‘Thunder beetles’ show strength of capital’s ecology

Stag bettle in Penge garden credit Chris Keniger

London’s stag beetles defy European declines to make a home in the city

A charismatic beetle continues to thrive in London – even while its continental cousins face a struggle to survive. Right now in the gardens of Greenwich and the parks of Peckham, stag beetles that have lain low as larvae for years are emerging from their dead wood dens to meet their mates.

Despite stag beetles being globally endangered and declining elsewhere in Britain, the capital appears to be a hotspot. Late spring and early summer is the season for stag beetles and over the past 20 years Londoners have recorded sightings via London Wildlife Trust’s stag beetle survey.

Each year Britain’s biggest beetles emerge from tree stumps and logs in gardens, parks, woods, and anywhere there’s dead wood. The males are 6-8cm in length and sport ferocious-looking (but harmless) ‘antlers’ with which they wrestle other males for female attention. The females lack such prominent ‘antlers’ and seldom fly, instead attracting males using pheromones. Stag beetles are often spotted on sultry, warm evenings, an hour or two before dusk and often before storms – hence the nickname ‘thunder beetles’.

Their decline across southern Britain is attributed largely to the tidying up of parks and the wider countryside, which has led to the removal of tree stumps and dead wood, where beetle larvae grow. However, London has enjoyed a stag beetle renaissance, with many park managers and gardeners now leaving stumps and logs in place – homes for a range of wildlife.

Stag beetles are found across Greater London, but for reasons not fully understood are most commonly seen south of the Thames. More than 1,100 were reported to London Wildlife Trust in 2017, a 10% increase on 2016. As well as records the Trust also collects images and videos to encourage people to protect the beetles – the best are shared on Twitter via @StagBeetleSam.

Mathew Frith, Director of Conservation at London Wildlife Trust, said: “While stag beetles are under pressure in much of Europe, in London they defy expectations. Many people don’t think of the city as a wildlife refuge but these charming insects are a reminder that London remains a valuable habitat for a very wide range of species, many of them benefiting from the capital’s unique environment. I hope more Londoners will contribute to our stag beetle survey this year.”

Visit wildlondon.org.uk/stag-beetle-survey to record your sighting.