The lifecycle of the stag beetle Lucanus cervus © M Fremin and C Nahaboo
The duration of the life cycle, which is a complete metamorphosis, is not precise. On average full development can take between 4-6 years. Fully grown adults emerge in the spring with the males emerging first.
Adults have a large size range, the males can range from 40mm to 70mm long and are consistently larger than the females, who can be as small as 25mm, and lack the enlarged mandibles of the male. Unlike the males, the females are capable of biting with their mandibles.
Both sexes are black with the exception of the wing cases which are a reddish brown. (The female can sometimes be confused with the lesser stage beetle, Dorcus parallelipipedus, but this species has black wing cases). In the male the mandibles are also a reddish-brown.
Females lay their eggs in the vicinity of decaying wood, below ground in a prepared bed. Eggs hatch after approximately 3 weeks. The developing larvae feed on the decaying wood.