When do bedbugs emerge from dormancy? - briefly
Bedbugs resume activity when ambient temperatures consistently rise above roughly 21 °C (70 °F) and they detect a viable host, typically in early spring or after a heated environment is established. They stay dormant during colder periods and become active as soon as conditions become favorable.
When do bedbugs emerge from dormancy? - in detail
Bed bugs (Cimex species) enter a dormant state when environmental conditions become unsuitable for active development and feeding. The transition out of this state is governed primarily by temperature, photoperiod, and the presence of a viable blood source.
Temperatures above approximately 15 °C (59 °F) stimulate metabolic activity. When ambient warmth consistently exceeds this threshold for several days, nymphs and adults resume movement, seek hosts, and begin feeding. Laboratory experiments show that a rise from 12 °C to 20 °C accelerates emergence within 48 hours, whereas temperatures below 10 °C prolong dormancy for weeks or months.
Day length influences hormonal regulation. Increasing daylight hours in spring signal the approach of favorable conditions. Studies indicate that a photoperiod of 12 hours of light or more, combined with suitable temperature, triggers the cessation of diapause in adult females, prompting oviposition.
Humidity plays a secondary role. Relative humidity above 50 % supports cuticular water balance, facilitating activity. In dry environments, bed bugs may remain quiescent despite adequate temperature until moisture levels improve.
Host availability is the final cue. Presence of a warm-blooded host—detected through carbon‑dioxide, heat, and kairomones—induces immediate emergence. In field observations, infestations become noticeable when occupants return after a period of absence, such as after holidays or heating shutdowns.
Typical seasonal pattern:
- Late winter (February–March in temperate zones): temperatures rise above the critical threshold, daylight length increases, and bugs become active.
- Early summer (May–June): peak activity as conditions remain optimal.
- Autumn (September–October): activity persists until cooling temperatures fall below the dormancy threshold, prompting re‑entry into a quiescent phase.
In controlled environments, manipulation of temperature and light can induce emergence within 24–72 hours, confirming the primacy of these factors. Consequently, monitoring ambient temperature and ensuring consistent heating during colder months can prevent premature activation, while abrupt temperature spikes can unintentionally provoke a resurgence of activity.