When do bedbugs shed their skin? - briefly
Bed bugs molt after each nymphal stage, typically every 4–7 days under optimal temperatures (20‑30 °C). The process continues until the insect reaches adulthood, after which no further shedding occurs.
When do bedbugs shed their skin? - in detail
Bed bugs (Cimex lectularius) undergo a series of molts as they progress from egg to adult. Each molt, called ecdysis, involves shedding the outer exoskeleton and is essential for growth.
The insect experiences five immature stages, known as instars. Molting occurs after each instar, resulting in a total of four ecdysis events before reaching maturity. The timing of each molt depends on temperature, food availability, and humidity.
- Temperature: At 25 °C (77 °F), the first instar typically lasts 4–6 days before the first molt. Warmer conditions (30 °C) shorten the interval to about 3 days, while cooler environments (20 °C) extend it to 7–10 days.
- Blood meals: A successful feeding triggers hormonal changes that initiate ecdysis. Without a recent blood meal, the nymph may remain in its current stage for an extended period, sometimes weeks, awaiting nourishment.
- Humidity: Relative humidity above 50 % supports normal development. Low humidity can delay molting and increase mortality.
The molting process itself unfolds in three phases:
- Pre‑ecdysis: The nymph stops feeding, secretes a thin layer of fluid that separates the old cuticle from the underlying epidermis.
- Ecdysis: The insect contracts its body, forcing the old exoskeleton to split along predetermined lines. The cuticle is peeled away, exposing a soft, pale new exoskeleton.
- Post‑ecdysis: The new cuticle hardens through sclerotization and melanization, a process that may take several hours. During this period, the nymph is vulnerable to predation and desiccation.
Overall development from egg to adult, encompassing all four molts, requires approximately 5–7 weeks under optimal laboratory conditions (25–27 °C, 70 % RH) with regular blood meals. In cooler or resource‑limited settings, the complete cycle can extend to several months.
Understanding the precise timing of each ecdysis event aids in the identification of infestation stages and informs the scheduling of control measures, as nymphs are most susceptible to insecticides immediately after shedding their cuticle.