Deer Tick Life Cycle

The only know transmitters of Lyme Disease in the U.S., deer ticks (or black legged ticks) in the east and western black legged ticks are hard-bodied with two year life cycles that consist of three stages:

STAGE-I: Larval -- Larvae hatch from eggs in summer and actively seek their first
blood meal in late summer.  No larger than a newsprint period, larvae are nearly impossible to detect. They contract Lyme only by feeding on infected hosts such
as common white tail mice, birds, chipmunks, squirrels, deer, etc..

STAGE-II: Nymph -- After feeding, larvae drop off hosts and molt in the fall. The resultant nymphs remain inactive through much of winter, becoming active in
April/May and seeking a host - mammal, bird, or human.  In New England, about
25% of nymphs carry Lyme Disease.  Between May and July the tiny nymphs
often attack and infect human hosts, who may not notice them because of their
tiny, poppy-seed size.

STAGE-III: Adult -- Nymphs fall off their hosts and into leaf litter to molt into adults.  They actively seek new hosts through fall, waiting, generally, for large mammals including humans, dogs, cats, horses, and deer.  Most active in October, November and early spring, 50% of adults have been found to carry Lyme Disease in New England.  When temperatures dip below 45 degrees F., ticks usually drop into leaf debris and become inactive; but as soon as temperatures rise, they resume their quest for hosts - usually in late February or early March.  By late March/early April, they are ravenous for a new blood meals, which they need to successfully mate
and reproduce.  Females drop off their hosts to lay about 3,000 eggs in the leaf layer and then die.  In late summer, these eggs hatch, beginning the tick life cycle anew.