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Small Stag Beetle - Platycerus quercus - male

Small Stag Beetle - Platycerus quercus - Male
Parkwood, Durham County, North Carolina, USA
May 15, 2006
Size: 10 mm
Posed. There is a droplet of water on the tip of the abdomen. Length measured by photographing adjacent to a scale. I presume this is a male due to the enlarged mandibles--some other examples we have in the Guide have smaller mandibles, and references indicate there is sexual dimorphism. This is an example from North Carolina--so far we just have examples from the Northeast.

This beetle emerged from a large jar, kept outside in the shade, where I am keeping a bunch of natural rotting wood substrate including, 2-3 pupa of presumed Lucanus species. (I expect these in July.) It is likely this was from the smaller larva I photographed, thinking it was a small Lucanus, and later found in a pupation chamber :

I'm not sure I took enough detailed photos of each grub to see if there were any differences, but the small size (40 mm, and thin) of those two, along with the adult emergence, makes me pretty confident in the placement with Platycerus virescens.

Images of this individual: tag all
Small Stag Beetle - Platycerus quercus - male Small Stag Beetle - Platycerus quercus - male

Well done!
I have been waiting for these results, Patrick, very small beetle though... Could you please tag the previous photos, if any, so that we can see the different stages?

Possibly not from those larva
I do not believe this beetle to be from those huge larvae--they were 10-20X larger than this. I had added a bunch of rotting wood chips and mulch to the medium, and I am presuming this is where this small stag beetle came from. Good point, though, perhaps one of the smaller larvae was this one. (There were three large larvae to start. Maybe one was much smaller--I'll check the original photos.) Hmm, a real puzzle. I'll dig through the rearing container and see who's still down there.

Patrick Coin
Durham, North Carolina

Very puzzling indeed...
It will be well worth checking the contents of your jar with the utmost care, their pupal cases are very, very fragile. Lucanus capreolus pupates in the soil, but I'm not sure of the other guy. However some Lucanidae pupate in the wood; for instance I found a Dorcus parallelipipedus once in a dead oak branch, see her here. Did you put any branches there as well?

What went into that jar
Unfortunately, I just dumped a bunch of soil, compost, and rotting wood chips into that jar. I was trying to provide food for the big grubs--I did not think about any other biota.

I will look at it, and my old photos as well--likely in a week or more, as I'm busy right now. There were three grubs--maybe one was much smaller--I remember that vaguely. It did not occur to me there might be more than one species.

Unfortunately, this was not a rigorously controlled scientific experiment--it was just me playing around, trying to get some adult beetles. Results have been good for me so far--I had not seen the Platycerus previously.

Patrick Coin
Durham, North Carolina