Rocky Mountain Wood Tick
Introduction
The common name comes from its primary distribution being in the Rocky
Mountain states and the preferred habitat being the woods to
meadow/lawn transition zones. Although not a structural pest, the Rocky
Mountain Wood tick is the primary vector of Rock Mountain Spotted
Fever and also transmits the casual organisms of Colorado Tick Fever
and Tularemia; it also causes tick paralysis.
Recognition
Color brown, becoming grayish when engorged; scutum completely gray in
female, mottled brown and gray in male. Scutum restricted to front
half of dorsum in female, almost completely covering dorsum in male
except for festoons. Eyes on margin of scutum. Mouth visible from
above; rectangular with sides not laterally produced, about as long as
mouthparts; 2nd segment of palpi about as long as wide, not laterally
produced. Abdominal festoons 11 in number; anal groove present,
posterior to anus. Spiracular plate broad, with blunt process usually
reaching dorsum, goblets moderate in size and number.
Habits
Rocky Mountain wood ticks do not survive well indoors. If found
indoors, the tick probably was carried in on a pet or humans and dropped off
when fully engorged.
This is a three-host tick, with each stage requiring a different host.
These ticks typically crawl up on low vegetation and wait for a
host to pass. Larvae and nymphs feed mainly on rodents such as
chipmunks and ground squirrels. Adults are active on the ground during
sunny days, climbing up and down vegetation along large animal trails;
this means that not all adults will be caught on a tick drag. Adults
prefer large animal hosts such as cattle, sheep, deer, humans, etc.
Adult females insert their mouthparts into the host and feed until
fully engorged. However, males have a cycle of feeding for a short
time, withdrawing their mouthparts, hunting for a female and mating,
and then going back to feeding. Adults usually appear in late February
and are gone by July, with unfed adults gestivation and then
overwintering. Larvae feed throughout the summer. Nymphs may continue
to be present until late summer. Engorged larvae and nymphs, as well as
unfed adults, can overwinter.
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