Ticks, Suborder Ixodida

The parasitic arachnids we call ticks all belong to the suborder Ixodida. The name Ixodida derives from the Greek word ixÃ… dÄ“s, meaning sticky. All feed on blood, and many are vectors of diseases. Description: Most adult ticks are quite small, the largest reaching about 3mm in length at maturity. But when engorged with blood, an adult tick can easily expand to 10 times its normal size. As adults and nymphs, ticks have four pairs of legs, like all arachnids. Tick larvae have only three pairs of legs. The tick life cycle has four stages: egg, larva, nymph, and adult. The female lays her eggs where the emerging larva is likely to encounter a host for its first blood meal. Once fed, it molts into the nymph stage. The nymph also requires a blood meal, and may go through several instars before reaching adulthood. The adult must feed on blood a final time before producing eggs. Most ticks have a three-host life cycle, with each stage (larva, nymph, and adult) finding and feeding on a different host animal. Some ticks, however, remain on a single host animal for their entire life cycle, feeding repeatedly, and others require two hosts. Classification: Kingdom – Animalia Phylum – ArthropodaClass – ArachnidaOrder – AcariGroup - ParasitiformesSuborder - Ixodida Habitat and Distribution: Worldwide, there are nearly 900 species of ticks known and described. The vast majority (about 700) of these are hard ticks in the family Ixodidae. Approximately 90 species occur in the continental U.S. and Canada. Major Families in the Order: Ixodidae – hard ticks Argasidae – soft ticks Genera and Species of Interest: Both the blacklegged or deer tick (Ixodes scapularis) and the western blacklegged tick (Ixodes pacificus) can transmit the bacterium that causes Lyme disease.Proteins in the saliva of the Rocky Mountain wood tick, Dermacentor andersoni, can cause paralysis in its hosts, which include cattle, horses, dogs, sheep, and humans. Boophilus ticks are parasites of large hoofed mammals, and complete their life cycle on a single host. Amblyomma nuttali holds the record for the largest clutch of eggs produced by a single tick – over 22,000! Sources: Borror and DeLongs Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.Synopsis Of The Described Arachnida Of The World, Texas AM University Entomology Dept. Accessed online December 31, 2013.The Encyclopedia of Entomology, 2nd edition, edited by John L. Capinera.The Distribution of Ticks, Centers for Disease Control. Accessed online December 31, 2013.Order Ixodida – Ticks, Bugguide.net. Accessed online December 31, 2013.Tick Biology, the Tick App, Texas AM University Entomology Dept. Accessed online December 31, 2013.