Ticks thrive on blood obtained from the host. They are subdivided into hard and soft ticks according to structural characteristics.

Hard Ticks

The bodies of hard ticks are roughly oval in shape and pointed at the front. The anterior segment is a false head, or capitulum; the shape of its base is characteristic of the particular tick genus. Structures in the capitulum may also help to identify the tick genus. Palps are segmented structures used for probing the host. The hypostome anchors the tick to the host's skin, and mouthparts on the capitulum are adapted for sucking blood.

The abdomen flattened top to bottom, can expand to several times its original size as the tick feeds on its host. This phenomenon, referred to as engorgement, is seen only in females. One part of the skin, the scutum, located on the back of the tick, does not expand during engorgement. In some species, the scutum may be decorated with coloured pigments. These patterns of pigmentation may help with identification. Male ticks are generally more colourful than females in ornate (coloured) species. The presence or absence of other structures may also help to identify ticks.

A further classification of hard ticks is made according to whether their life cycle involves one, two or three hosts. This is described under the section on life cycles.

Soft Ticks

Soft ticks differ from hard ticks in several respects. They have a leathery outer skin rather than a hard cuticle, and both males and females engorge when feeding on the host. Their shapes vary among species. There is no scutum, and the capitulum is located on the bottom side of the tick near the its front. Otobius megnini, the spinose ear tick, is a soft tick. Only larvae and nymphs of this species are parasitic. Adults live in hidden areas in the environment, such as within cracks in the wood of barns.

Ctenocephalides

Glossary