Western Black-legged Deer tick

Ixodes pacificus  (Ix. scapularus for Eastern species)

Host Type: 3-Host Tick

Tick ID

** For detailed photos along with descriptions: https://www.inspq.qc.ca/en/detailed-description-ixodes-scapularis-or-black-legged-tick-or-deer-tick

ADULT FEMALE

Head

  • Basis capituli rectangular.
  • Long palps (palps are longer than the basis capituli).

Abdomen

  •  Partial shield, oval, dark and inornate (uniform color – without light spots).
  • Absence of eyes.
  • Presence of genital pore.
  • Anal groove above the anus.
  • Absence of festoons, unlike ticks belonging to other genera (Dermacentor, Amblyomma, Rhipicephalus and Haemaphysalis).

ADULT MALE

Head

– Basis capituli rectangular.
– Short palps.

Abdomen

  • Complete shield, inornate (uniform color – without light spots).
  • Absence of eyes.
  • Presence of genital pore.

NYMPH STAGE

Head – same as adult female

Abdomen

  • Oval shield, inornate (uniform color – without light spots).
  • Absence of eyes.
  • The nymph stage differs from the female stage by the absence of a genital pore.
  • Anal groove above the anus.

Most abundant in summer, and carry Lyme commonly

LARVAL STAGE

Head – same as adult female

Abdomen

  • Oval shield, unornamented (uniform colour – without light spots).
  • Absence of eyes.
  • The larval stage differs from other stages in that the larva has only 3 pairs of legs and not 4 like all the remaining stages.
  • Presence of only 3 pairs of legs.
  • Unable to transmit Lyme disease bacteria.

Diseases it can transmit 

Lyme Disease (Borrelia burgdorferi & Borrelia mayonii), Anaplasmosis (HGA), Powassan virus.  

Distribution in United States