Finding Lucanus cervus

[saye]

Hello beetle-side of the forum, I would like to ask for general tips in finding Europe's largest beetle, Lucanus cervus. Not the adults though.

What I am looking for in particular, is learning how to identify places where larvae can be found feeding. Specifically, I want to know if this can be done in a forest that is mostly constituted of Quercus robur (but also in some spots Q. suber), Ilex aquifolium and Olea europea, along with some mantles of Hedera helix. I haven't located fallen oaks, nor those that have been cut under whatever forest management requirements; some trees have in fact been cut though, but I have some understanding of the ecology of this species, and thus that oaks cut in autumn are useless for larvae since they do not undergo decomposition by the certain species of fungi needed. The presence of the species in this area is inferred by the yearly couple of collected dead, male specimens.

I also understand that pretty much burying oak logs up to a meter will attract females for oviposition eventually (next summer, of course), but that's not what I'm after.

If, in providing tips, you need more information, including photos of the forest spots, please say so.

Thanks.

[johnnyboy]

I live in south east London, we get many Lucanus cervus breeding in woodland and gardens, including my own back garden. The larvae are found in quite a wide variety of deciduous trees, in my garden I have found them in an old rotting pear tree stump. I have also found remains of female stage beetle in a well rotted Ailanthus, ( Tree of Heaven) stump area in my front garden, so most probably been laying eggs there.

If you dig around rotting tree stumps, oak, beech, Prunus etc, the larvae feed around the edges of the root zone. Signs that they are around will include bodies, wing cases of females who have died after laying their eggs.


Johnny

[saye]

Thanks Johnny.

The problem with the species is this variability you mentioned. While rotting oaks look like ideal places in woodland, gardens should be favoured in a search because that's where the larvae are more likely to be found. At least in the face of the high number of trees in, say, oak forest, which is not at all full of females ovipositing in the roots of every dying oak or tree stump. A garden tree is a much better candidate indeed. I didn't know Prunus was eligible though, much less Ailanthus if confirmed.

I attempted to dig around a rotting, already branchless oak (in the forest space mentioned), to no success. I would ask you to specify how exactly do you dig and if there is a regular depth. But I think I need to read more on the species.

Thanks.

[johnnyboy]

The stag beetle larvae seem to occur quite deep, I dug up an old rotted pear tree stump and found about thirty larvae (by accident as I wan't actually looking for them, just wanted to remove the stump) all at different stages of development. They were quite far down in the ground, over a foot or 30 cms up to about 80cms deep so it could be difficult to find them if there are lots of roots to dig through.

If there are rotting roots around otherwise seemingly healthy trees, you can smell the soil has a mushroom odour, often from honey fungus (Armilleria) which has infected the wood, another indication that the conditions might be good for stag beetles to develop.

Johnny

[saye]

Thank you Johnny, I'll post something if I find some in the next few weeks.