Spiders


My essay is on spiders. I have chosen a few spiders to report about. I
also have some basic info about spiders in general. Spiders comprise a large,
widespread group of carnivorous arthropods. They have eight legs, can produce
silk, and usually have poison glands associated with fangs. More than 30,000
species of spiders are found on every continent except Antarctica in almost
every kind of terrestrial habitat and a few aquatic ones as well. Spiders range
in body size from about 0.5 mm (0.02 in) to 9 cm (3.5 in). The term spider is
derived from the Old English spinnan ( "to spin" ) referring to the group\'s use
of silk. Spiders make up the order Araneae in the class Arachnida, which takes
its name from the mythological character Arachne, a peasant girl who challenged
the weaving skill of the goddess Athena. Arachne equaled Athena\'s skill in a
contest, and in response to Athena\'s anger she hanged herself. In belated
remorse Athena changed the body of Arachne into a spider and allowed her to
retain her weaving skill.

My first selection is the brown recluse spider. The brown recluse spider
(Loxosceles reclusa) is a poisonous spider in in the United States. Its mostly
found from Kansas and Missouri, south to Texas, and west to California. Found
in sheltered places indoors and outdoors it is about 10 mm (.4 in.) long and
has an orange-yellow body with a dark violin-shaped design on its back. Its
bite isn\'t usually fatal to humans, the venom destroys the skin and it may take
a few months to heal. The brown recluse is mostly active at night. it feeds on
small insects that it paralyzes with its poison.

The Black Widow

The black widow, Latrodectus mactans, is a poisonous spider of the
family Theridiidae, order Araneida. The female, about 1.3 cm (0.5 in) long, is
glossy black, densely clothed with microscopic hairs, and has a red hourglass
mark on the underside of the abdomen.
The male, which is rarely seen, is smaller than the female and has four
pairs of red marks along the sides of the abdomen. The black widow is found
worldwide in the warmer regions in every state in the United States except
Alaska and Hawaii; it lives in a variety of natural and domestic habitats.
Generally, the females are not aggressive unless agitated, although they are
prone to bite when guarding an egg sac. The venomous bite of the black widow
spider, Latrodectus mactans, causes muscle spasms and breathing difficulty in
humans and may be fatal. The female is distinguished by a red hourglass marking
on its underside. The black widow eats a diet of insects, spiders and centipedes
captured in its web. After mating, the female may ensnare and feed upon her
mate--hence the name black widow. Itís venomous bite causes muscle spasms and
difficulty in breathing.

Tarantulas

In common American usage, tarantulas are the large, hairy long-lived
spiders that make up the family Theraphosidae. Related forms such as funnel-web
spiders and trap door spiders are also often called tarantulas. The name came
from a smaller wolf spider of Europe but was then applied by explorers of the
New World to the giant spiders that they encountered. No North American species
has a venom that is dangerous to humans, but tarantula body hairs may induce an
allergic reaction. Tarantulas can give you a painful bite. Tarantulas occur in
warmer regions, where they feed on both invertebrates and small vertebrates.
Many grow to about 2.5 to 7.5 cm (1 to 3 in) long, with a 13-cm species (5-in)
legspan, and some South American bird-catching species are larger. Some
tarantulas reach an age of 20 years.

Category: Science