Blacklegged Tick Common Name: Deer Tick
Blacklegged ticks are hard ticks, 1/16 to 1/8-inch long, and orange-brown except for the head, shield behind the head and legs which are dark reddish-brown. Their mouthparts are easily seen when viewed from above. Their bodies are flattened and shaped like a teardrop. The female’s shield-like area remains unchanged, but the rest of her body stretches and becomes darker as she engorges with blood while feeding. Blacklegged ticks do not have festoons (rectangular areas divided by grooves) along the posterior end of their abdomens. Unlike the adults, which have eight legs, the larvae have six legs and are 1/32-inch long. The eight-legged nymphs are 1/16-inch long when unfed.
During the winter moths the adults feed on deer. In the spring, engorged females drop off of the host animal and lay 3,000 eggs in a protected area. The eggs hatch in 48 to 135 days, and from June through September the larvae seek and feed on small rodents, such as mice, voles, and chipmunks. After molting to the nymphal stage, the ticks once again seek hosts and feed only once for three to nine days on larger animals such as raccoons, opossums, and squirrels. Nymphs are found from April through August of the following season. After 25 to 56 days, engorged nymphs molt to the adult stage, which usually feed on deer. Development- from egg to adult – is normally two years, but in the absence of suitable hosts, development can extend up to four years. Adults live long enough to mate and for the female to lay eggs and then die.
The blacklegged tick is found east of the Mississippi River. These ticks are three-host ticks, for example, they require different and successively larger host animals in order to complete development. The larvae and adults commonly infest white-footed deer mice and deer, respectively. However, the nymphs have a much wider range of hosts, including humans. It is this stage which responsible for the transmission of Lyme disease, the most significant tick-borne disease in the United States. Annually more than 10,000 people are infected with this disease, mostly in the northeast.
Blacklegged ticks climb grass and shrubs and wait for host animals. Typically they are concentrated in transition areas between fields and lower grassy vegetation, along animal trails, and in host animal nests and dens, such as woodpiles, burrows in the ground, stumps, logs old rat and bird nests, and crawlspaces.