When do ticks go into hibernation? - briefly
Ticks enter a dormant state during the colder months, typically from late autumn through winter, with timing varying by species and regional climate. They resume activity when temperatures rise and humidity becomes sufficient for host seeking.
When do ticks go into hibernation? - in detail
Ticks enter a dormant state during the coldest months of the year. The transition is triggered primarily by sustained low temperatures and reduced daylight. Most species cease activity when ambient temperature falls below 5 °C (41 °F) for several consecutive days; some cold‑adapted ticks remain active until temperatures drop to 0 °C (32 °F). Day length shorter than 12 hours also reinforces the onset of dormancy, but temperature is the decisive factor.
The timing varies among species and regions:
- Ixodes ricinus (European castor bean tick) – dormancy typically begins in late October to early November in temperate zones, coinciding with average nightly temperatures under 7 °C.
- Dermacentor variabilis (American dog tick) – enters diapause in November in the northern United States, when nightly lows consistently stay below 4 °C.
- Amblyomma americanum (Lone Star tick) – ceases questing activity in December in the southeastern United States, as average daily temperatures drop beneath 10 °C.
- Ixodes scapularis (Black‑legged tick) – becomes inactive from November through March in the northeastern United States, with a threshold of approximately 5 °C.
Physiological changes accompany the shift to dormancy. Metabolic rate drops to less than 10 % of active levels, and the tick’s cuticle becomes more resistant to desiccation. Energy reserves, stored as glycogen and lipids, sustain the insect through the period without blood meals. Some species, such as Ixodes ricinus, overwinter as unfed adults; others, like Dermacentor variabilis, may overwinter as engorged females that have completed the blood‑feeding stage before the cold set in.
Microclimate conditions can modify the exact onset date. Ticks sheltered in leaf litter, rodent burrows, or under snow cover experience delayed cooling and may remain active a few weeks longer than those exposed on the surface. Conversely, early frosts in open habitats can force an earlier entry into dormancy.
When temperatures rise again in spring, ticks resume host‑seeking behavior. The reactivation threshold is generally around 7–10 °C, with activity increasing sharply once daytime temperatures exceed 12 °C and humidity remains above 80 %. This seasonal pattern repeats annually, aligning tick life cycles with the availability of suitable hosts.