Bembidion lampros

Both Bembidion properans and the similar Bembidion lampros are common but I have found their separation really tricky. I was perhaps slightly thrown by finding mostly properans despite knowing that lampros was supposed to be the commoner species (in retrospect I wonder if lampros is indeed the commoner species but properans is more prone to coming to light, the means by which I mostly find them). Some were clearly properans while others were less convincing, and it wasn't until I had the opportunity to study some lampros specimens in a friend's collection that I felt comfortable calling them all properans. I had previously identified lampros, but after examining a range of specimens in detail I decided that my earlier lampros identifications were not safe (though at least some of them may well have been correct).

Then in 2023 I caught a larger number of Bembidion than usual. Most were identified as properans, but then I came across another tricky one. The 7th striae were clearly weaker than the 6th, and relatively short - though still longer and more distinct on one side than I had recalled seeing on my friend's lampros specimens. There was a row of 6 relatively weak punctures on one side though just 3 very indistict and irregularly-spaced punctures on the other side. I also thought the frontal grooves looked better for lampros. I still had access to my friend's collection so examined them again. One had 7th striae more distinct than I had remembered after my first look - really not very different from the one I was now looking at. So if that was lampros (and his collection had been checked by a very experienced coleoptorist) then so was mine.

It was short-winged. I dissected it in the hope of finding a male aedeagus to compare with those of properans that I've previously examined, but this one proved to be a female. I've included a picture of its spermatheca below just in case that proves to be useful but as far as I know it isn't.

female Bembidion lampros showing frontal grooves, elytral striae on both sides and spermatheca, North Elmham (Norfolk, UK), 27th April 2023

This one was in my garden, but unlike the majority of my garden records of Bembidion which have come to light, this one was found in my vane trap. The 6th striae were short (less than half way) and there was no trace of a 7th.

Bembidion lampros showing frontal grooves and elytral striae, North Elmham (Norfolk, UK), 2nd May 2024

In view of the difficulty I've had identifying lampros vs. properans, and in view of the fact that properans seems to be the more common species here, and in the absence of close-up photos showing the relevant ID characters, I think it's best to treat my old records of lampros with caution (especially as at least one of my photos looks like it shows quite a strong stria 7). Having now established that lampros does occur here, it's entirely plausible that some (or perhaps all) of these were identified correctly - but I'm no longer confident of that.

Bembidion sp., identified at the time as Bembidion lampros, North Elmham (Norfolk, UK), 26th May 2018

Bembidion sp., identified at the time as Bembidion lampros, North Elmham (Norfolk, UK), 27th May 2018

Bembidion sp., identified at the time as Bembidion lampros, North Elmham (Norfolk, UK), 8th May 2020

This one was on an Oak tree trunk.

Bembidion sp., identified at the time as Bembidion lampros, North Elmham Cathedral Meadows (Norfolk, UK), 5th May 2018