Impressive, heavily armed and a formidable fighter. The stag beetle depends on trees and woods for its survival. Its fat larvae feed on the decaying wood of old broadleaved trees. Loss of its woodland habitat means that the stag beetle is now a nationally scarce species.
Common name: stag beetle
Scientific name: Lucanus cervus
Family: Lucanidae
Habitat: woodland, especially oak woods, as well as parks and gardens
Diet: decaying wood as larvae, tree sap as adults
Predators: birds, bats and carnivorous mammals
Origin: native
Adults: adult male stag beetles have characteristic antler-like mandibles and can grow up to a whopping 75mm in length. Females have much smaller mandibles and grow between 30-50mm. Both male and females have shiny black heads and thoraxes and brown chestnut-coloured wing cases.
Larvae: are large white grubs with orange heads and legs. They can grow up to 110mm long and live underground.
Not to be confused with: a lesser stag beetle. The female stag beetle and this species look familiar, however the lesser has a squarer shape and is matt black all over.
Credit: Arterra Picture Library / Alamy Stock Photo
Adults: survive solely on tree sap and energy stores from their larval stage.
Larvae: spend their development munching on deadwood underground, building up enough energy to emerge and mate when they reach adulthood.
The cocoon of a stag beetle can be as large as an orange.
Male stag beetles use their huge mandibles to fight off rival males and impress potential mates. After mating, the female will leave to find some deadwood where she will dig her way underground and lay up to 21 eggs.
Eggs are laid in the summer and hatch into larvae that will remain underground feasting on decaying wood, shedding their skin five times, until they grow large enough to pupate. Depending on the weather, this process can take between three to seven years.
When a larva is ready to mature, it will cocoon before emerging in adult form in May. Adult beetles have a short life-span and will die soon after mating, usually by the end of August.
Credit: William Harvey / Alamy Stock Photo
Stag beetles are largely confined to southern England and are rarely seen further north. They prefer oak woodland, but you’ll also find them in more built up areas in parks and gardens, provided there is plenty of tree cover.
In European folklore, stag beetles were thought to summon thunder and lightning.
Listen out for the loud droning buzz of the male as it flies in search of a mate on a warm summer’s night. As well as being huge and loud, you can identify a stag beetle from its strange flight - upright with its wings out behind. You might spot a female crawling on the ground in wooded areas looking for a place to lay its eggs.
Credit: Frank Hecker / Alamy Stock Photo
Stag beetles are suffering from a loss of habitat. The UK has lost much of its native broadleaved woodland and decaying wood is often removed, leading to a decrease in the natural resources stag beetles rely on. We ensure that there is plenty of deadwood on our sites to support biodiversity. These beetles are often killed by cars as they are attracted to the heat of warm tarmac, and some are mistakenly seen as dangerous and killed. If you see a stag beetle in the road, carefully pick it up (if it’s safe to do so) and move it to a safer spot.
Stag beetles are considered a pest in the Middle East where they dig into the root systems of date palms, affecting the date crop.
Trees woods and wildlife
Dead and decaying wood is one of any woodland's most important microhabitats. Learn more about why we need more of it, as well as the rare and endangered beetles, colourful fungi and other threatened wildlife that relies on it.
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Trees woods and wildlife
Get the lowdown on woodland beetles that rely on trees and the woodland ecosystem, from decaying wood to dead animals.
