Blacklegged tick (Ixodes scapularis) surveillance

Estimated distribution of areas where the blacklegged tick (Ixodes scapularis) could survive and reproduce (yellow), and counties where established populations have been documented (red). Counties classified as “established” are those where six or more I. scapularis of a single life stage or more than one life stage of the tick were collected in the county within any 12-month period. Counties not classified as established should not be interpreted as the tick being absent.

Blacklegged tick (Ixodes scapularis) lifecycle

Ixodes scapularis typically lays eggs in the spring. These hatch into larva in summer. The following spring, nymphs feed and then molt into adults later in the fall. Adults females will seek a blood meal and lay eggs the following spring, completing the lifecycle.

The lifecycle of blacklegged (Ixodes scapularis) ticks generally lasts at least two years. During this time, they go through four life stages: egg, larva, nymph, and adult. After the eggs hatch, the ticks must have a blood meal at every stage to survive. Blacklegged ticks can feed from mammals, birds, reptiles, and amphibians. The ticks need a new host at each stage of their life.