Lone Star Ticks
Order: Acarina
Family: Ixodidae
Scientific Name: Amblyomma americanum (L.)
The
lone star tick, Amblyomma americanum,
is generally southern in distribution.
Its range extends from central Texas north through Oklahoma and
Missouri, and along the East Coast as far north as New York.
Lone star ticks can feed on humans during any of its three developmental
stages: larva, nymph and adult.
This species is a vector of tularemia and Rocky Mountain spotted
fever, and is suspected of being involved in the transmission of Q fever
and Lyme’s disease.
It is also one of four ticks most often associated with tick paralysis,
a condition caused by a neurotoxin injected during feeding that leads
to ascending paralysis, that is, from the legs upward.
If the tick is not removed, this paralysis can result in death.
Identification
The lone star tick is classified as a hard tick. It has a dorsal shield (scutum) which is immediately behind the false head (capitulum), and its mouthparts are visible from above, causing the tick to appear tapered anteriorly. In contrast, a soft tick does not have a dorsal shield, and its mouthparts are not visible from above, giving it a blunt appearance anteriorly. The genus Amblyomma is distinguished from other hard tick genera by eyes located on the lateral margins of the scutum, and long mouthparts (palpi) that have a second segment at least twice as long as it is wide. They also have tab-like markings (festoons) at the posterior edge of the body.
These
ticks have four life-cycle stages: egg, larva, nymph and adult.
Adult females have a reduced scutum with a distinctive white spot
on its posterior tip.
In contrast, the male scutum covers almost the entire dorsal surface
and has inverted horseshoe markings at its posterior edge.
As with all ticks, the nymph has eight legs and the larva has six.
Life Cycle and Habits
Amblyomma americanum is a three-host tick, that is, each life stage requires a blood meal for development. Each life stage usually takes a meal on different host animals. Adults feed primarily on large mammals, such as cattle, deer and coyotes, but can feed on medium-sized ones, such as foxes, skunks and dogs. Birds and small mammals are very common hosts for nymphs and larvae, but larvae do not feed on small rodents.
Engorged
females drop off their hosts from April through early June.
After five to 16 days, they begin depositing egg masses, which
can contain over 5,000 eggs, under leaf litter.
Larvae hatch in 30 days and crawl up tall grass in shady areas
to wait for a host. As many
as 90 percent of the larvae die due to various environmental factors. Larvae feed for 3 to 10 days; after feeding, they require 12
to 43 days to develop into nymphs, and can survive 2 to 9 months without
another blood meal. Nymphs
feed for 3 to 10 days; after feeding, they require 14 to 51 days to develop
into adults, and can survive 4 to 15 months without feeding.
Adults have similar survival rates as nymphs. Females generally feed for 6 to 14 days.
Control
Control of lone star ticks involves personal protection, vegetation management, host management and area-wide acaricide application. The best solution to tick problems is avoiding tick-infested areas. PCOs entering tick-infested areas should wear proper clothing and use skin and clothing repellents. Check pets frequently for ticks and immediately remove those found. Keep vegetation cut back to reduce the ticks’ ability to locate a host. Management of wild host animals also reduces the likelihood of having a problem with these ticks.
Depending
on when applied, acaricide applications using liquid or granular formulations
target different life stages: from late April to early June, overwintering
populations of nymphs and adults; from July to early September, new larvae;
and from August to September, mixed populations.
Lone star ticks do not establish populations indoors and are rarely
a problem there.
(Courtesy of the National Pest Control Association.)