherited. Conversely, far from hiding, adult giraffes move about to gain the best view of an approaching predator, relying on their size and ability to defend themselves even from lions. The outlines of an animal's body can be made hard to see by other methods, such as by using
280-422: A nonrepetitive configuration, that also provide camouflage by disrupting the recognizable shape or orientation of the animal", as in the cuttlefish. The strategy appears paradoxical and counter-intuitive as a method of camouflage, since disrupting outlines depends on using patches of colour which contrast strongly with each other, so the patches are themselves conspicuous. While background matching works best for
320-475: A plain background", but at once adds that conditions are hardly ever ideal, as they are constantly changing, as is the light. Therefore, Cott argues, camouflage has to break up the perceived continuous surfaces of an object and its outlines. In his own words, "for effective concealment, it is essential that the tell-tale appearance of form should be destroyed." He draws an analogy with a pickpocket who carefully distracts your attention, arguing that: The function of
360-539: A single background, disruptive coloration is a more effective strategy when an animal or a military vehicle may have a variety of backgrounds. Martin Stevens and colleagues in 2006 made what they believed was the first experimental test that "disruptive coloration is effective even when some colour patches do not match the background and have a high contrast with both the background and adjacent pattern elements (disruptive contrast)". They used "moth-like targets", some matching
400-501: A strongly contrasting pattern. It is often combined with other methods of crypsis including background colour matching and countershading ; special cases are coincident disruptive coloration and the disruptive eye mask seen in some fishes, amphibians, and reptiles. It appears paradoxical as a way of not being seen, since disruption of outlines depends on high contrast, so the patches of colour are themselves conspicuous. The importance of high-contrast patterns for successful disruption
440-449: A wide range of other saturniid moths. The caterpillars are themselves extremely cryptic, blending in against the bark of trees, where the larvae commonly aggregate. The larvae, like most hemileucines , are covered with urticating hairs , but these caterpillars possess a uniquely potent anticoagulant venom. A typical envenomation incident involves a person unknowingly leaning against, placing their hand on, or rubbing their arm against
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#1732852449660480-462: Is 0.19 mg for an 18–20 g mouse ( IV ); however, due to the small amount of venom in the bristles of the caterpillar, the rate of human fatality is only 1.7%. While there are more than a dozen species in the genus, the most troublesome species is Lonomia obliqua , and it is this species on which most of the medical research has centered. As anticoagulants have some very beneficial applications (e.g., prevention of life-threatening blood clots)
520-422: Is a dappled background. Lev-Yadun has also suggested, however, that similar markings serve as conspicuous warning coloration in well-defended thorny plants of open habitats, where the background is uniformly bright. Givnish found a correlation of leaf mottling with closed habitats. Disruptive camouflage would have a clear evolutionary advantage in plants: they would tend to escape from being eaten by herbivores ; and
560-569: Is apparently the basal and predominant use of almost all the bolder patterns in animals' costumes. Hugh Cott 's 1940 book Adaptive Coloration in Animals introduced ideas such as "maximum disruptive contrast". This uses streaks of boldly contrasting colour, which paradoxically make animals or military vehicles less visible by breaking up their outlines. He explains that in ideal conditions, background colour matching together with countershading would "suffice to render an animal absolutely invisible against
600-404: Is no background. As a strategy, crypsis is used by predators against prey and by prey against predators . Crypsis also applies to eggs and pheromone production. Crypsis can in principle involve visual, olfactory, or auditory camouflage. Many animals have evolved so that they visually resemble their surroundings by using any of the many methods of natural camouflage that may match
640-430: Is visual, the term cryptic coloration , effectively a synonym for animal camouflage, is sometimes used, but many different methods of camouflage are employed in nature. There is a strong evolutionary pressure for prey animals to avoid predators through camouflage, and for predators to be able to detect camouflaged prey. There can be a self-perpetuating coevolution , in the shape of an evolutionary arms race , between
680-476: The large blue butterfly caterpillar) to trick the ants into feeding them. Pirate perch ( Aphredoderus sayanus ) may exhibit chemical crypsis, making them undetectable to frogs and insects colonizing ponds. Trained dogs and meerkats, both scent-oriented predators, have been shown to have difficulty detecting puff adders , whose strategy of ambushing prey necessitates concealment from both predators and prey. Some insects, notably some Noctuid moths , (such as
720-469: The large yellow underwing ), and some tiger moths , (such as the garden tiger ), have been supposed to defend themselves against predation by echolocating bats, both by passively absorbing sound with soft, fur-like body coverings and by actively creating sounds to mimic echoes from other locations or objects. The active strategy was described as a "phantom echo" that might therefore represent "auditory crypsis" with alternative theories about interfering with
760-566: The 1940s have been disruptively coloured, and with the issue of US Woodland pattern to United States armed forces from 1981, disruptive pattern became a dominant feature of military uniforms. From 1969, Disruptive Pattern Material (DPM) began to replace plain material for uniforms in the British Armed Forces and was later used by many other armies. Three major challenges face the design of disruptively patterned uniforms. Firstly, units frequently move from one terrain to another, where
800-676: The Animal Kingdom argued that animals were concealed by a combination of countershading and "ruptive" marks, which together "obliterated" their self-shadowing and their shape. Thayer explained that: Markings... of whatever sort, tend to obliterate ,—to cancel, by their separate and conflicting pattern, the visibility of the details and boundaries of form.... If the bird's or butterfly's costume consists of sharply contrasted bold patterns of light and dark, in about equal proportions, its contour will be "broken up" against both light and dark—light failing to show against light, dark against dark. Such
840-408: The background colours and contrasts may differ greatly. A uniform designed for woodland will be too strongly contrasting for desert use, and too green for urban use. Therefore, no single camouflage pattern is effective in all terrains. The American UCP of 2004 attempted to suit all environments but was withdrawn after a few years of service. Terrain specific patterns like "Berlin camouflage", which
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#1732852449660880-797: The background is brighter than is possible even with white pigment, counter-illumination in marine animals, such as squid, can use light to match the background. Some animals actively camouflage themselves with local materials. The decorator crabs attach plants, animals, small stones, or shell fragments to their carapaces to provide camouflage that matches the local environment. Some species preferentially select stinging animals such as sea anemones or noxious plants, benefiting from aposematism as well as or instead of crypsis. Some animals, in both terrestrial and aquatic environments, appear to camouflage their odor, which might otherwise attract predators. Numerous arthropods, both insects and spiders, mimic ants , whether to avoid predation, to hunt ants, or (as in
920-433: The bats' echolocation ("jamming"). Subsequent research has provided evidence for only two functions of moth sounds, neither of which involve "auditory crypsis". Tiger moth species appear to cluster into two distinct groups. One type produces sounds as acoustic aposematism , warning the bats that the moths are unpalatable, or at least performing as acoustic mimics of unpalatable moths. The other type uses sonar jamming. In
960-477: The boundary of the animal and the background". Disruptive patterns use strongly contrasting markings such as spots or stripes to break up the outlines of an animal or military vehicle. Some predators, like the leopard , and some potential prey like the Egyptian nightjar , use disruptive patterns. Disruptive patterns are defined by A. Barbosa and colleagues as "characterized by high-contrast light and dark patches, in
1000-596: The color and texture of the surroundings (cryptic coloration) and/or break up the visual outline of the animal itself ( disruptive coloration ). Such animals, like the tawny dragon lizard , may resemble rocks, sand, twigs, leaves, and even bird droppings ( mimesis ). Other methods including transparency and silvering are widely used by marine animals . Some animals change color in changing environments seasonally, as in ermine and snowshoe hare , or far more rapidly with chromatophores in their integuments, as in chameleon and cephalopods such as squid . Countershading ,
1040-409: The conclusion that their patterns are for camouflage appear counterintuitive: but when standing among trees and bushes, their camouflage is effective at even a few metres' distance. Further, young giraffes are much more vulnerable to predation than adults: between 60% and 75% of calves die within a year. Mothers hide their calves, which spend much of the time lying down in cover. Since the presence of
1080-601: The effect and render the work practically useless. The pioneering work of Thayer and Cott is endorsed in the 2006 review of disruptive coloration by Martin Stevens and colleagues, which notes that they proposed a "different form of camouflage" from the traditional "strategy of background matching" proposed by authors such as Alfred Russel Wallace ( Darwinism , 1889), Edward Bagnall Poulton ( The Colours of Animals , 1890) and Frank Evers Beddard ( Animal Coloration , 1895); Stevens observes that background matching on its own would always fail because of "discontinuities between
1120-468: The enemy observing the pattern. A pattern printed with small patches of colour blends into a single perceived mass at a certain range, defeating the disruptive effect. Conversely, a pattern printed with large patches of colour appears conspicuous at shorter ranges. This problem has been solved with pixellated shapes, often designed digitally, that provide a fractal -like range of patch sizes, enabling them to be effectively disruptive both at close range and at
1160-452: The eye with a disruptive eye mask , sometimes contrasting with a stripe above the eye , making it seem just part of a dark area of background. Cott called this a special case of a " coincident disruptive pattern ". Another camouflage mechanism, distractive markings , also involves conspicuous marks and has for a century since Thayer's initial description been conflated with it, but the two require different kinds of marking. For distraction,
1200-513: The hypothesis is testable. Disruptive coloration is common in military usage, for military vehicles, for firing positions and other installations, and for individual soldiers, where uniforms, equipment such as helmets, and face paint may be used to break up outlines and features. Disruptive coloration, however, does not always achieve crypsis on its own, as an animal or a military target may be given away by other factors including shape, shine, and shadow. Many military camouflage patterns since
1240-400: The latter type of moth, detailed analyses failed to support a "phantom echo" mechanism underlying sonar jamming, but instead pointed towards echo interference. Disruptive coloration Disruptive coloration (also known as disruptive camouflage or disruptive patterning ) is a form of camouflage that works by breaking up the outlines of an animal, soldier or military hardware with
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1280-761: The lightness of the background oak tree bark, other mismatching it, each with a dead mealworm. If the mealworm was removed it was assumed a bird predator had taken it: this could be distinguished from visits by other predators. They found that disruptive coloration provided the best protection from bird predators when the pattern was matched to background luminance, but even when elements in a pattern did not match, disruptive patterns were still better at reducing predation than either non-disruptive patterns or plain (unpatterned) control targets. Disruptive patterns can also conceal specific features. Animals such as fish, birds, frogs and snakes can readily be detected by their eyes, which are necessarily round and dark. Many species conceal
1320-513: The markings should be small and should avoid the prey's outline so as to take attention away from it, whereas disruptive markings should contact the outline so as to break it up. Many poisonous or distasteful animals that advertise their presence with warning coloration ( aposematism ) use patterns that emphasize rather than disrupt their outlines. For example, skunks , salamanders and monarch butterflies all have high contrast patterns that display their outlines. These advertising patterns exploit
1360-574: The opposite principle to disruptive coloration, for what is in effect the exactly opposite effect: to make the animal as conspicuous as possible. Some Lepidoptera, including the wood tiger moth , are aposematic and disruptively coloured; against a green, vegetative background their bright aposematic coloration stands out, but on the ground their wings camouflage them among dead leaves and dirt. The presence of bold markings does not in itself prove that an animal relies on camouflage. According to Mitchell, adult giraffes are "inescapably conspicuous", making
1400-407: The perceptive abilities of animals attempting to detect the cryptic animal and the cryptic characteristics of the hiding species. Methods of crypsis include (visual) camouflage, nocturnality , and subterranean lifestyle. Camouflage can be achieved by a wide variety of methods , from disruptive coloration to transparency and some forms of mimicry , even in habitats like the open sea where there
1440-494: The research is motivated by the possibility of deriving some pharmaceutically valuable chemicals from the toxin. Crypsis In ecology , crypsis is the ability of an animal or a plant to avoid observation or detection by other animals. It may be a predation strategy or an antipredator adaptation . Methods include camouflage , nocturnality , subterranean lifestyle and mimicry . Crypsis can involve visual, olfactory (with pheromones ) or auditory concealment. When it
1480-490: The roofs of buildings with paint reveal an almost complete failure by those responsible to grasp the essential factor in the disguise of surface continuity and of contour. Such work must be carried out with courage and confidence, for at close range objects properly treated will appear glaringly conspicuous. But they are not painted for deception at close range, but at ranges at which ... bombing raids are likely... And at these distances differences of tint ... blend and thus nullify
1520-511: The use of different colors on upper and lower surfaces in graduating tones from a light belly to a darker back, is common in the sea and on land. It is sometimes called Thayer's law, after the American artist Abbott Handerson Thayer , who published a paper on the form in 1896 that explained that countershading paints out shadows to make solid objects appear flat, reversing the way that artists use paint to make flat paintings contain solid objects. Where
1560-497: Was applied to British vehicles operating in Berlin during the Cold War , have sometimes been developed but are ineffective in other terrains. Secondly, the effectiveness of any pattern in disrupting a soldier's outlines varies with lighting, depending on the weather and the height of the sun in the sky. And thirdly, any given patch of printed colour varies in apparent size with distance from
1600-404: Was predicted in general terms by the artist Abbott Thayer in 1909 and explicitly by the zoologist Hugh Cott in 1940. Later experimental research has started to confirm these predictions. Disruptive patterns work best when all their components match the background. While background matching works best for a single background, disruptive coloration is a more effective strategy when an animal or
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