How do ticks overwinter? - briefly
Ticks survive winter by entering diapause and locating insulated microhabitats such as leaf litter, soil, or animal nests, where reduced metabolism conserves energy. They remain inactive until ambient temperatures rise and hosts become active again.
How do ticks overwinter? - in detail
Ticks must survive periods of low temperature and limited host availability to complete their life cycle. Survival depends on selecting microhabitats that buffer against freezing and desiccation, entering a state of reduced metabolic activity, and employing biochemical mechanisms that protect cellular structures.
Common overwintering tactics include:
- Remaining attached to a mammalian host throughout winter, exploiting the host’s body heat.
- Dropping into leaf litter, moss, or soil where insulation and moisture are higher.
- Seeking refuge under bark, in rodent burrows, or within bird nests, where temperature fluctuations are minimal.
Physiological adaptations that support these tactics are:
- Synthesis of antifreeze proteins that inhibit ice crystal formation within tissues.
- Accumulation of glycerol and other polyols that lower the freezing point of body fluids.
- Modification of cuticular hydrocarbon composition to reduce water loss.
- Initiation of diapause, a hormonally regulated suspension of development, which conserves energy reserves.
Environmental variables that influence winter survival are:
- Humidity levels; high moisture prevents lethal dehydration.
- Soil and litter depth; greater depth provides thermal stability.
- Presence of host animals; continuous blood meals eliminate the need for prolonged dormancy.
These strategies enable ticks to re‑activate in early spring, resume questing behavior, and resume pathogen transmission cycles. Understanding the mechanisms of winter endurance informs predictive models of tick population dynamics and associated disease risk.