Stop Press! - thanks go to Steve Bolchover for looking at these photos for me and identifying this beetle as
Geotrupes spiniger rather than
G stecorarius, and also to George for querying the id originally. However spiniger does appear to be significantly less frequently recorded in Glamorgan with only two previous records in Mapmate, and none on the NBN Gateway.
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Another large beetle arrived in the moth trap last night,
Geotrupes stercorarius, commonly known as a Dor Beetle. There are 29 previous records of this species from Glamorgan (in Mapmate). The only other one I have seen was funnily enough on the 6th of October 2012.
They are big, solid beetles that always seem very dozy. It seems hard to imagine that they have enough energy to get airborne, yet nonetheless they do. The notched and widened legs are used for burying underneath piles of dung where they create a tunnel and a larder for egg laying.
Like many beetles they often infested with small troops of mites. I'm not sure if these are parasitic or harmless. If anyone knows do please tell me!
You turn up some nice insects in your trap Adam. How do you separate this one from other Geotrupes? (I heard they were quite a difficult genus).
ReplyDeleteI believe the mites are just hitch-hikers but I could be wrong.
That's a very good question indeed George. I was lucky enough to pick up a copy of K W Harde's Field Guide in Colour to Beetles a few years ago which is sadly out of print. A book that cost £7.99 new will now set you back upwards of £50 if you can find one! There are several Geotrupes illustated in there (though not all) and this one matched stercorarius to a 'T' including the position of the fovea on the pronotum.
DeleteI wasn't aware these are an especially tricky group, so if it's an erroneous id I'm very happy to be told it's wrong!