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Dermacentor andersoni Stiles, 1908
Rocky Mountain Wood Tick
Family: Ixodidae

Introduction to the Ticks of BC

Photograph

© Lars Karstad     (Photo ID #74165)

Map

E-Fauna BC Static Map

Distribution of Dermacentor andersoni in British Columbia in British Columbia

Introduction


This range of this tick species is the Rocky Mountains and it is established throughout central British Columbia, rare in coastal areas (Lindquist et al., 2016). It is common on horses, cattle, sheep and dogs (Lindquist 2016). This tick can transmit Rocky Mountain Spotted Fever.

Biological information presented below is taken from Gregson (1956).

Species Information

Gregson (1956) describes this genus as follows: “Ornate ticks with eyes and festoons. Anal groove posterior to anus. Basiacapituli of adults rectangular (of nymphs, triangular or rectangular). Palpi short and broad or moderate in width. Coxae I to IV increasing in size progressively. Coxa I bifid. Males with no ventral plates.” Higgins (1999) describes this species as just over 5 mm long, and easily spotted along trails where it is most frequently found, saying “they look like little brown seeds on the grass tips". Gregson (1956) indicates that this species may be separated from Dermacentor albipictus by its spiracular plates. He indicates that it has “moderately large goblets versus the larger ones of albipictus; and nymphs have the basis capituli drawn laterally into characteristic sharp points, the posterior margin of the basis and the scutum show a tendency to be pointed.”


Figures illustrating terms used in the description of ticks [PDF].

Biology

Species Biology

This species is found on a variety of hosts, including humans and dogs (Higgins 1999). Gregson (1956) states: '”In British Columbia the season of adult activity usually lasts from the beginning of March to mid-May, and reaches a peak in early April; east of the Rockies the active period may extend well into June. After these dates, adults that have not found hosts apparently enter a diapause by which ... a small portion are capable of surviving until the following season, some unfed adults may persist for a third season.” He reports the hosts for this species as including rabbits, marmots, cattle, sheep, horses, dogs, porcupines, goats, deer and bears, and also reports a prevalence of the species along trials, indicating a response to scent. When fully engorged, females are approx. half an inch long—males do take blood but don't become as engorged (Gregson 1956). He also reports the following: “The engorged females drops from the host and lays several thousand eggs ... larvae feed only upon small animals such as mice, ground squirrels, wood rats, chipmunks and marmots. ..; the life-cycle usually requires one to two years depending on the availability of hosts. Peak larval activity occurs in July, whereas the nymphs are active throughout the summer.” Higgins (1999) describes this species as “a three-host tick because it drops to the ground after each feeding and must find a new host before it can develop into the next stage.”

Source: Gregson, John D. 1956. The Ixodoideae of Canada. Canada Deapartment of Agriculture, Ottawa

Habitat


Gregson (1956) indicates that this species is found throughout dry bunch grass regions, with heavy concentrations found in areas of talus slopes near rocky bluffs. Higgins (1999) indicates that it is most abundant in grasslands, “but can be picked up anywhere east of the Coast Mountains and south of the Peace region.

Distribution

Range in Canada and BC

This is a common species in BC, and has been collected from many locations throughout the southern half of the province, including Adams Lake, Armstrong, Ashcroft, Big Creek, Birch Island, Boulder, Cranbrook, Burnaby, Cache Creek, Castlegar, Clearwater, Princeton, Creston, Douglas Lake, Kalden, Kelowna, Lilloet, Manning Provincial Park, Merritt, Nelson, Penticton, Richmond, Salmon Arm, Vaseaux Lake, and Vancouver. Higgins (1999) reports this as the tick species that people most often encounter in the Chilcotin-Cariboo.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
UnlistedUnlistedUnlistedUnlisted



BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Species References

Gregson, John D. 1956. The Ixodoidae of Canada. Canada Department of Agricluture, Ottawa.

Lindquist, Evert E., Terry D. Galloway, Harvey Artsob, L. Robbin Lindsay, Michael Brebot, Heidi Wood and Richard. G. Robbins. 2016. A Handbook to the Ticks of Canada (Ixodida: Ixodidae, Argasidae Biological Survey of Canada, Ottawa

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