Three Common Pterostichus Beetles

 

I regularly find carabid beetles during winter log lifting, particularly medium-large sized species from the Pterostichus genus. These smart predatory species can be found in a range of habitats locally being most common in either hedgerows, agricultural land, scrub and woodland. P. madidus above and P. melanarius appear to be particularly common on heavy agricultural soils and open grassland habitats, with the other regularly found species P. niger appearing more fond of higher humidity found in woodland, and occasionally in wet grasslands.

 

These three species are all similar in size and colour with P. melanarius and P. niger being most similar and differeing with P. melanarius having a rounder pronotum and not sinuate (S-curved) like in P. niger. P. melanarius has a small tooth in the rear corner of the pronotum, which P. niger lacks. P. madidus has two forms the typical black legged form and the equally as common red-legged form var. concinnus.