Ticks Arthropoda

Ticks are not insects. Along with mites, spiders and scorpions (class Arachnida), they belong to the order of arthropods know as Acarica. They do not have wings and cannot fly. They are important vectors of disease across much of the United States and around the world. Ticks have three characteristics which distinguish them from insects. 1. Ticks have two body parts. The head and thorax are fused together to from one body part called the cephalothorax, and the second body part is the abdomen. Insects have three body parts: the head, the thorax and the abdomen.) 2. Adult ticks have eight legs (adult insects have six legs). 3. Adult ticks have no antenna (adult insects have a paid of antennae on their head). When ticks bite, they usually remain attached to their hosts long enough to inject large amounts of saliva. Depending on the species of tick involved and how long it bites, the symptoms can range from mild skin irritation to paralysis. When we say that ticks bite we mean that it inserts its mouthparts into the host and sucks blood. The size of ticks varies considerably depending on the type of tick (family, species, sex, etc) and the stage of its life history. Ticks rarely however exceed three fourths of an inch in length when fully engorged. The fully engorged tick resembles the size and shape of a bean. (The term "engorged" means that it has fed upon its host and that it is full of blood.)