Wikijunior:Bugs/Mite

What does it look like?

A dust mite.

Like all arachnids, mites have pincer-like mouthparts, four pairs of legs, and no antennae. Their two main body segments are fused together to make one large segment. Their color and body shape vary. They range in size from 1/64 inch to 1/8 inch.

All mites belong to the Order Acari. Scientists have described over 45,000 species of mites. Experts believe only 5% of all the different kinds of mites have been found.

Chigger mites are brownish or reddish in color. Some have a velvety surface. Their oval bodies are sometimes slightly pinched in the middle. They often have long hairs on the body and legs. There are 3000 species of chigger mites (family trombiculidae).

There are about 650 known species of spider mites (family tetranychidae). The color of these mites can be orange, red, green, or yellow. They have soft, rounded or pear-shaped bodies covered with fine pale hairs.

There are 120 species of scabies mites (family sarcoptidae). Also known as mange mites, they are small in size and pale brown in color. They have slightly flat round bodies with fine wrinkles and long fine hairs. They have short stout legs.

Adult housedust mites (family pyroglyphidae) are creamy blue in color and have a striped pattern on a rectangular shaped body.

Red velvet mites (family trombidiidae) can be as large as 1/16 inch long. The soft oval-shaped body is completely covered with a coat of fine red hairs. The front pair of legs is set forward like antennae. Hidden between a pair of stout palps are sharp mouth parts.

Where does it live?

Mites are found in various habitats throughout the world. Many species live outdoors in soil, leaf litter, and animal burrows. Others live on plants and animals. There are hundreds of species of mites that feed on bees inside hives.

Mites prefer warm moist surroundings. Beds, carpet and upholstery support high mite populations. Spider mites live in plants, trees, and shrubs. Scabies mites live in the skin or hair follicles of mammals, including humans.

Velvet mites are numerous in tropical regions. They are found in or on soil from savannas to forests. They often live in the litter of forest floors. Two-spotted spider mites are found in gardens, orchards, and greenhouses. Water mites live in ponds and slow streams. They crawl on immersed vegetation or swim through the water

What does it eat?

A favorite food of mites is human and animal dander (skin flakes). Most species of scabies mites leave tunnels when feeding on the epidermis (outer layer of skin). Chigger mites parasitize (feed on) humans, animals, reptiles, and birds.

Although red velvet mites appear to be sluggish, fluffy creatures, adults are actually voracious predators. They are capable of attacking and eating prey many times their size. Young red velvet mites are parasites on grasshoppers, locusts, and crickets.

Spider mites infest and feed on a wide range of plants. Two-spotted spider mites eat soft tissue and juice of American elm trees and house plants. House dust mites are not parasitic since they only eat dead tissue.

How does it defend itself?

Their small size allows mites to go unnoticed in dark places inside houses and on plants. They burrow into host surfaces and into soil where they are hidden from predators.

Spider mites live under leaves where they make protective webs. Two-spotted spider mite males shoot silk to ward off competitors.

What stages of metamorphosis does it go through?

Some mites give birth to living young, but most mite species lay eggs. Newly hatched young are called larvae. The larvae have only six legs. They grow two more legs after the first molt. Then they are known as nymphs.

Scabies mites mate on the skin of animal and human hosts. The eggs are laid in tunnels in the hosts’ skin. Females lay up to fifty eggs during their lifetime. Upon hatching, the young find shelter and food in hair follicles.

Chigger mites lay eggs in damp soil. The larvae climb grass blades to find passing hosts. While in the first stage, larvae feed on skin of mammals, birds, and reptiles. Later they penetrate the skin with sawlike chelicerae (jaws) to find fluid and tissue under the skin. When fully fed the larva drops off, molts, and finds small arthropods for prey.

Adult velvet mites come up from under the soil to mate and lay eggs. This often happens after a heavy rain. Some larvae feed on insects, such as grasshoppers while others feed on arthropods.

Varroa mites lay eggs in honeycomb cells where bees develop. The nymphs feed on bee larvae. When they become adults, they attach themselves to adult bees. They do this in order to feed and as a way of dispersing to other places.

What special behavior does it exhibit?

The tropical species Archegozetes longisetosus can lift over 1000 times its own weight.

Spider mites produce silk from glands at the front of their bodies.

Varroa destructor mites cannot reproduce unless they are inside a honey bee colony.

How does this bug affect people?

Dust mites are harmless to most people. They do not carry disease but they leave behind droppings that can cause allergic reactions. Symptoms can range from itchy eyes to asthma attacks. Unlike other kinds of mites, house dust mites are not considered parasites since they eat dead tissue.

Infestation by sarcoptes scabie mites causes extreme itching. Scratching leads to hair loss and infection. Sarcoptes scabie mites are the most common cause of mange.

Many spider mites are significant pests. They damage grasses and other plants. Infestations can seriously affect crops such as wheat, fruit, clover, cotton, and coffee. They cover plant parts with fine webbing causing the leaves to discolor and wither. Other pests that harm plants are thread-footed mites and gall mites.

Chigger mite bites cause severe itching, dermatitis, and allergic reactions. A few species transfer disease to humans.

Varroa destructor is a parasitic mite that attacks honey bees. It causes a disease called varroatosis. When it attaches to the bee’s body to suck juices, it spreads a virus that causes deformation of the bee’s wings. A serious mite infestation can cause an entire honey bee colony to die.

Many mite species are helpful to people. They attack insects and eat aphid eggs and roundworms.

References

http://www.ehso.com/ehshome/dustmites.php

http://www.ent.orst.edu/bugbook/taxons/Dolichothrombium.html

http://www.uky.edu/Ag/CritterFiles/casefile/relatives/mites/mites.htm

http://en.wikipedia.org/wiki/Mites

http://en.wikipedia.org/wiki/Varroa_Mites

McGavin, G. (2000). Insects spiders and other terrestrial arthropods. NY: Dorling Kindersley Inc.

Milne, L. & Milne, M. (1980). National Audubon Society Field Guide to Insects & Spiders. NY: Alfred A. Knopf, Inc.