How does a bedbug grow? - briefly
Bedbugs develop through incomplete metamorphosis, progressing from egg to five nymphal stages before reaching adulthood, each molt requiring a blood meal. The entire cycle can complete in four to six weeks under optimal temperature and host availability.
How does a bedbug grow? - in detail
Bedbugs (Cimex lectularius) undergo a complete metamorphosis that consists of four distinct phases: egg, five nymphal instars, adult, and senescence. Each phase is dependent on temperature, humidity, and blood meals.
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Egg – Females deposit 1–5 eggs per day in protected crevices. Eggs are oval, 0.5 mm long, and hatch after 6–10 days at 24 °C; lower temperatures extend incubation. The chorion is permeable, allowing gas exchange but protecting the embryo from desiccation.
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Nymphal instars – Six growth stages follow hatching: first‑instar, second‑instar, third‑instar, fourth‑instar, and fifth‑instar. Progression requires a blood meal at each stage; without feeding, molting is arrested. Molting intervals range from 4 days (warm conditions) to 14 days (cool conditions). Each molt adds approximately 0.2 mm to body length and introduces additional wing‑pad development, though true wings never form.
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Adult – After the fifth molt, the insect reaches sexual maturity. Adults measure 4.5–5.5 mm, possess fully developed reproductive organs, and can survive without feeding for several months. Females begin oviposition within 5–7 days of their first blood meal, producing 200–500 eggs over a lifetime. Mating occurs shortly after emergence; males transfer a spermatophore that fertilizes subsequent eggs.
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Senescence – Adult longevity averages 4–6 months under optimal conditions but can exceed a year in cooler environments. Mortality rises sharply after prolonged starvation or exposure to extreme humidity.
Temperature accelerates development: at 30 °C, the complete cycle from egg to reproducing adult may finish in 30 days; at 20 °C, the same process can require 60 days. Humidity below 40 % reduces egg viability and slows nymphal growth, while 70–80 % humidity maximizes survival rates.
In summary, bedbug growth proceeds through a series of blood‑dependent molts, each governed by environmental parameters that dictate the speed and success of the life cycle.