Beetle bycatch

These days one of the best bits of moth trapping for me is the beetle bycatch. The summer months often turn up several species and some of these in good numbers. No two nights are the same and you soon realise that some beetle species seem to disperse, emerge or breed either under very specific conditions or over very small time frames.

A good recent example was from the moth trapping session at Wicken Fen mentioned in the last post. A couple of hour after sunset several pairs (and it did appear to be pairs) of small carabids began turning up at the traps.

I didn't immediately recognise them and assumed they were probably an Agonum species. I hadn't looked properly at the jaws. They have massive jaws.

They are in fact a Badister species and it was soon obvious that they were one of the dilatatus/collaris/peltatus trio. But which one? I'd assumed it would be the commoner dilatatus which I've recorded at Wicken before during the winter. I dissected a male and admittedly struggled a bit to clean the aedagus up, but it was then pointed out that the beetle was Badister collaris.

This appears to be a new species for VC29 and presumably for Wicken although others may have found it and the records haven't yet made it to recording schemes. It's a species that has been steadily moving northwards and so isn't an unexpected find. Assuming all the Badisters that evening were the same species then there were 10s of individuals around the traps.

The other new beetle that turned up was the rather lovely Phyllobrotica quadrimaculata, a chrysomelid and one that apparently feeds on skullcap.