Rocky mountain wood tick

Definition

A hard tick species, Dermacentor andersoni (family Ixodidae), native to the western United States and southwestern Canada, where it inhabits brushy montane and subalpine habitats. Adults parasitize large mammals including humans, livestock, and wild ungulates; larvae and nymphs feed on small mammals. The species is a primary vector of Rocky Mountain spotted fever (Rickettsia rickettsii), Colorado tick fever virus, and tularemia (Francisella tularensis), and causes tick paralysis through neurotoxins in its saliva.

Etymology

English common name refers to its Rocky Mountain distribution and woody, brushy habitat preferences; scientific epithet honors American entomologist Charles Anderson.

Example

In the Bitterroot Valley of Montana, peak adult activity of Rocky mountain wood ticks occurs from March through June, with diurnal questing behavior on vegetation up to 75 cm above ground.

Synonyms

• Dermacentor andersoni

Related Terms

• hard tick
• Tick paralysis
• Rocky Mountain spotted fever
• Colorado tick fever
• questing behavior
• Dermacentor
• Vector
• tick-borne disease

Usage Notes

Often confused with the American dog tick (Dermacentor variabilis), which occupies overlapping eastern ranges; distinguished by more ornate scutal patterning and more northern/western distribution. Seasonal activity is earlier than many ixodid species, with adults active in spring rather than summer. The common name is sometimes written without capitalization of 'mountain' in non-technical contexts, but standard field guides prefer 'Rocky Mountain'.