Acarina

Acarina is the taxanomic subclass name for groups of parasitic insects that are most commonly known as mites and ticks. Mites and ticks are a very diverse species of arachnids and are very close to spiders. Mites and ticks are best known for their impact on crops and people. They are also the main carriers of lyme disease in America.

Anatomy
Ticks and Mites are both part of class Arachnida, having two main body parts, the cephalothorax (head and thorax), and the abdomen.They are very small and usually less then 10 millimeters across. They are not in any way segmented like spiders. Ticks are often confused with mosquitoes (Order Diptera). The segmentation is not external, and unlike other insects, mites and ticks never have antennae. All mites and ticks will also have four pairs of legs (8 legs total), although some adults have may three pairs of legs, and will grow their last pair (fourth) when they first moult.

Reproduction
Many species of mites and ticks reproduce in the same way, with there being two different ways. Mites and ticks are oviparous, meaning they lay eggs but usually do not carry them internally, instead depositing them upon a substrate where the female leaves them alone to hatch. Most species will reproduce sexually by connecting their genital regions and the male depositing his sperm in the female, this being the most direct method. Other species will reproduce asexually having the male indirectly place a drop of sperm on the females genitals with either his legs or mouth parts (Chelicerae)

Ecology
Mites and ticks have very different feeding preferences. Mites may be either carnivorous and eat very small invertebrates, while other mites may be herbivorous, eating agricultural plants and gardens, and more specifically, eat the plant sap these plants may contain. Ticks, on the other hand are more adapted to sucking and feeding on the blood of vertebrates such as humans and livestock. This feature of the tick confuses many people, and many people may confuse them with mosquitoes (Order Diptera), even though they cannot fly, but may still spread diseases in the same way. Mites and ticks live in just about every environment on earth. They are occasionally found in freshwater and marine environmetnts. Terrestial mites and ticks are usually found living in soil or dead leaves. Ticks are often not seen until removed from the host that they have atached themselves to.

Mites and Ticks Diseases
Mites and ticks are the leading cause of disease in the United states. The toxins, secretions, and small organisms found in the saliva are what cause the diseases in humans and animals. The tick or mite will most often transmit its disease near the end of its feeding once it has become full of blood. Once the tick is filled or mostly filled with blood it is easier to spot and remove, but it may have already transmitted its disease or virus. Hard ticks (Family Ixodiae) have a harder outside shell and will usually feed for more than a day before detaching. Soft ticks (Family Argasidae) will usually feed for less than an hour, and disease transmission from soft ticks can more than often occur in less than a minute. Additionally, the bite from soft ticks will often times instantly produce a painful itching spot at the location of the bite. Occasionally however the mite or tick will secrete a neurotoxin in its saliva before feeding that will destroy certain sensory nerves and will prevent the victim from feeling pain when the mite or tick does begin to burrow into the skin. The mite or tick may additionally release a chemical to thin the blood to allow more blood to get to the mite or tick quicker. The mouthparts of the mite or tick (chelicerae) are barbed, which greatly assist in its ability to burrow deep into the skin. Due to the victim not being able to feel the tick, the tick may be able to go completely undetected and may not transmit any disease at all, although this is unlikely. Others however, may be allergic to these secretions and will have a severe allergic reaction. The most common disease spread by ticks is lyme disease. Other diseases spread by ticks include Rocky Mountain spotted fever and Tularemia.