Hibernating beetle?

[Gerel]

Hi

Trying to do my bit to keep up the invert. forum activity level. I've been finding quite a few of these recently, apparently hibernating under loose bark, sometimes several of them clustered together. 10mm or so long, they release a fairly obnoxious smelling liquid when hassled. Some sort of ground beetle?



Sorry for the pics, it wouldn't keep still

Steve

[Jason Green]

Hi Gerel

I would say a species of Darkling beetle, tenebrionidae genus. I base this on general looks and the 11-segmented antennaes.

Try Tenebrionidae.net...

[squishy]

maybe Silpha Atrata? it has some very profound similarities (thats the Staphylinidae (so it's actaully a rove beetle ))

i'm actually fairly certain of that

[Paul mabbott]

Yes, one of the Silphidae - I'll key it out tomorrow; the site's running too slowly for me to spend more time here tonight.

[Dogghound]

The problem with these is you often need an actual specimen they are often differenciated by the height of their elytral ridges, not sure if its possible to ID it from a photo with 100% confidence. Phosphuga atrata is the most abundant out of them all.

[Jason Green]

Oh yes, I can see similarities, aesthetic suggestions of Roves. Thanks for the info, another thing hopefully learnt!!

[Gerel]

Thanks for the replies all. I just read the following on Phosphuga/Silpha Atrata (just love these name changes)

Adults and larvae feed on pulmonate snails and earthworms. The adult attacks a snail with a poisonous bite causing it to withdraw into its shell and fill the entrance with a viscous fluid, the beetle then eats its way through the fluid with the assistance of a secretion which dissolves both the fluid and the snail tissue. They are active under logs and bark of fallen or standing deciduous timber from october, often in groups of up to a dozen and usually in very damp conditions. Large numbers can be found in January and february and later, during the first warm days in march, can be seen crawling on trunks or logs in the open. After april or may, depending on season, they are seldom seen

Seems I was wrong about the hibernation theory as well. What sort of insect is only active in the Winter, honestly!

Steve

[squishy]

no, the Silpha atrata does do quite dormant in winter, its not quite hibernation, but its somewhere close. so your theory is was sort of correct

[Dogghound]

Phosphuga/Silpha Atrata doesnt go dormant squishy, similar to alot of carabids they remain quite active under logs bark etc. If you go out and have a look you will find some im certain of it.

[Paul mabbott]

Yes Silpha (Phosphuga) atrata - this family (Silphidae - unrelated to Staphylinidae) are fairly easy to key from good photographs. In this case has extendd head and round front of pronotum; fial antenal segrments are squareish or longer than wide = 'Phosphuga'. Pronotum is uniformly puncuate etc = atrata.