INTRODUCTION.
These ticks get their common name from the single silvery spot located on the female's
dorsallupper surface at the tip/rear of the scutum (dorsal shield). Although not a
structural pest, lone star ticks attack humans more frequently than any other tick in the
eastern and southeastern states. It is of medical importance because it vectors the causal
organisms of tularemia, is a minor vector of Rocky Mountain spotted fever, may vector a
Lyme disease-like spirochete, and is a cause of tick paralysis. It occurs from
west-central Texas northward to northern Missouri and eastward to the Atlantic Coast; it
is especially abundant in the Ozark region and eastern Oklahoma.
RECOGNITION.
Unengorged adult female about 1/8" (3.2 mm) long, male slightly smaller (about
1/8"/2.9 mm); engorged female up to about 7/16" (I I mm) long, 3/8" (9.25
mm) wide. Body oval, dorsoventrally flattened (top to bottom). Color reddish brown,
becoming slate gray when engorged; scutum (dorsal shield) with single whitish to silvery
spot at its tiplrear in female whereas male with several inverted horseshoe- shaped
whitish spots along rear margin. Scutum (dorsal shield just behind mouthparts) restricted
to front half of dorsum in female, almost completely covering dorsum in male except for
festoons. Eyes on margin of scutum. Capitutum (mouthparts and their base) visible from
above; basis capituli (base for mouthparts) small, subrectangular; palpi much longer than
basis capituli, and slender with 2nd segment about twice as long as wide and not laterally
produced, 3rd segment much shorter than 2nd. Abdominal festoons (rectangular areas divided
by grooves along posterior margin) 11 in number, anal groove present, posterior to anus.
Coxa I (I st pair of logs) with external spur large and pointed, internal spur moderately
long, pointed. Next to last tarsal segment of 2nd- 3rd-4th legs lacking paired terminal
spurs.
Unengorged lst instar larva about 1/128" (0.2 mm) long, with 6
legs; 2nd instar nymphs about 1/16" (1.32 mm) long, with 8 legs.
SIMILAR GROUPS.
Gulf Coast tick (Amblyomma maculatum) with basis capituli triangular
dorsally, coxa I (lst pair of legs) with single spur, and next to last tarsal segment of
2nd-3rd-4th legs with 2 stout spurs near outer/distal end.
Cayenne tick (Amblyomma cajennense) has scutum with extensiv( pattern
of pale markings.
BIOLOGY.
The totally engorged female drops off the host and seeks a sheltered place t( lay her
eggs. After a preoviposition or waiting period of 5-16 days, she lays an egg mas.,
averaging 3,000-5,000 eggs (range few hundred to 9,000) over 7-23 days, and then dies Egg
hatch usually occurs in 21-50 days (range up to 117 days) depending on thf temperature.
Larvae (6-legged) attach to hosts which happen by, feed for 3-9 days t( reach engorgement,
and drop to the ground. They molt to nymphs (8-legged) in 13-4( days. After finding a
suitable host, nymphs reach engorgement in 3-8 days, drop off, an( molt into adults in
13-46 days. After finding a suitable host, adults mate on the host an( then feed with
engorgement requiring 6-24 days for females. Unfed larvae can survive ur to 279 days,
unfed nymphs up to 476 days, and unfed adults up to 430 days.
Egg laying begins in early spring by overwintered females and continues
into July Larvae peak in late July and August with late feeders overwintering as fed
larvae Nymphs emerging from late feeding larvae overwinter as unfed nymphs. Adults the
emerge after mid-July do not feed and overwinter. Larvae, nymphs, and adults enter ,
non-feeding period in mid to late summer which is apparently triggered by decreasin( day
length.
Lone star ticks are vectors of tularemia and a minor vector of Rocky
Mountain spotte( fever. Larvae have been found infected with the rickettsia of Q fever
(Query fever). Lymf disease-like spirochetes have been recovered from this species but its
vector status ha@ not been determined. This tick has also been implicated in causing tick
paralysis.
HABITS.
The lone star tick does not survive indoors. If found indoors, it was probable. carried in
on a pet or humans and dropped off when fully engorged.This is a 3-host tick, with each
stage requiring a different host. These ticks usuall,. contact a host by crawling up on
the tips of low-growing vegetation and waiting for a hos to pass by and brush the
vegetation. While larvae are almost entirely dependent on thi! behavior, nymphs and adults
may become stimulated by the warmth and carbon dioxide from a host spending considerable
time in the area and will drop to the ground, find tho host, and climb onto it.
Lone star ticks cannot survive long exposure to the sun and are
therefore typicall, found in shaded areas. The habitat must also contain both small animal
hosts for larval and large animal hosts for adults. A relative humidity of greater than
65% is required fo egg hatch and larval survival until host attachment. Favorite habitat
is the woods to lawl or meadow transitional zone.
Small animal larval hosts include gray fox (Urocyon), cottontail rabbit
(Sylvilagus) striped skunk (Mephitis), raccoon (Procyon), cotton rat (Sigmodon), gray
squirre (Sciurus), cat, and ground nesting birds including bobwhite quail and chickens.
Nymph@ get on many of these same animals as well as larger animals typical for adults. Adu
hosts include foxes (Urocyon), dogs, cats, cattle, white-tailed deer (Odocoileu,
virginianus (Zimmermann)), wild turkey, and humans. Humans are attacked by all stages.
Great care should be exercised when removing embedded ticks because
their lon@. mouthparts make removal difficult. The mouthparts are often broken off during
remove which typically results in secondary infection.
