Deer Task Force Report: Life-stages of the deer tick
It is common to hear comments that confuse the roles of deer and white-footed mice in sustaining deer ticks and Lyme disease. It is said that either species can sustain either population. However, their roles are separate; large mammals such as deer are necessary to sustain ticks and small mammals such as mice are necessary to sustain the disease.
The two-year life cycle of the deer tick (Ioxdes Scapularis) is depicted in the graph seen above. As a bearer of Lyme disease, ticks depend on two principal stages. In the first-year larval stage, ticks can acquire the Lyme bacteria (Borrelia burgdorferi) by blood feeding on infected small mammals such as white-footed mice. In the second-year adult stage, they need large mammals such as deer on which to feed on blood and lay eggs from which larvae hatch to complete the cycle.
In between the larval and adult stages, infected nymph-stage ticks can pass on the disease to humans or other animals, predominately from May through July. On Block Island, the existence of scrub brush is thought to enhance the transfer of adult ticks and eggs to and from the deer. More detail can be found on the internet by searching for information on the “deer tick life cycle.”
On Great Island, Mass., and Monhegan Island, Maine, deer were eliminated through managed hunting programs. The tick population collapsed and Lyme disease was virtually eliminated. Commenting on the situation on Block Island, the late Professor Andy Spellman of Harvard University, a deer tick and Lyme disease expert, said that “if you get rid of the deer, you will get rid of Lyme disease.”