| Main | Stag beetle larvae | Helpline | Grubs in my compost | Larva quiz |

Gardener's Larva Guide

This guide is aimed at gardeners in the United Kingdom, and it doesn't cover weevil larvae which have no legs.

Larvae photos are on millimetric paper, 1 mm smallest division. With some browsers when you move your cursor over the photos, you will be able to get more information about the pictures. In particular the larval head capsule width (HCW).
 
 

  Stag beetle
Lucanus cervus
Lesser stag beetle
Dorcus parallelipipedus
Rose chafer
Cetonia aurata
“Cockchafer” or Summer chafer
Amphimallon solstitialis [1]
Larva Stag beetle larva. HCW=9mm. Photo by Maria Fremlin, 14 June 2003. Lesser stag beetle larva. HCW=4.5mm. Photo by Maria fremlin, May 2005 Cetonia aurata larva. HCW=4.5mm. Photo by Maria Fremlin, 24 May 2003. Late instar cockchafer larva. HCW=5 mm. Photo by Maria Fremlin, 20 April 2004.
Description C-shaped. Very pale cream coloured soft transparent body, very plump almost cylindrical with segments not raised in three folds, nice to the touch. It has six stout orange legs, and an orange coloured head with very sharp brown slightly curved pincers.
Anal opening longitudinal, surrounded by 2 characteristic lobes. For more click here
C-shaped. Almost identical to the stag beetle larva, its head is somewhat paler and the pincers are straighter, also it doesn't reach the same size as the stag beetles. Generally, the gut contents are pale; they spend their time feeding only in the wood, and unlike stag beetles have little contact with the soil.
Anal opening longitudinal, surrounded by subtly different lobes. For more click here.  
C-shaped, very tightly curved sometimes, a bit like a concertina. It has a very small head and a very large bum, very short legs too; its body is very wrinkly and very firm to the touch, covered with very fine pink hair.
Anal opening transverse.
It is the easiest larva to identify correctly.
Click on the picture for a better view of the larva.  
C-shaped. Creamy coloured hairy body darker and thinner than the stag beetle, with folded segments, longer legs and not such a distinct chestnut coloured head, with curved pincers.
Anal opening transverse.  
Zooming in on the Spiracles

All the larvae are on their backs with their heads to the right.

Lucanus cervus spiracles. Photo by Maria Fremlin C shaped, all facing the same way.   Dorcus parallelipipedus spiracles. Photo by Maria Fremlin C shaped, all facing the same way.  Cetonia aurata spiracles. Photo by Maria Fremlin Kidney shaped, practically circular, rather dark.   Amphimallon solstitialis spiracles. Photo by Maria Fremlin Kidney shaped; the spiracles nearer the head face the other way.  
Size When fully grown, up to 8 cm long and nearly 2 cm thick. See here for larvae at different stages of development. When mature it is the biggest larva to be found in a garden in the U.K. Doesn't reach the same size as the stag beetle larva. Around 6.5 cm. For instance, the larva shown is fully grown, compare its size with the one on the left, also in the last instar. Around 3.5 cm when fully grown. Around 3.5 cm when fully grown, but other root-chafer species can be much bigger.
Habitat Very old pear tree stump, where stag beetle larvae were found. Scale is in 1 cm divisions. 2003, MF
Tree stumps, old trees and shrubs, rotting fence posts, decorative logs, compost heaps and leaf-mould piles. Mostly under the ground in natural situations. However it can be found feeding above the ground in log piles, etc. Note the galleries that the larvae have made. Scale is in 1 cm divisions.
Fence post with larval galleries. Photo by Maria Fremlin, February 2011.
Shares the habitat with the stag beetle but it prefers to feed above the ground. It is a kind of upstairs-downstairs arrangement.
Above is a picture of its larval galleries in a fence post which they shared with the stag beetles. The rule at the top is 15 cm long.
Rose chafer larvae found in a leaf mould heap. Photo by Maria Fremlin, 2006.
It may share the habitat with the stag beetle, but it is very frequently found in compost, leaf-mould and manure heaps in great numbers. They are the equivalent of earth worms and help break things down so they are very beneficial.
Gardeners quite often believe that they are stag beetle's larvae, which is no problem as both are very beneficial decomposers.
Click on the picture for another clutch. 
Cockchafer larva feeding on fresh roots. Seeking permission from Bayer at the moment.
Feeds on fresh roots, does great damage; usually associated with lawns.
They are not to be found in decaying wood or the compost heap.
Behaviour Stag beetle larva found on a  mulberry tree (Morus nigra) log. HCW=10mm. Photo by Maria Fremlin, 3 August 2005.
Curls up in a C or rolls up on its back as if being tickled. Also it often defecates as a reaction to being handled. Video
Lesser stag beetle larva. Photo by Maria Fremlin, April 2008.
The same as for the stag beetle. It also defecates often, like it does in this video; lighter coloured frass because it does not feed in the soil-wood interface.
Rose chafer larva moving on its back. Photo by Maria Fremlin, 24 May 2003.
If placed on a flat surface will crawl on its back! Video
In the U.S.A. larvae with similar behaviour are called “crawly-backs”.
Cock chafer larva running away. Photo by Maria Fremlin, 20 April 2004.
If placed on a flat surface it will 'run' dragging its tail end behind. Video
Pupa Cocoon found 40 cm below the soil, near rotten ash tree roots where some larvae were also found. Photo by Heinz Rothacher, Aigle, Switzerland. Late May 2002.
Below the surface in a soil compacted cocoon, the size of an orange.
Female lesser stag beetle pupa. Photo by Maria Fremlin, 25 August 2007.
Above the ground in the wood where it has been feeding.
Cetonia aurata pupa. Photo by Maria Fremlin, 16 July 2004.
In the soil/compost in a soil compacted cocoon, the size of a blackbird's egg.
Amphimallon solstitiale pupa.Photo by Maria Fremlin, 25 June 2005. In the soil, near where it has been feeding. This is the pupa from the larva shown at the top. Notice its exuvia, top right corner.
Imago Male and female stag beetles. Photo by Maria Fremlin, June 2001.
Click on the picture to view more photos.
Male lesser stag beetle. Photo by Andrew Coupe, June 2002.
Click on the picture to view more photos.
Cetonia aurata, freshly emerged from my compost. Photo by Maria Fremlin, 24 March 2003.
Click on the picture to view more photos.
Summer chafer. Photo by Frank Koehler, Germany.
Click on the picture to view another likely culprit, the true cockchafer. [1]
Action Stag beetle larvae will not damage your trees, crops or flowers.
Just leave them where they are as they don't seem to respond well to being moved.
The same as for the stag beetle larvae.  Just leave them. First, they work on your compost; then, the adullts look absolutely delightful on your flowers, which they will not damage. Pest. However if you aren't absolutely sure of their identification, take them to your nearest wild life centre/ natural history museum. 

   
LINKS: Larven in soorten en maten, by Smit, J.T. 2005 - A very interesting article comparing larvae of stag beetles (vliegend hert) Lucanus cervus, rhinoceros beetles (neushoornkever) Oryctes nasicornis, and cockchafers (meikever) Melolontha melolontha larvae.
Rose Chafer Survey - Please enter your records even if they are null, as it would be very interesting to get an update view on the distribution of this beetle.

[1] - The larva shown at the top right was picked up in my allotment where summer chafers, or June bugs, Amphimallon solstitialis, are often seen flying during summer evenings from late June; they emerge around the summer solstice, hence their common and scientific name. Among the allotmenteers they are known as “cockchafer”; elsewhere they can also be called chafer grubs or rook worms. However there is some confusion here as regards these common names, the true cockchafer, or May bug, is supposed to be Melolontha melolontha, which it is very rare in this area. It really doesn't matter as either of these chafer grubs feed on fresh roots. But it does show how misleading common names can be. For instance, billywitch is another popular name attributed to at least three beetles.
 
The results of the National Stag Beetle Survey 2002 [PDF] showed that 70% of the stag beetle sightings come from gardens, let's make them a safe haven for stag beetles.
Acknowledgements

Last modified: Fri Oct 14 12:49:44 BST 2011

| Main | Stag beetle larvae | Helpline | Grubs in my compost | Larva quiz |