The male's huge antler-like jaws are used to wrestle rivals off a branch, and grip far more weakly than the female's short ones
Stag beetle — the mandibles are display and combat weapons, too poorly levered to bite hard.
Nature · Insects & other invertebrates
Stag beetle
Adults on the wing May–August · males to about 75 mm
Lucanus cervus — Lucanidae (stag beetles)
Britain's largest land beetle, and one of its most spectacular insects: a glossy black beetle with chestnut wing cases and, in the male, a pair of enormous antler-like jaws. Those jaws are for wrestling rival males off a branch, not for biting, and a male's grip is weaker than a female's. The adult's showy few weeks in midsummer are the end of a long underground larval life of several years spent eating dead wood, which is why rotting stumps matter so much to it.
How to spot them
- ▸Male with huge reddish antler-like mandibles, up to a third of his body length
- ▸Female smaller, all-black head with short jaws, and glossy chestnut-brown wing cases
- ▸Very large: males can reach about 75 mm including the jaws
- ▸Heavy, noisy, clumsy flight at dusk on warm still evenings in June, the body hanging almost vertically
- ▸Associated with dead and decaying wood, especially buried oak stumps, in gardens and parkland
How to know it
Britain's largest land beetle, its larvae spending several years underground eating rotting wood before a few weeks as an adult
Stag beetle — larvae in buried dead wood, especially oak stumps.
Flies heavily at dusk on warm June evenings with the body hanging almost vertical, and is often found dead on pavements
Stag beetle — the males fly in search of females, which mostly stay near the natal stump.
Its Latin name pairs a Roman family name with the word for a deer
Stag beetle — Lucanus cervus.
Its strongholds are the Thames Valley, south London, the Severn valley and the New Forest, and it is extinct across much of northern Britain
Stag beetle — a south-eastern English insect, monitored by the Great Stag Hunt.
It has an all-black, smaller lookalike whose male has no antlers at all
Stag beetle contrasted with the lesser stag beetle, Dorcus parallelipipedus.
Quick-fire facts
- •Lucanus cervus — cervus is Latin for a stag or deer
- •Britain's largest terrestrial beetle: males reach about 75 mm including the mandibles, females about 30–50 mm
- •The larva lives several years — commonly three to six — in decaying underground wood, especially oak stumps and buried roots
- •The adult does not feed on solid food; it takes sap and juices, and lives only a few weeks
- •It is protected in Britain under Schedule 5 of the Wildlife and Countryside Act 1981 in respect of sale, and is a UK priority species
- •It is a European Habitats Directive Annex II species and is declining across Europe
- •The People's Trust for Endangered Species runs the Great Stag Hunt, the long-running British recording survey
- •The lesser stag beetle, Dorcus parallelipipedus, is smaller, matt black all over, and lacks the male's antlers — the usual confusion
- •The female's shorter jaws are the ones that can actually nip; the male's are almost useless for biting
Drill it — 8 cards
1 / 8new card
Sources
- People's Trust for Endangered Species — Stag beetle facts
- Woodland Trust — Stag beetle
- Natural History Museum — Stag beetles