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Paper Abstract: Examination of the widow spiders as most dangerous to humans in North America. Spiders as arthopods. Scientific analysis of the species. Webs of black widow. Three types of black widow spiders in the U.S. Description of the Southern, Western and Northern female. The European black widow. Adult male black widow spiders. Mating process. Spider bites. Paper Introduction: Spiders are arachnids, a group of arthropods which includes scorpions, harvestmen, mites, and ticks (Akre, Catts and Antonelli, 2001). Spiders have jointed legs and a hard external or outer skeleton. They have four pairs of legs, and the body is divided into two sections, the cephalothorax and the abdomen, whereas insects have six legs and their bodies are divided into three sections, head, thorax and abdomen. Spiders have no wings or antennae, but they do have large, sharply pointed jaws which are their fangs (chelicerae). All spiders are predators, and they feed on a variety of insects and other soft-bodied invertebrate animals (Akre, Catts and Antonelli, 2001). Spiders attack and subdue their prey by biting them with their fangs and injecting them with poison. All spiders spin silk, but not all of them use it to spin webs. Most spide Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. (1997). cities. They mature in from two tofour months, depending on the food supply. Females mature about 9 days after they emerge fromthe egg sac, and live for another six months to a year. Spiders.Http://cru.cache.wsu.edu/CEPublications/eb1548.html Crew, G. The spiderlings climb to the topof some vegetation or other object and spin webs. (1997). Spiderlingsoverwinter in late season egg sacs until they emerge in the spring (Oi andShelton, 1997). However, if she is disturbed while guarding her eggs, shewill bite the intruder. L. Eightlong, delicate legs arise from the small front body segment. Mating is an elaborate process which begins when a wandering maleblack widow spider encounters a webbing female. As they develop, the spiderlings look similar in appearance to adultmales, though smaller. Males mature inabout 7 days after emerging from the egg sacs, and only live for anotherone or two months. Spiders have no wings orantennae, but they do have large, sharply pointed jaws which are theirfangs (chelicerae). The hesperus is the most common black widow spider in the westernUnited States, and is found in large numbers in Arizona, California, andother western states. Latrodectus mactans producesnearly spherical eggs sacs with a grayish tinge; Latrodectus hesperusproduces egg sacs which are typically creamy yellow to tan, and they arenever gray, but are more pear shaped than spherical; Latrodectus variolusproduces egg sacs which are typically yellow or tan, and are more pearshaped. (2 1). (2 1). The female is alerted when prey is snared by the webby vibrations of the threads (Oi and Shelton, 1997). With each molt, the spiderlingsgain more black coloration (eNature, 2 1). The widow spiders, genus Latrodectus, are the largest of the comb-footed weaving family Theridiidae, and all species are poisonous (Vest,1999). The males have smaller bodies, longer legs, and usuallyhave yellow and red bands and spots over the back, as do the immaturestages (Lyon, 1997). Black widow spiders rarely build theirwebs in houses (Kaston, 2 1).. Thefemale widow spider is more aggressive when she is protecting an egg sac.Otherwise, they normally retreat to the edge of the web when disturbed.The sacs are white to tan in color, and have a paper-like texture. The male issmaller than the female and has four pairs of red marks along the sides ofthe abdomen. It is also found around human habitats and evendowntown in western U. The western widow also causes a large number ofspider bites, again in the southern part of its range (Vest, 1999). Severe acute symptoms, if theyoccur, usually go away in two to three days (Smith, 2 1). The term "black widow" refersto those in the United States, Europe, and some other areas, which have ashiny black appearance. Black widows belong to the family Theridiidae, a group of spiders alsoknown as the comb-footed spiders because of the specialized comb-likestructure on tarus IV (Kaston, 2 1). (2 1). If she is receptive to the male's advances, shewill remain motionless long enough for the male to deposit sperm in hergenital opening. Adult male black widow spiders wander in search of females, but do notbite. After the prey istrapped in the web, the black widow makes small punctures in the victim'sbody and sucks out the liquid contents (Royo, 1997). After insemination, the male usually lingers on thefemale's web until she eats him. Black widow spiders belong to the family Theridiidae, which means theyare web weavers. The widow spiders.Http://hobospider.org/widows.html The black widow spidersare nocturnal, preferring a shaded, secluded resting place to spend most ofthe daylight hours if the web is constructed in an open area (Smith, 2 1). Bites by this spiderare a significant problem in some parts of its range, particularly inHerzegovina, where it commonly bites farm hands during harvest time. If the female is well-fed, the male maygo away to mate with another female. The male pedipalps (biting appendages at the front of the head)are noticeably swollen (National IPM Network, 2 1) Many people arebitten by the southern black widow, particularly in the southern regions ofits range, where it is most commonly found (Vest, 1999). (1997). K. The webs they spin lack the shape and form of otherspiders (Royo, 1997). The female spinsup to 8 round balls of web for her eggs. Thisprocess can account for large numbers of black widow spiders being found inone location (outbreaks of infestations) if the prevailing winds carry manyof the spiderlings in the same direction. After this prolonged courtship and mating ritual, the female then laysfrom 25 to 7 eggs in from four to 9 egg sacs during the summer (Royo,1997). Less than one percent of bites fromblack widow spiders are fatal. Spiderlings contain a poisonoussubstance in their body tissues until they are about 18 days old, and thiscan be toxic to pets and children (Oi and Shelton, 1997). All spiders are predators, and they feed on a variety of insects andother soft-bodied invertebrate animals (Akre, Catts and Antonelli, 2 1).Spiders attack and subdue their prey by biting them with their fangs andinjecting them with poison. Spiders are arachnids, a group of arthropods which includes scorpions,harvestmen, mites, and ticks (Akre, Catts and Antonelli, 2 1). R. M., & Shelton, T. The female rarely moves far and hangsfrom the web suspended upside down (Royo, 1997). The redback is black with a distinct red marking on its dorsal abdomenwhich can sometimes appear pink or light grey in color (Crew, 2 1). Acaptive spider can be made to produce silk by tickling the spinnerets atthe bottom of the abdomen and collecting the silk on a drawing pick (Kanto,2 1). The young black widow spiders are colored orange and white when theyfirst emerge from the egg sacs (Royo, 1997). Theneurotoxin acts at the junction between motor nerves and muscles and on theperipheral nerve endings (Smith, 2 1). It prefers dark, cool places to build its web, such as outhouses,window wells, under well covers, and beneath trash. The bite of a black widow spider is poisonous, and the venom isinjected along with saliva (Oi and Shelton. The European black widow, Latrodectus mactans tredecimguttatus, is thecommon black widow spider of southern Europe (Vest, 1999). The majority of bites occur on the hands andfeet. The female black widow spider stores sperm, and so is able toproduce more egg sacs without mating again (eNature, 2 1). The hourglass shapeof the northern widow's markings is usually divided into two separate,elongate markings. Female black widowspiders' webs contain a pheromone that identifies her to the male. The fly needs some of the spiderlings to survive so theycan dissolve an exit hole in the sac so the newly hatched flies can escape. Spiderling toxinis different from the venom of the adult black widow spider. The black widow is preyed upon by the mud-dauber wasp, which hunts thespider to feed its young, and a small fly, Pseudogaurax signatus, whichlays its eggs in a partially completed spider egg case (Smith, 2 1). It is blackwith a series of red markings on the dorsal abdomen. G. (2 1). Most bites occur accidentally when the spider is trapped against theskin, such as when they are in clothing that is put on, or are picked upwith rubbish (Crew, 2 1). A peculiarity about a bite from a redback isthat the limb which is bitten may sweat profusely while the rest of theskin remains dry. The redback spider, Latrodectus mactans hasselti, is found throughoutAustralia, except in the hottest deserts and on the coldest mountains andsome southeast Asian countries, and a similar species is found in SouthAfrica (Crew, 2 1; Vest, 1999). The appearance of the western widow is very similar to that of thesouthern widow, although its body markings are almost a perfect hourglassshape, divided into two separate spots in some specimens. Whenthe egg sac is finished, the fly larvae hatch and feed on the black widowspider's eggs. The venom attacks all the nerves of the body and can causeparalysis leading to death. The markings may also be white (eNature, 2 1). K. This comb-like structure is used tocreate the characteristic tangled web of the black widow spiders, and ofthe domestic cobweb spiders found in many houses throughout the UnitedStates. The young adults overwinter in buildings or insheltered dark places outdoors (National IPM Network, 2 1). Spiderlings that survive are dispersed to different areas throughballooning. Spidershave jointed legs and a hard external or outer skeleton. The black widow spider webs are an irregular tangled mesh built indark spots sheltered from the weather. A spiderling can be carried formany miles on this silken web (Smith, 2 1). The lifespan of the female isapproximately one and a half years; the lifespan of the male is muchshorter, since the female usually devours him after mating. Black widow spider.http://ipmwww.ncsu.edu:815 /AG369/notes/black_widow_spider.html Oi, F. The female southern black widow spider has a glossy black body,densely covered in microscopic hairs, and with a characteristic redhourglass shape on the underside of the abdomen (Crew, 2 1). S. Small children and the elderly are at thegreatest risk (Lyon, 1997). All spiders are poisonous (Akre, Catts and Antonelli, 2 1), but mostspiders are too small or have poison that is too weak to affect humans.However, the few spiders whose bites are dangerous to humans can causesevere medical problems, and even death. (2 1). Theyweigh approximately one ounce. During thegrowth phases (instars), the females molt from six to 8 times and the malesfrom three to six times (Royo, 1997). Black widow spider.http://www.ext.vt.edu/departments/entomology/factsheets/blackwid.html eNature. Black widow spider.http://www.enature.com/fieldguide/ShowSpeciesSH.asp Kanto, V. L. Black widow spiderhttp://ohioline.osu.edu/hyg-fact/2 /2 61A.html National IPM Network. One of its favorite places to build a web is inabandoned rodent holes. Thecolor varies with the species (Kaston, 2 1). The venom is aneurotoxin that causes a dull pain and cramping in the muscles. The webs usually have a funnel-shaped retreat (eNature, 2 1). The western black widow, Latrodectus hesperus, ranges from the extremenorthwest of Canada, south into Mexico, and east to west Texas (Vest,1999). The bite of the redback spider can result in serious illness andeven death. If this happens, the respirationbecomes thoracic. Latrodectus mactans is found in most warm areas ofthe world; Latrodectus geometricus is found in Africa; Latrodectuscuracavensis is found in the Americas; and Latrodectus hystrix, Latrodectusdahli, and Latrodectus pallidus are found in southern Europe, northernAfrica, and southeastern Asia (Royo, 1997). References Akre, R. The black widow spiders are approximately one inch to one and a halfinches in length and span from one inch to three inches (Royo, 1997). (1999). The spiderholds the thread stretched out between its hind legs, and when it isdisturbed again, it wraps the thread around the attacker. Prey is caught in thewebs, and includes a variety of insects such as cockroaches and beetles,and other arthropods. (1996). The male isabout one third the size of the female, and is harmless. The legs ofthe male are much longer in proportion to the body than those of thefemale. There are five species inthe United States, one in southern Europe, and additional species inAustralia, the Near east, and South America. L. It's preferred locale is secluded woodedareas, stone walls, tree stumps, and similar habitats. It hasbeen used to make the transit cross-hairs in a telescope, because it isthin enough to make the cross-hair needed to keep a star image from beingrendered invisible (Kanto, 2 1). It is often found inwood piles, and carried into the house with wood for the fire (Day, 1996).It is also found under eaves and in meter boxes. Like thesouthern black widow spider, the male of the species is smaller than thefemale, and its abdomen is elongate with white and red markings on thesides (eNature, 2 1). This causes progressive musclepain and incapacitation, including respiratory distress because of severechest pain. Pain may spread to the abdomen, and the abdominal muscles maybecome very rigid in extreme case. Unlike the southern and western widows, the northernwidow is most common in the northern part of its range (Vest, 1999).Although it is just as venomous as the other two widows, the northern widowdoes not seem to bite humans very often. Convulsions may occur, especially in children (Smith,2 1). The most dangerous spiders tohumans in North America are the black widow spiders. West Virginia UniversityExtension Service.http://wvu.edu/~exten/infores/pubs/pest/hpm7 4.pdf Royo, A. They continue to grow into adults during the spring andsummer. Some spin silk threads to aid in dispersal, the threads beingcarried by the wind to transport spiderlings away from their home web.These are known as balloon spiders. If the thread iswrapped around something like the nose of a mouse, the mouse will stop totry and remove it. Three types of black widow spiders are found in the United States(Vest, 1997). Black widow spider web silk is also usedfor making the cross-hairs in rifle sights (Oi and Shelton, 1997). However,if the females are well fed, the males may get away and be able to matewith another female (Lyon, 1997). Its legs are much longer in proportion to its bodythan those of the female. Black widow spiders.http://kaston.transy.edu/widow.html Lyon, W. It is the only dangerous spider withAustralia-wide distribution, and hundreds of people are bitten by redbackspiders every year (Crew, 2 1). The third type of black widow spider in the United States is thenorthern widow, Latrodectus variolus, which is found from the extremesoutheast of Canada, throughout the New England states, and south tonorthern Florida (Vest, 1999). Black widow spider silk for cross hairs on guidescopes. Small rodents sometimes try to prey on black widow spiders andoccasionally succeed (Smith, 2 1). The redback is not normallyaggressive, and if disturbed, will usually fall to the ground, curl up andfeign death. Black widows prey on insects (Royo, 1997). 1997). Sweating and vomiting can occur as well (Oi and Shelton, 1997).The pain usually reaches a maximum in from one to three hours, andgenerally goes away within 12 to 24 hours. The full designation for black widow spiders, according to Royo(1997) is: Genus: Latrodectus Phylum: Arthropoda Sub Phylum: Chelicerata Class: Arachnida Order: Araneae Sub Order: Labidognatha Family: Therididae Species: 6 The term "widow" comes from the fact that the females often devourthe males after or during mating (Vest, 1999). However, the silk of the black widow spider isstronger that of any other spider. (2 1). The black widow.http://www.aces.edu/department/ipm/BW.htm Powell, P. When it lands on anappropriate spot, it will construct its own web and begin its life ofcatching small insects for food. Most spiders construct silk egg cases to protect theireggs. Other symptoms include anxiety, restlessness, a feeblepulse, cold clammy skin, labored breathing, difficulty in speaking, a lightstupor, and delirium. The most well-known is the southern widow, Latrodectusmactans, whose Latin name translates as, "murderous biting robber." It isfound in the southeastern United States, west to central Texas andOklahoma, and north to southern New York. Black widow spiders.http://homepage.powerup.com.au/~glen/widow.htm Day, E. It is also found in the WestIndies. (2 1). Ballooning is a process whereby the young black widow spidersare dispersed by the wind (Powell, 2 1). D., Catts, E. Black widow spiders.http://www.desertusa.com/July97/du_bwindow.html Smith, R. However, when first disturbed by apotential predator, the spider retreats and spins a single silk thread thatcontains a large number of very sticky silk globules on it. Usually only one to 12 spiderlings survive after the 14 to 3 dayincubation period because of cannibalism among the young. It is so strong that it has been knownto snare small animals as large as mice (Oi and Shelton, 1997). The spiders are sexually mature 7 to 9 days after birth, and mate in the spring. P., & Antonelli, A. They are rarely found because of being eaten after mating. In most specimens thebody shape is rather like an anvil more than the typical hourglass shapeassociated with these spiders (Vest, 1999). (2 1). They have fourpairs of legs, and the body is divided into two sections, the cephalothoraxand the abdomen, whereas insects have six legs and their bodies are dividedinto three sections, head, thorax and abdomen. The egg sacsare about one half inch in diameter, and are suspended in the web. http://att.net/~n7wk/widpage.htm Kaston. "Black Widow" spiders.http://ag.arizona.edu/urbanipm/spiders/blackwidows.html Vest, D. Black widow spider. Themale approaches the female cautiously while sending out vibratory messagesto her through her web. This gives the spider time to escape. Fortunately, the serious effects of the venom takeseveral hours to days to develop, so there is time to get medical help andget the antivenom. All spiders spin silk, but not all of them useit to spin webs. The air currents carrythe spiderlings aloft on these webs as if they were flying kites. Some mildsymptoms may persist for several weeks after the victim has recovered fromthe initial reaction to the bite. If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.