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30-550: A stinger is an organ or body part found in various animals, typically arthropods, that usually delivers some kind of venom Stinger may also refer to: Stinger An insect sting is complicated by its introduction of venom , although not all stings are venomous. Bites, which can introduce saliva as well as additional pathogens and diseases, are often confused with stings, and vice versa. Specific components of venom are believed to give rise to an allergic reaction , which in turn produces skin lesions that may vary from

60-474: A toxin in which formic acid is one recognized constituent, and the other secreting an alkaline neurotoxin ; acting independently, each toxin is rather mild, but when they combine through the sting, the combination has strong irritating properties. In a small number of cases, the second occasion of a bee or wasp sting causes a severe allergic reaction known as anaphylaxis . While the overwhelming majority of insects withdraw their stingers from their victims,

90-432: A few insects leave them in the wounds. For example, of the 20,000 species of bees worldwide, only the half-dozen species of honeybees ( Apis ) are reported to have a barbed stinger that cannot be withdrawn; of wasps, nearly all are reported to have smooth stingers with the exception of two species, Polybia rejecta and Synoeca surinama . A few non-insect arthropods, such as scorpions , also sting. Among arthropods ,

120-412: A gland that secretes an acrid fluid. The points of these bristles usually break off in the wound, and the acrid fluid is pressed into it. Various plants unrelated to true nettles ( Urtica species) possess similar defensive bristles, and the common names often reflect this (e.g. " bull nettle "). Many cacti of the sub-family Opuntioideae feature fine, loosely attached short spines called glochids . When

150-403: A pain-producing agent and the other in the distribution and penetration of the paralyzing components to vulnerable sites in the offender. This helps in the rapid immobilization of the animal or of the body parts receiving the venom. Spiders only bite, although some tarantulas have barbed bristles called urticating hairs . Certain caterpillars also have urticating hairs. Centipedes also possess

180-413: A small itching weal, or slightly elevated area of the skin, to large areas of inflamed skin covered by vesicles and crusted lesions . Stinging insects produce a painful swelling of the skin, the severity of the lesion varying according to the location of the sting, the identity of the insect and the sensitivity of the subject. Many species of bees and wasps have two poison glands, one gland secreting

210-404: A sting or stinger is a sharp organ, often connected with a venom gland and adapted to inflict a wound by piercing, as with the caudal sting of a scorpion . Stings are usually located at the rear of the animal. Animals with stings include bees, wasps (including hornets ), some ants like fire ants , and scorpions , as well as a single beetle species ( Onychocerus albitarsis ) that can deliver

240-540: A tarantula's or caterpillar's abdomen. Many tarantula species eject bristles from their abdomens, directing them toward potential attackers. These bristles can embed themselves in the other animal's skin or eyes, causing physical irritation, usually to great discomfort. The term "hairs" is technically a misnomer, as only mammals possess true hairs . The scientific term for plant hairs is trichomes . The most common form of urticating hairs in plants are typified by nettles, which possess sharp-pointed hollow bristles seated on

270-472: A venomous bite rather than a sting, inflicted with a highly modified first pair of legs, called forcipules . Organs that perform similar functions in non-arthropods are often referred to as "stings". These organs include the modified dermal denticle of the stingray , the venomous spurs on the hind legs of the male platypus , and the cnidocyte tentacles of the jellyfish . Urticating hairs Urticating hairs or urticating bristles are one of

300-431: A venomous sting from its antennae, whose terminal segments have evolved to resemble a scorpion's tail. In all stinging Hymenoptera the sting is a modified ovipositor . Unlike most other stings, honey bee workers' stings are strongly barbed and lodge in the flesh of mammals upon use, tearing free from the honey bee's body, killing the bee within minutes. The sting has its own ganglion , and it continues to saw into

330-612: Is believed to target different enemies. Defined targets for some bristle types are unknown. Type II is usually not kicked off by the tarantula, rather delivered by direct contact. However, there is at least one aviculariine species— Caribena versicolor —which can kick type II urticating hairs off of the abdomen, similarly to species from the subfamily Theraphosinae. Tarantulas from the genera Avicularia , Pachistopelma and Iridopelma possess Type II hairs (Hoover, 1997). Type III urticating hairs are most efficient for defense against vertebrates and invertebrates. Types III and IV are

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360-462: Is life-threatening to humans. Stings do not often occur as a defense, but are mainly the result of brushing against the spines. However, many species, whose larvae are armed with these bristles, have evolved to utilize them as a defense mechanism against any perceived threat. For example, many larvae in the family Lasiocampidae bear dense bands of short, stinging bristles across their thoracic segments. The bristles are normally retracted into folds in

390-631: Is not barbed and can be used to sting repeatedly. The description of barbed or unbarbed is not precise: there are barbs on the stings of yellowjacket wasps and the Mexican honey wasp , but the barbs are so small that the wasp can sometimes withdraw its sting apparatus from victim's skin. The stings of some wasps, such as those of the Polistes versicolor , contain relatively large amounts of 5-hydroxytryptamine (5-HT) in its venoms. The 5-HT in these venoms has been found to play at least two roles: one as

420-658: The Chilean rose tarantula ( Grammastola rosea ) and the pinktoe tarantula ( Avicularia avicularia ), are fairly mild and innocuous to humans. Others, such as those of the Brazilian giant white knee tarantula ( Acanthoscurria geniculata ), are moderately irritating. Still others, such as the Goliath birdeater ( Theraphosa blondi ), are far more severe. These bristles can result in painful rashes, and have been likened to sharp shards of fiberglass. After kicking urticating hairs,

450-442: The opisthosoma throwing the urticating hairs in the direction of the enemy. The cloud of small bristles can get into the mucous membrane of small mammals and cause edema , which can be fatal. The bristles cause both mechanical and chemical harm to the skin and membranes. Humans' reaction and the degree of irritation to a defensive urticating hair barrage can vary tremendously, based on the species in question. Some, such as those of

480-712: The appearance of a similar-looking, toxic, species as a means of protection. For example (in reptiles), the coral snakes (family Elapidae ) are well-known as venomous, while the non-venomous milk snakes ( Colubridae ) appear visually very similar, utilizing mimicry to their advantage. If roughly stimulated or held, lasiocampid larvae are likely to writhe and lash about, forcing the stinging bristles into any vulnerable surface they can. Many other species of larvae lack any such localized concentrations of bristles and are armed more generally with urticating hairs; even so, they too will lash about frantically if disturbed, making them difficult to handle without suitable equipment. Toxins from

510-484: The broken bristles may spill out, causing dermatitis on the surface of the skin. For brown-tail moths ( Euproctis chrysorrhoea ) native to Europe and invasive in other parts of the world, bristles are shed or broken off during molts and can be wind-borne, so that direct contact with live or dead larvae is not required to trigger a rash. In spite of such defenses, some species of birds feed avidly on "hairy" caterpillars, grabbing them in their beaks and scrubbing them on

540-430: The ground until the majority of the bristles have been stripped or damaged; at least a few species of cuckoos, apparently, collect the bristles in their digestive tracts until they form 'pellets' to be regurgitated. Examples of predators other than cuckoos that feed on "hairy" caterpillars include several reptiles and insectivorous mammal species, from several continents. Urticating hairs (setae) are found in about 90% of

570-430: The main tone of abdomen. Despite this shift, urticating hairs nonetheless retain unique characteristics that render them visually distinct from abdominal bristles, such as their tendency to cover only a portion instead of the entirety of the opisthosoma . There are seven different types of urticating hair known in tarantulas, varying in size and shape, particularly the distribution of barbs. Each type of urticating hair

600-644: The most irritating to mammalian predators. Not all urticating hair types are exhibited by each species of tarantula. Type II urticating hairs can be found in the genera Avicularia , Iridopelma and Pachistopelma (subfamily Aviculariinae). Type I and III urticating hairs are representative on a wide diversity of large bodied genera in the subfamily Theraphosinae: Lasiodora , Acanthoscurria , Nhandu , Megaphobema , Sericopelma , Eupalaestrus , Proshapalopus , Brachypelma , Cyrtopholis , and others, although some only have Type I in mature males. Unusually, Type III urticating hairs are found only on

630-432: The pedipalps. They are much shorter and lighter in contrast with other types of urticating hair. These are easily thrown by the spider into the air. Type VI urticating hairs are found in the genus Hemirrhagus . Genera with the most urticating hairs are Lasiodora , Grammostola and Acanthoscurria . New World tarantulas will, at the moment of danger, turn toward the attacker and briskly rub their hind legs against

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660-401: The plant is disturbed many of these spines fall off and penetrate the skin, causing irritation. Many glochidia are barbed, complicating their removal and enhancing their persistence in the skin. Exposure to glochidia is an occupational hazard to fruit pickers and other outside workers in areas where Opuntioideae thrive, as the spines can persist in clothing and gloves and can become airborne under

690-431: The primary defense mechanisms used by numerous plants, almost all New World tarantulas , and various lepidopteran caterpillars . Urtica is Latin for "nettle" (stinging nettles are in the genus Urtica ), and bristles that urticate are characteristic of this type of plant, and many other plants in several families. This term also refers to certain types of barbed bristles that cover the dorsal and posterior surface of

720-406: The right conditions. Several lepidopteran families include species whose larvae bear urticating hairs. Families prominent in this respect include the following: Adults of some species also have urticating scales, and some species shed some of their urticating hairs as defense for their pupae and eggs. The urticating setae , or spines, can cause irritation when they break off and lodge in

750-431: The skin of larger animals or humans. In some species, the setae are hollow, connecting to venom -producing cells, like a hypodermic needle . Generally, setae are only externally irritating, but may be more dangerous if contact is made with mucous membranes or if ingested; some can cause severe skin necrosis , eczema -like symptoms and shedding . Certain species of Lonomia (family Saturniidae ) can inject venom that

780-451: The skin, but, if the caterpillar is disturbed, it will display its bristles, which are usually of contrasting colors; in nature, bright and/or contrasting colors are used by many invertebrates , amphibians , reptiles , fungi and plants as visual warnings for predators, indicating the presence of toxicity, venom or poison. The same defensive adaptation may also be seen as a 'bluff' technique in certain harmless species, in which they mimic

810-406: The species of Theraphosa , but these otherwise are similar to many species that also have Type I hairs. Type III alone is found in many 'dwarf' new world genera, e.g. Hapalopus . Type IV is found in several South American genera, e.g. Grammostola , Euathlus etc. (exhibits types III and IV). Type V urticating hairs are typical of the species of the genus Ephebopus . They are located on

840-489: The species of tarantula (spiders of the family Theraphosidae) found in the New World . They are not found in tarantulas from other parts of the world. Urticating hairs do not appear at birth but form with each consecutive molt , widening from molt to molt and outwardly presenting themselves around areas of more dark bristles on the upper back part of the abdomen of juveniles. In elder ages their coloration shifts to match

870-468: The tarantula will have a bald spot on its abdominal region. Urticating hairs are not just thrown at an enemy as a first line defense, but are also used as an indication of territory. They can be found on and around the burrow entrance and in webbing for protection (for example, some subfamily Theraphosinae species include these bristles in cocoon silk). Urticating hairs protect tarantula egg sacs ( Avicularia spp. and Theraphosa blondi , respectively). This

900-548: The target's flesh and release venom for several minutes. This trait is of obvious disadvantage to the individual but protects the hive from attacks by large animals; aside from the effects of the venom, the remnant also marks the stung animal with honey bee alarm pheromone. The barbs of a honey bee's attack are only suicidal if the skin is elastic, as is characteristic of vertebrates such as birds and mammals; honey bees can sting other insects repeatedly without dying. The sting of nearly all other bees and other sting-bearing organisms

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