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Widow Spider
''Latrodectus'' is a broadly distributed genus of spiders with several species that are commonly known as the true widows. This group is composed of those often loosely called black widow spiders, brown widow spiders, and similar spiders. However, the diversity of species is much greater. A member of the family Theridiidae, this genus contains 34 species, which include several North American "black widows" (southern black widow ''Latrodectus mactans'', western black widow ''Latrodectus hesperus'', and northern black widow ''Latrodectus variolus''). Besides these, North America also has the red widow ''Latrodectus bishopi'' and the brown widow ''Latrodectus geometricus'', which, in addition to North America, has a much wider geographic distribution. Elsewhere, others include the European black widow (''Latrodectus tredecimguttatus''), the Australian redback black widow (''Latrodectus hasseltii'') and the closely related New Zealand katipō (''Latrodectus katipo''), several differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectus Mactans
''Latrodectus mactans'', known as southern black widow or simply black widow, and the shoe-button spider, is a venomous species of spider in the genus ''Latrodectus''. The females are well known for their distinctive black and red coloring and for the fact that they will occasionally eat their mates after reproduction. The species is native to North America. The venom can cause pain and other symptoms, but is rarely fatal to healthy humans. Taxonomy ''Latrodectus mactans'' was first described by Johan Christian Fabricius in 1775, placing it in the genus '' Aranea''. It was transferred to the genus ''Latrodectus'' in 1837 by Charles Walckenaer and is currently placed in the family Theridiidae of the order Araneae. The species is closely related to ''Latrodectus hesperus'' (western black widow) and ''Latrodectus variolus'' (northern black widow). Members of the three species are often confused with the genus '' Steatoda'', the false widows. Prior to 1970, when the current taxonomi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectus Geometricus
''Latrodectus geometricus'', commonly known as the brown widow, brown button spider, grey widow, brown black widow, house button spider or geometric button spider, is one of the widow spiders in the genus ''Latrodectus''. As such, it is a 'cousin' to the more infamous ''Latrodectus mactans'' (black widow). ''L. geometricus'' has black and white patterns on the sides of its abdomen as well as an orange-yellow colored hourglass shape. Their eggs are easily identified by points that project from all over the egg sacs. ''L. geometricus'' are found all over the world, but are believed to originate in South America. Their bites, though painful, are not considered to be dangerous. Taxonomy ''L. geometricus'' derives its name from the geometric patterning on its abdomen. However, the spider's coloring can and does darken over time and the pattern may become obscured. Similar widows include the ''L. rhodesiensis'', a brown-colored relative of ''L. geometricus'' which is native to Z ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectism
Latrodectism () is the illness caused by the bite of '' Latrodectus'' spiders (the black widow spider and related species). Pain, muscle rigidity, vomiting, and sweating are the symptoms of latrodectism. There are several spider species all named black widow: southern black widow spider (''L. mactans''), the European black widow (''L. tredecimguttatus''), Western black widow spider (''L. hesperus''), Northern black widow spider (''L. variolus''). Other ''Latrodectus'' that cause latrodectism are the Australian redback spider (''L. hasselti''), the New Zealand katipō spider (''L. katipo'') and the South American '' Latrodectus corallinus'' and ''Latrodectus curacaviensis''. Several other members of the genus ''Latrodectus'' are not commonly associated with latrodectism including the cosmopolitan brown widow (''L. geometricus''). Signs and symptoms Symptoms of a bite depend on the amount of venom injected. A bite of ''Latrodectus'' may not in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider Bite
A spider bite, also known as arachnidism, is an injury resulting from the bite of a spider. The effects of most bites are not serious. Most bites result in mild symptoms around the area of the bite. Rarely they may produce a necrotic skin wound or severe pain. Most spiders do not cause bites that are of importance. For a bite to be significant, substantial envenomation is required. Bites from the widow spiders involve a neurotoxic venom which produces a condition known as latrodectism. Symptoms may include pain which may be at the bite or involve the chest and abdomen, sweating, muscle cramps and vomiting among others. Bites from the recluse spiders cause the condition loxoscelism, in which local necrosis of the surrounding skin and widespread breakdown of red blood cells may occur. Headaches, vomiting and a mild fever may also occur. Other spiders that can cause significant bites include the Australian funnel-web spider and South American wandering spider. Efforts to pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectus Bishopi
''Latrodectus bishopi'' is the scientific name for the red widow spider, which is endemic to certain habitats of central and southern Florida, where it lives primarily in sand dunes dominated by sand pine, ''Pinus clausa'' – a type of vegetation found only in peninsular Florida. Description The red widow, ''L. bishopi'', has a red-orange cephalothorax, its abdomen is black with yellow rings outlining the rows of red spots and its legs are vermillion red. On its underside, it does not have the familiar hourglass marking and instead usually has one or two small red marks. Females are almost double the size of the male. ;Venom ''L. bishopi'' has been reported to be venomous like the other '' Latrodectus'' members, though no bites by this spider are recorded in the medical literature; unlike cosmopolitan species such as the black and brown widows, it seldom comes into contact with humans. The median lethal dose () of the spider's venom has been measured in mice as 2.20 mg/k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectus Hesperus
''Latrodectus hesperus'', the western black widow spider or western widow, is a venomous spider species found in western regions of North America. The female's body is 14–16 mm (1/2 in) in length and is black, often with an hourglass-shaped red mark on the lower abdomen. This "hourglass" mark can be yellow, and on rare occasions, white. The male of the species is around half this length and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of '' Latrodectus mactans'' and it is closely related to the northern species '' Latrodectus variolus''. The species, as with others of the genus, build irregular or "messy" webs: unlike the spiral webs or the tunnel-shaped webs of other spiders, the strands of a ''Latrodectus'' web have no apparent organization. Female black widows have potent venom containing a neurotoxin active against a range of mammals (see latrodectism). In humans, symptoms of this venom include pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrotoxin
A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus ''Latrodectus'' (widow spiders) as well as at least one species of another genus in the same family, '' Steatoda nobilis''. Latrotoxins are the main active components of the venom and are responsible for the symptoms of latrodectism. The following latrotoxins have been described: five insecticidal toxins, termed α, β, γ, δ and ε-latroinsectotoxins, one vertebrate-specific neurotoxin, alpha-latrotoxin, and one toxin affecting crustaceans, α-latrocrustatoxin. α-Latrotoxin The best-studied latrotoxin is alpha-latrotoxin, which acts presynaptically to release neurotransmitters (including acetylcholine) from sensory and motor neurons, as well as on endocrine cells (to release insulin, for example). It is a ~130 kDa protein that exists mainly in its dimerized or tetramerized forms. α-Latrotoxin (α-LTX) can naturally be found in widow spiders of the genus ''Latrodectus''. The most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectus Eye Group
''Latrodectus'' is a broadly distributed genus of spiders with several species that are commonly known as the true widows. This group is composed of those often loosely called black widow spiders, brown widow spiders, and similar spiders. However, the diversity of species is much greater. A member of the family Theridiidae, this genus contains 34 species, which include several North American "black widows" (southern black widow '' Latrodectus mactans'', western black widow ''Latrodectus hesperus'', and northern black widow '' Latrodectus variolus''). Besides these, North America also has the red widow '' Latrodectus bishopi'' and the brown widow ''Latrodectus geometricus'', which, in addition to North America, has a much wider geographic distribution. Elsewhere, others include the European black widow (''Latrodectus tredecimguttatus''), the Australian redback black widow (''Latrodectus hasseltii'') and the closely related New Zealand katipō (''Latrodectus katipo''), severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latrodectus Curacaviensis
''Latrodectus curacaviensis'' is a species of black widow spider, that belongs to the genus ''Latrodectus''. It is known as the South American black widow, Brazilian black widow or Araña del trigo. Description Like many black widow species, females are larger than males, growing up to 11–17 mm, with their body and legs black and red. Males are much smaller, known by their long legs, and white or brown color. ''Latrodectus curacaviensis'' is mainly nocturnal. It is not aggressive to humans, but females will attack to defend their egg sacs. It feeds on small insects. They have a distinct hourglass mark with a black diamond shape and four red triangles in a square. Bites are rare but dangerous. Distribution and habitat It has been reported in the Lesser Antilles and South America. It is usually found under logs, in sheds, stone fireplaces, near trash and debris. Venom The venom contains excitatory neurotoxins ( alpha-latrotoxins). Bites usually deliver only small amou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Cannibalism
Sexual cannibalism is when an animal, usually the female, cannibalizes its mate prior to, during, or after copulation.Polis, G.A. & Farley, R.D. Behavior and Ecology of Mating in the journal of Arachnology 33-46 (1979). It is a trait observed in many arachnid orders and several insect orders. Several hypotheses to explain this seemingly paradoxical behavior have been proposed. The adaptive foraging hypothesis,Blamires, S.J. Nutritional implications for sexual cannibalism in a sexually dimorphic orb web spider. Austral Ecology 36, 389-394 (2011). aggressive spillover hypothesisArnqvist, G. Courtship behaviour and sexual cannibalism in the semi-aquatic fishing spider, DOLOMEDES FIMBRIATUS (CLERCK) (ARANEAE: PISAURIDAE).pdf. The journal of Arachnology 20, 222-226 (1992). and mistaken identity hypothesisGould, S. Only his wings remained. Natural History 93, 10-18 (1984). are among the proposed hypotheses to explain how sexual cannibalism evolved. This behavior is believed to have evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
