Venom Of The Black Widow Spider example essay topic

Adult black widow spiders have a shiny, black, rounded, circular abdomen and are about 1/3 inch long (about 1-1/2 inches when their legs are spread). Adult spiders have two reddish or yellowish triangles on their bottom which looks like an hourglass marking, and their body color is dark colored usually black or sometimes dark brown. They are usually recognized because of their red or red-orange hourglass design on the bottom of their abdomen. This pattern is changeable and may look like two separated spots. In some spiders there is no pattern on the abdomen. The immature stages of both sexes of the widow spiders have red or red-orange or yellow spots and strips on the top of their abdomen.

Females are colored gray or pale brown. Their color gets darker as they get older. The hourglass pattern on the underside of the abdomen forms throughout their development. Male widow spiders are smaller about 1/4 inch long, and they " re usually not black in overall color, instead it looks like a light brown or gray. Male widows have an hourglass pattern too. When they are full-grown they have large knob-like shapes called, which start from the head.

But to females they still look the same. Newly hatched spider lings are white or a yellowish-white, eventually turning blackish when they get older. Adolescents of both sexes look like the male. Black Widow spiders build loose and uneven mesh-type webs of rough silk in dark places usually outdoors. And build their webs near the ground (sometimes inside of houses) but mainly they build them outside.

Black Widows can be found near the ground in dark undisturbed areas. Nest sites are near holes made by small animals, or around construction openings and woodpiles. Also they can be found around low shrubs which are usual sites for widow spiders. Black widows are also found inside in dark undisturbed areas like behind furniture or under desks and in undisturbed basement areas and crawl spaces of homes are areas where black widow nests are.

They don't produce a web like the weaving spiders do or the funnel pattern webs that the funnel weaver spider's make. The female lays eggs in silken cocoon sacs about 1/2-inch in width. The sack is a pear shaped, and is a creamy yellow, light gray, or light brown in color. They usually lay about 300 to 400 eggs per sac and have 4 to 9 egg sacs made during a summer. But only 1 to 12 young survive after the egg incubation period of about 14 to 30 days because of cannibalism. Growth requires 2 to 4 months depending on availability of prey during which the females shed 6 to 8 times and the males 3 to 6 times.

Females mature 92 days after the egg sac outburst and live for about 179 days, while males mature 71 days after outburst and live for 30 days. Because usually the female eats the male after they mate. But sometimes if females are well fed, the males get away to mate for another day. The females hang belly upward and very rarely leave the web. In cold weather and droughts it can cause these spiders to go into buildings. Prey caught in the web include a many different insects (cockroaches, fly's, and beetles) and other arthropods.

The female black widow is shy and usually only goes out at night. But when she leaves her web she usually goes far away from her the web. Outbreaks of black widows occur off and on. Some years an area may have thousands of widows and the next year they may be gone. Certain kinds of habitats such as sand dune areas may have black widows every year.

Alternating warm and cold weather during the winter and spring months are harmful to their survival. The venom of the black widow spider is 15 times as toxic as the venom of the prairie rattlesnake. However, only a small amount of the toxin is injected with a single bite by the spider, while the relatively large amount of injected rattlesnake venom results in about 15 to 25 percent mortality among those bitten. The severity of a person's reaction to the bite depends on where you were bitten, amount of venom injected and the depth of bite. When a black widow spider bits you it injects a toxin that affects the nervous system. At first, there may be only slight swelling and two faint red spots surrounded by redness at the bite.

Pain may be intense in one to three hours and could stay for up to 48 hours. Pain usually starts from the bitten limb up or down the arm or leg and then restrict in the abdomen and back. Also muscle and chest pain or tightness in those areas are some common reactions to a black widows toxin. The pain can also spread to the abdomen which causes cramping and nausea. The abdominal muscles may become stiff and board-like with severe cramps. There can be pain your muscles and soles of the feet and your eyelids may become swollen.

Other symptoms include restlessness, anxiety, breathing and speech difficulty, tremors, vomiting and sweating. Swelling can be noticed in extremities and eyelids but rarely at the place where you are bit. Also there is a sense of discomfort after you are bitten, and some symptoms increase in severity during the first day after you are bit. But symptoms usually get better after two to three days but some mild symptoms can continue for several weeks after you have recovered. The bite that is usually the most dangerous a female bite. Although it is very painful, fatalities from untreated black widow bites are uncommon.

During 1926 to 1943, death ranged from 4 to 5 percent, but current medical treatments have reduced this to a smaller percentage. Death usually results from respiratory paralysis. People with a history of high blood pressure are at the greatest risk. But immediate medical treatment can reduce the danger from widow bites and has reduced fatalities to very low rates in recent years.

However, this spider is considered the most venomous spider in North America. If you are bitten stay calm, get the spider, if you can for positive identification and because of the possible severity of black widow bites you should get immediate medical attention is important. If you apply an antiseptic such as iodine or hydrogen peroxide prevents infection. Physicians can inject calcium to help the effects of the toxin so it is less harmful. This helps support levels of calcium salts that are low by the effects of a bite. You can also get black widow antiserum.

Since the toxin moves quickly through the body trying to suck out the poison doesn't work. People younger than 16 and older than 60, especially those with a heart condition might have to stay at a hospital. The black widow spider is shy and usually not aggressive and bites can be rare even when there are lots of them. The adult female spiders usually stay in their webs unless they have to because of the temperature or if their web gets destroyed.

They do not search for food and they eat the insects they get in their webs and are eaten when they get to them. Human bites happen when the spider is defending their web if it is brushed against or accidentally pinched. Occasionally, bites occur from hungry widow spiders when a hand or foot is flopped in front of the nest. Before there was indoor plumbing bites were usual in outhouses, usually on the males genitals. To control the problem of black widows check areas in and around your home where black widows may be found.

If you find one it can be killed by crushing or vacuuming the wed and spider, using protective way. Increasing the amount of light in dark areas also can discourage spiders. Also insecticides can work for spider control but it doesn't control all spiders. If you do put down insecticide put it in the dark undisturbed areas where spiders are usually found. Insecticides also can be used to stop spider migrations into houses by spraying around the outside of the foundation and lower story windows.

Do it before cold weather because that forces spiders into homes to find protection. The insecticide is the most widely used product to control spiders around the house. Chlorpyrifos remain effective for several weeks if is not exposed to light and moisture. But pyrethrin is used specifically for black widow spiders. To help prevent anyone from getting harmed by black widows, you should tell everyone in your family to learn about black widows so they can identify and avoid them.

It is also a good idea to wear gloves and a long-sleeved shirt when working in spider infested areas. Remove trash, old boxes, piles of lumber, old rubble piles and other unwanted things from under or around houses and outbuildings. Do not go barefoot or handle firewood without gloves. Put up screens on doors and windows to prevent them from getting in. Seal or caulk cracks and crevices where spiders can get in the house. And wash off the outside of the house or building especially around window wells and other undisturbed places where they build webs.

There are also several other kinds of widow spiders. I listed them below and briefly gave you some information. Although there are three distinct species, they share similar physical and life-history characteristics. The adult female's body is usually 0.5 inch long, with a bright red marking resembling an hourglass on its underside. The male is much smaller, with a length of. 25 inch and about four bright red dot markings on its sides.

The male is shy and rarely seen by humans. The females are generally not aggressive unless they see a threat or are guarding an egg sac. All three species of black widow live in close proximity to humans, and each species shows a distinct preference for not only a specific habitat, but also its particular nesting area. The eastern black widow, which builds its web close to the ground, is found primarily in woodsheds and woodpiles, but it has also been found in parks, especially around the legs of picnic tables. The western black widow builds its nests higher up and is commonly found in gardens, especially on bushes, as well as in picnic areas, where it colonizes the undersides of picnic tables.

Although the western black widow is more commonly found in these somewhat natural areas, the species has also been discovered in highly urbanized locations. The northern black widow, while maintaining some proximity to humans, lives generally in undisturbed wooded areas, as well as around stone walls, trees, and tree stumps, and is almost never found associated with a house. The western black widow, Latrodectus hesperus ranges from extreme southwestern Canada, south into Mexico, and east to west Texas. Hesperus is the common black widow of the western United States, and it is abundant in areas of Arizona, California, and other westerly locations. One of the most commonly places where it is found is in natural habitats for example is in abandoned rodent holes, but it can also be found around peoples houses, even in the downtown districts of many western U.S. cities. The western widows general appearance is very similar to the southern widow it has the hourglass marking and is usually shaped like a perfect hourglass, but it is divided into two separate spots.

Like its southern cousin, the western widow it causes a large number of bites, mostly in the southern locations. The Northern Widow, Latrodectus various, is the third black widow found in the United States. It is found from extreme southeastern Canada, throughout the New England states, and south to northern Florida. It prefers undisturbed wooded areas, stone walls, stumps, and similar habitats. The 'hourglass' of the northern widow is usually divided into two separate, elongate markings. This species is most common in the northern part of its range.

While its venom is very similar to that of the southern and western widows, and bites do occur, it does not appear to bite humans as often as those species. The Red Widow, Latrodectus bishop i, is a U.S. species with a restricted range, being found only in palmetto fronds of sandy, scrub-pine regions of central and southern Florida. This spider is rather brightly colored, with red legs and cephalothorax (fore-part of the body), and a black abdomen with orange and white markings down the back and sides. The 'hourglass' usually consists a single red elongate marking.

Little is known of the bite of the red widow, but its venom is probably quite toxic to mammals. The Brown Widow, Latrodectus geometric us, is a species, found in most tropical seaports around the world; it is an introduced species in Florida. Coloration may vary, but is usually brown to grey, with white and black markings on the back and sides of the dorsal abdomen: The 'hourglass' is usually complete. This species is often found on or around human habitations and other buildings. While definitely venomous to humans, bites tend to be less severe than those of most other widow spiders. The Malmignatte or European Black Widow, Latrodectus mac tans, is the common widow spider of southern Europe (northern Mediterranean).

It is black, with a series of red markings on the dorsal abdomen. The is a significant medical problem in various parts of its range. In Herzegovina (the former Yugoslavia) this spider reportedly causes a large number of bites each autumn in field workers harvesting grain by hand. The red back spider, Latrodectus mac tans, is found throughout Australia, and in some Southeast Asian countries. It is black, with a distinct red (sometimes pink or light grey) marking on its dorsal abdomen. Like most widow spiders, it harbors a highly toxic venom, and is considered a species of clinical significance.

Similar species are found in South Africa. As for if it is currently facing any problems in its environment, no one knows their exact numbers but they are far from extinction, even if every spider was killed that was found by a person. And that is my report on the black widow spider.