Insect : around the world
Scorpions :
Scorpions belong to class Arachnida and order Scorpionida. They are unusual among arachnids as their young are born alive and carried about for a few days on the mother's back. Like all arachnids, scorpions have no antennae and the several small eyes are simple , not compound as in insects. Some African scorpions reach a length of 7 inches but the usual length is about 21/2 inches. The tail is held in position for stinging enemies and sometimes to subdue the insects and spiders that are the food of scorpions. To humans, the sting of most scorpions is merely painful. However , there are a few species, esp. in northern Mexico and northern Africa that inject nerve poisons and cause many fatalities a year in rural areas where antidotes are not quickly available.
Harvestmen:
Daddy-longlegs or Harvestmen belong to class Arachnida and order Phalangiida. The daddy-longlegs are identified with their height, very long, thread like legs and a tiny round body suspended in the air above them. The legs are easily lost, but the animal is able to get along without one or two. Daddy - longlegs are harmless and slow-moving. They eat small insects, living or dead, but never become pests. They are not spiders and do not spin webs . Some have stink glands, which give off a liquid to repel enemies.
Mites:
Mites are seldom seen by the average person. They are extremely important and numerous too. Mites cause econimic damage to fruit and vegetables crops and ornamental plant; the "red spiders" on house plants are actually mites. The parasites such as chiggers burrow under the skin or feed externally on mammals, birds and insects. Some of the animal parasites carry diseases, like scrub typhus. Mites occur in every environment : arctic , temperate,and tropical and some time even in salt water and hot springs. Like a tick , a mite's body is a single unit , with no apparent neck or waist. Adults have eight legs, and there are no wings or antennae . Most mites are smaller than a pinhead, but some brightly coloured ones may be as large as a lemon seed."Beetle mites" superficially resemble tiny beetles and are scavengers in soil and under bark everywhere. They break down organic matter and thereby fertilize the soil. Many other kinds of mites have developed bizarre shapes which have been adapted for living on their hosts.
Ticks :
Ticks are external parasites of mammals , birds or reptiles. They suck blood after thrusting the mouthparts throughout the skin of their hosts. After the meal, which may last several days, the ticks drop off, molt; then climb onto the tips of leaves of underbrush, to await a new host. Although bereft of antennae or acute eyes , they sense when a host is near by detecting the exhaled carbon dioxide. When the host brushes against them, they attach themselves. They lay eggs in various places, but not on the host. Several kinds of ticks are medicinally important because they transmit diseases such as relapsing fever, spotted fever , tularemia, and cattle fever. Among the most familiar ticks are the wood ticks that infest humans in many parts of North America, and the brown dog tick, which is cosmopolitan. The dog tick is often carried into houses on dogs, but it rarely bites people.
Orb-Weaver :
Orb-Weaver are gifted weavers. The classic spider web pattern seen in folk and fine arts is the type so elegantly crafted by Orb-Weavers - a spiral woven on strands radiating from the centre and all in one vertical plane. This family of 2500 species is worldwide. They have poor vision, but have an acute sense of touch. When insect prey is caught in the web, the orb-weaver rushes out, trusses the victim in strands of silk and dissolves out its juices. Spiders cannot swallow solid food.
Jumping spiders are short-legged . They can pounce on the insect prey from a distance many times their own length. They are daytime predators and have better eyesight than most other invertebrates. They are almost mammal-like in their alertness and behavior. No webs are woven but a strand of web is often used the way a mountain-climber uses a rope. This family includes the most colourful spiders, with beautiful patterns and some iridescence. Jumping spiders are usually less than 710 inch(15 mm). Most of the 2800 species live in the tropics, but they are common in North America and Eurasia too.
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