When are ticks inactive? - briefly
Ticks become dormant when temperatures drop below about 10 °C (50 °F) and humidity declines, conditions common in winter months. During this period they enter diapause and resume activity as temperatures and moisture levels rise in spring.
When are ticks inactive? - in detail
Ticks cease active questing when environmental conditions fall below physiological thresholds. Temperature is the primary driver; most species stop seeking hosts below 5 °C (41 °F). At such low temperatures metabolic processes slow, and ticks enter a state of diapause or simply remain dormant in the leaf litter, soil, or rodent nests.
Humidity also limits activity. Relative humidity under 70 % accelerates desiccation, prompting ticks to retreat to protected microhabitats. In dry periods, especially during summer heat, ticks reduce movement and may remain hidden for days until moisture levels rise.
Seasonal patterns differ among life stages. Larvae and nymphs, which are smaller and more vulnerable to dehydration, become inactive earlier in autumn and resume activity later in spring than adult ticks. Adults of many species, such as Ixodes scapularis, often overwinter as unfed individuals in sheltered leaf litter, becoming active again when temperatures consistently exceed 7 °C (45 °F) and humidity improves.
Photoperiod influences diapause initiation. Shortening day lengths in late summer trigger a developmental pause, causing ticks to cease questing until daylight length increases. This photoperiodic response is especially evident in temperate zones, where ticks synchronize their life cycle with host availability.
In summary, ticks are inactive when:
- Ambient temperature drops below 5–7 °C (41–45 °F).
- Relative humidity falls beneath 70 %.
- Day length shortens enough to induce diapause.
- Seasonal changes move them into overwintering sites.
During these periods, ticks remain concealed in leaf litter, soil, or animal burrows, conserving energy until favorable conditions return.