Why Croydon should be inordinately fond of its stag beetles

By - Tuesday 10th June, 2014

Andy Ellis encourages Croydonians to overcome understandable feelings of alarm and to take care of our local stag beetle population

Male stag beetle, Croydon, 2013. Image by Andy Ellis used with permission

Around the middle of May I spotted a familiar shape bumbling its way across my lawn. Closer inspection revealed a female, probably in the first days or even hours of her life. This year’s stag beetles have emerged!

Stag beetles are Britain’s largest insect, growing up to 7cm or 4″ long.

Although scary in appearance, they are actually timid creatures though they will sometimes bite or nip if they feel threatened. Personally I wish they were a little more aggressive as this might deter domestic cats from trying to play with them.

The mating season is pretty much all of a male stag beetle’s life

Only the males have mandibles (pincers) or ‘antlers’. These are principally designed for battling other males during the mating season, which is pretty much all of a beetle’s life.

The larvae benefit the ecology by eating rotten wood. In fact they spend the first three or four years of their life underground before emerging as adults in May or June. The adults do not feed much and are vegetarian. Most die within weeks or months though a few do manage to survive to a second year.

Stag beetles are an endangered species but they seem to do better in London than in other parts of the country. Addiscombe, I’m glad to say, seems to have a fair number of them. Main threats to the adults are cats, lawnmowers and humans who might accidentally or deliberately crush them underfoot. This latter behaviour I find rather sad – there’s no call to be scared of them. Cats and dogs are more likely to inflict harm to humans, but nobody stamps on them! Stag beetle larvae are also at risk from badgers and disturbed habitat.

They look like horned emissaries of the devil himself

Females can fly but rarely do so. Males do fly and are a spectacular site – mandibles aloft, they look like little horned emissaries from the devil himself!

If you see beetles frequently then chances are you have a nest somewhere. This might be in an old woodpile or a dead tree stump. Help your beetles by taking care where you step, chasing off neighbourhood cats and doing a scan of your lawn before mowing it. Remember they are not a pest and will do no harm to anything in your garden.

You can also help by leaving out a little soft fruit such as a grape or plum cut in half, or a shallow tray (a jamjar lid is good) of sugared water.

If you find a beetle which is in harm’s way then you can pick it up by gently taking the section behind the head between thumb and finger. Make sure none of its feet are trapped in grass or other vegetation as this can cause injury. Put it down somewhere sheltered – ideally near the nest if you’ve identified where it is. Don’t worry, I’ve handled several and never been bitten but if you do get nipped then the bite isn’t poisonous and probably won’t even pierce the skin. Should you find the beetle a bit too scary to touch then just coax it on to a bit of cardboard and move it that way.

Male beetles in flight are following the scent of a female and are probably from another nest nearby. It’s not uncommon to see several hovering at the same time. If you go out for a close look then make sure they don’t bump into you. If they do they’ll stop flying and settle on you! Don’t panic –  lift the beetle off gently, making sure its feet aren’t stuck in the fabric of your clothes and put it gently down.

I’m fortunate in having my own colony in a dead cherry tree stump. I am, however, interested in hearing of other Croydon sightings and these can be reported via this survey form. Also, if you think you might have to disturb a habitat then please let me know via the same link and arrangements can be made to try to rescue beetles and larvae.

Andy Ellis

Andy Ellis

Descendant of an old Devonshire family, Andy has spent over 25 years of his life in Croydon. He runs a small computer business, is a student at Seishin Ryu Aikido, helps to teach the Body Harmony community fitness classes held in several libraries across the town and, last but not least, dances with the Purley-based North Wood Morris Men.

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  • Anne Giles

    Hopefully, if any appear in our back garden the dog will eat them.

  • Kathy Atkins

    You can’t tell folks not to be scared of what they’re scared of or indeed repulsed by. Most fears are irrational. Some folks – heaven help them – are afraid of cats and birds. I might have more interest if I understood the point of a stag beetle’s existence. What does it do to benefit the ecosystem?

    • PolarDog

      I know I can’t expect folks not to be scared, but at least I can point out the facts.

      In terms of benefits they bring, they are recyclers. They eat rotting wood and old tree stumps thus making way for new growth.

  • Allan Wilson

    Hi Andy. Somebody wants to build a house next to us on what used to be a beautiful orchard before it became overgrown and covered with brambles etc. Nobody here wants the build to take place of course, but planning permission has been granted unfortunately. Over the years we’ve seen several stag beetles and slow worms and a few days ago I photographed and videoed a large stag beetle in the plot. I understand these amazing creatures are protected, but what is the situation here, where their habitat will be destroyed once building starts on this new house? Does a survey need to take place before work begins etc.? Who is best to contact in Croydon Council to find out? Any help will be gratefully received. Many thanks. Allan