Beetle ID anyone?

jezlee · #1 (**permalink**) 11-06-2007, 09:51 AM

Hello all, found this chap ambling across a woodland path in the Forest of Dean at the weekend. Quite a decent size - maybe between 10 and 15mm in length. Does anybody recognise him?

Ukwildlifeo · #2 (**permalink**) 11-06-2007, 10:15 AM

looks like a Dor beetle Geotrupes stercorarius

jezlee · #3 (**permalink**) 11-06-2007, 10:23 AM

Quote:

Originally Posted by Ukwildlifeo

looks like a Dor beetle Geotrupes stercorarius

Thanks! I've looked it up on Google, and all the pics and descriptions of beetle and habitat seem to match ...

Paul mabbott · #4 (**permalink**) 11-06-2007, 11:28 AM

Geotrupes, clearly but there is no way we can say G. stercorarius from this picture. That's a possibility but given that the size was "10 - 15 mms" then the most likely option is G. stercorosus. Indeed, it is somewhat rounded so that seems the best option, however I would label it Geotrupes sp possibly G. stercorosus. It might also be G. spiniger!

jezlee · #5 (**permalink**) 11-06-2007, 11:51 AM

Quote:

Originally Posted by Paul mabbott

Geotrupes, clearly but there is no way we can say G. stercorarius from this picture. That's a possibility but given that the size was "10 - 15 mms" then the most likely option is G. stercorosus. Indeed, it is somewhat rounded so that seems the best option, however I would label it Geotrupes sp possibly G. stercorosus. It might also be G. spiniger!

Thanks, Paul ... you're a BIG help ....

SparklySarah · #6 (**permalink**) 11-06-2007, 11:56 AM

Seem to get loads of them in the Forest of Dean! Go for walks and rides there every Saturday and they pop up everywhere....... quite often flat!

jezlee · #7 (**permalink**) 11-06-2007, 12:00 PM

Quote:

Originally Posted by SparklySarah

Seem to get loads of them in the Forest of Dean! Go for walks and rides there every Saturday and they pop up everywhere....... quite often flat!

Yes, Sarah, I saw two squashed ones before I came across this live specimen!

Paul mabbott · #8 (**permalink**) 11-06-2007, 12:00 PM

Quote:

Originally Posted by Paul mabbott

Geotrupes, clearly but there is no way we can say G. stercorarius from this picture. That's a possibility but given that the size was "10 - 15 mms" then the most likely option is G. stercorosus. Indeed, it is somewhat rounded so that seems the best option, however I would label it Geotrupes sp possibly G. stercorosus. It might also be G. spiniger!

Sorry, didn't explain why - just got another cup of coffee: hard day yesterday

There are several very similar dor beetles although some are very rare and the number of elytral striae cuts this down to three. These three are separated by the number of carinae on the hind leg tibiae (which aren't visible on this picture) and then by the number of hairs on the underside of the body (not visible for obvious reasons). The only clues that we have therefore are (a) the roundedness of the body (which is a subjective thing and not reliable) and (b) the length: G. stercorosus is 12-19mm while G. stercorarius and G. spiniger are 16-26mms so ....

jezlee · #9 (**permalink**) 11-06-2007, 02:09 PM

Quote:

Originally Posted by Paul mabbott

Sorry, didn't explain why - just got another cup of coffee: hard day yesterday

There are several very similar dor beetles although some are very rare and the number of elytral striae cuts this down to three. These three are separated by the number of carinae on the hind leg tibiae (which aren't visible on this picture) and then by the number of hairs on the underside of the body (not visible for obvious reasons). The only clues that we have therefore are (a) the roundedness of the body (which is a subjective thing and not reliable) and (b) the length: G. stercorosus is 12-19mm while G. stercorarius and G. spiniger are 16-26mms so ....

Thanks for that, Paul .... I'm going to have to start measuring these things, and not rely on my memory - but looking at a ruler in front of me now, I would have said definitely no bigger than 20mm, which, as you said earlier, probably points to G.stecorosus ....

But it also could be a small G. stercorarius or G. spiniger ...

Paul mabbott · #10 (**permalink**) 11-06-2007, 04:41 PM

Quote:

Originally Posted by jezlee

Thanks for that, Paul .... I'm going to have to start measuring these things, and not rely on my memory - but looking at a ruler in front of me now, I would have said definitely no bigger than 20mm, which, as you said earlier, probably points to G.stecorosus ....

But it also could be a small G. stercorarius or G. spiniger ...

... and if I've mis-counted the striae, G. mutator! I'd just sticky with Geotrupes sp ....

PS: Not easy getting a measure - eventually you'll learn to judge it by eye: in most cases it isn't a matter of measuring to 1mm (although, in some cases measurements may be critical to 0.1mm!). It's not easy getting a scale to put in your picture so some people go by a penny coin or a matchstick ... if you can get them in the field of view without frightening off the insect!