Stag beetles

 

Stag beetles

Stag beetle with five and a half legs, brought into the conservatory by the cats a few years ago.

The stag beetle (Lucanus cervus) is Britain’s largest native beetle.

The stag beetle is so called because the male’s large jaws resemble a stag’s antlers. The female’s jaws are smaller and the female is markedly smaller than the male. However, the female’s mandibles are much more powerful than the males, though I cannot discover why that should be. The male uses his jaws in courtship displays and in wrestling other males. Males fly at dusk between May and August looking for a mate.

Stag beetle exploring toy railway track

Stag beetles are fairly widespread in Southern England but are extremely rare or even extinct in other parts of Britain. They are an endangered species across Europe. ‘Tidy’ gardens are not helpful for these creatures as there is nothing to sustain them. They are attracted to the warmth of roads and pavements, which makes them vulnerable to crushing by wheels or feet. Some people are scared by their appearance and kill them, believing them to be dangerous. Foxes, corvids and kestrels all prey on them.

They prefer areas which have the highest average air temperatures and lowest rainfall during the year. Once she has mated, the female stag beetle returns to the place she emerged from and burrows into the soil to lay her eggs, the resulting larvae being found as much as half a metre underground.

Stag beetles spend the majority of their lives underground as larvae, feeding on decaying wood. The underground stage may be anything from three to seven years. After pupating and metamorphosis, newly-emerged adults spend their first winter underground, eventually tunnelling their way to the surface in mid-May. By the end of the summer, most of them will have died. None of them will survive the winter.

The most propitious time to see males is on a sunny day, when they gather strength from the sun to enable them to fly in the evening, searching for a mate.

Yesterday we thought we had spotted our first stag beetle of the year, a female. We hadn’t seen a female before. As in past years, we reported our find to the Great Stag Hunt, organised by the PTES (People’s Trust for Endangered Species)

Lesser stag beetle

Then, in true ‘fire, aim, observe’ mode, while studying the photographs I realised that our stag beetle was actually a lesser stag beetle (Dorcus parallelipipedus) and is far from being endangered, common, in fact, and found throughout England and Wales. I had never seen one before, so it was a discovery for me. I identified it as a female because there are two small bumps on the forehead between the eyes. She reared up when Barry was photographing her, poor thing. 

We have just seen her again, making her way into the undergrowth, perhaps looking for a place to lay her eggs.

Hopefully, we will see a stag beetle or two in the garden. They are fascinating beasts, completely harmless. The larvae feed only on rotten wood and neither they nor the adults cause any harm in the garden. Adults cannot eat solid food and rely on the fat reserves built up in the larval stage, but they can drink from sap and fallen soft fruit.

Stag beetles are a priority species in the UK and are legally protected from sale.