When do bedbugs shed their shell? - briefly
Bedbugs shed their exoskeleton after each nymphal molt, usually 4–7 days following a blood meal, with the interval shortening as temperature rises.
When do bedbugs shed their shell? - in detail
Bedbugs undergo a series of molts as they progress from egg to adult, shedding their outer cuticle at each developmental stage. The process, known as ecdysis, occurs five times for females and four times for males, because the final molt produces the adult form, which does not shed again.
Timing of each molt
- First instar to second instar: 4–6 days after hatching, provided temperature remains between 21 °C and 29 °C (70 °F–85 °F). Cooler conditions can extend this interval to 10 days or more.
- Second to third instar: 5–7 days under optimal temperatures; lower temperatures delay the event, while temperatures above 30 °C accelerate it.
- Third to fourth instar: 6–9 days, with a similar temperature dependence.
- Fourth to fifth instar (females only): 7–10 days; males skip this stage and proceed directly to adulthood after the fourth instar.
- Fifth instar to adult: 8–12 days for females; males complete the transition after the fourth instar in roughly the same period.
Factors influencing molt intervals
- Temperature: Each 10 °F (≈5.5 °C) increase shortens the developmental period by about 20 %. Conversely, temperatures below 15 °C (59 °F) can double the time between molts.
- Blood‑meal availability: A successful blood feed is required before each molt. Inadequate or delayed feeding postpones ecdysis.
- Humidity: Relative humidity below 40 % slows metabolism, extending the molt schedule; optimal humidity (70–80 %) supports the standard timeline.
- Population density: High crowding can limit access to hosts, indirectly delaying molts.
Typical overall schedule
Under stable, optimal conditions (≈25 °C, 75 % RH, regular blood meals), a bedbug progresses from egg to reproductive adult in approximately 30–40 days. Each shedding event marks the transition to the next instar, with the final molt occurring shortly after the last blood meal that triggers adult maturation.
Understanding these intervals assists in predicting infestation development and timing control measures, as interventions targeting vulnerable instars are most effective shortly before or during the ecdysis window.