Spiders Essay

416 WordsJul 23, 20122 Pages
Introduction Spiders are small, eight-legged creatures that are best known for spinning silk webs. Spiders spin webs so they can catch insects for their food and even larger and stronger insects cannot escape. All spiders spin silk but some don't spin webs. Bolas spiders spin a single line with a sticky end. Any insect near, gets trapped when the spider swings the sticky line near them. Identification Red back spiders (Latrodectus Hasselt) belong to the Family Theridiidae, which is found worldwide. The notorious Black Widow Spider (Latrodectus sp) of the United States is a close relative of the Red back Spider, and only differs in appearance by the absence of a red dorsal stripe. Other species of Latrodectus occur in Africa, New Zealand (the Katipo), the Pacific Islands, Europe and North and South America. Female Red back Spiders are black (occasionally brownish) with an obvious orange to red longitudinal stripe on the upper abdomen, with the red stripe sometimes being broken, and an "hourglass" shaped red/orange spot on the underside of the abdomen. Juveniles have additional white markings on the abdomen. Females have a body about the size of a large pea and slender legs. The males' red markings are often less distinct. The body is light brown with white markings on the upper side of the abdomen, and a pale hour-glass marking on the underside. Distribution They are found Australia-wide and will live almost anywhere as long as there is adequate food, a sheltered web site and warm enough for breeding. They are especially common in disturbed and urban areas, in association with human habitation. Habitat Webs consist of a tangled, funnel-like upper retreat area from which vertical, sticky catching threads run to ground attachments. The Red back Spider favours proximity to human habitation, with webs being built in dry, sheltered sites, such as among rocks, in

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