Stag beetles

by Richard Jones

I think it's going to be a good year for stag beetles in East Dulwich [...] I found the chap, pictured left, buzzing about as I was bringing in the washing off of the line.

Close-up of stag beetle on Richard 'Bugman' Jones's handI think it’s going to be a good year for stag beetles in East Dulwich. On May 16th there were three flying around in the evening, two males and a female. Then on the 29th I found the chap, pictured left, buzzing about as I was bringing in the washing off of the line. He’s small, but perfectly formed. At 35mm, excluding the antler jaws, he is way down below the usual size spectrum of 45-60mm. I’ve only ever seen one smaller, just over 27mm, found dead in a friend’s garden in Sydenham several years ago, although the books claim 20mm as the smallest on record. They can reach 70mm, and with the jaws on top of that, they can be monsters.

The seemingly extreme range in size is something to do with the stag beetle’s choice of larval food — rotten wood is very poor in nutrients. That’s why it takes 3–7 years of chewing away as a maggot before it has obtained enough protein nourishment to change into an adult. The problem with spending so much time in half-buried logs or mouldering tree stumps, is that the longer the maggot waits before turning into a beetle, the more likely it is to be disturbed by someone removing the timber, or to fall victim to predator, parasite or disease. The adult beetle may appear bold and imposing, but the larva, even a big one, is pale, soft and vulnerable.

There must be something of a nutritional gamble going on inside the grub’s metabolism — wait as long as possible to get as big and beefy as possible, or get out quick and hope that early emergence success offsets small size disadvantage.

I must make sure I send my record to the London Wildlife Trust’s stag beetle survey. Mr Beetle flew off into the dusk. Good luck to him.

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Gardeners' World Web User 08/06/2011 at 21:24

Magnificent creatures! Have seen these around my garden in Kent in the last week or so. Thanks for the link to the Stag Beetle Survey. Must send off my record too!

Gardeners' World Web User 08/06/2011 at 23:43

Very interesting, I haven't had the pleasure of seeing one of these chaps but it looks very impressive in your picture! I have a dedicated wildlife area in my garden now which consists of log piles, wild flower lawn and all my fences and partitions within this area are made from either upended logs or hurdles made from entwined branches. All ready this year I have seen a massive increase in butterflies, lady birds and other bugs and beetles so hopefully in years to come I may get the pleasure of this magnificent fella also! higgy

Gardeners' World Web User 09/06/2011 at 11:11

Cervus lucana. A magnificent beast is it not?Hopefully you are right about it being a good year for them,they deserve to survive.If only people who have gardens would put aside a piece of their patch just for beetles of all species!Except of course-woodlice,they I could do without.

Gardeners' World Web User 09/06/2011 at 15:22

I agree, Stag Beetles are magnificent. I keep the odd log pile in my garden, it does not take up much room to help beetles and other wildlife.

Gardeners' World Web User 10/06/2011 at 08:02

It is a good year for beetles. I have picked up several on the pavement on the way to my shops and put them back on the verge so they do not get trodden on. I can't ever recall doing this in the fifty odd years I have been treading this route. When I was pushing a pushchair it was the eagle-eyed occupants who would point out the worms, ladybirds etc we encountered. Children are fascinated by bugs of all kinds. I put a capsid bug and a lily beetle in a matchbox to show them how beautiful and different they can be but was never lucky enough to find a monster stag beetle.

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