Bug with large front femurs

[Bruce Williams]

Northants garden. Photographed climbing up pot.

Help with identification appreciated.



Bruce

[Acutipuerilis]

Hiya Bruce,
This is Scolopostethus sp., and I'm having a hard time deciding whether it's affinis or thomsoni. Both are pretty common, a little bit variable, and this is boderline on practically every characher I can see...

[Bruce Williams]

Thanks for your help Joe .

Well I've checked out several pics of both your suggested species of Scolopostethus on the web and from my inexpert point of view both species look the same (and they both look like my bug too).

Unfortunately I don't have other views of this insect that might help to narrow it down.

Bruce

[Acutipuerilis]

There's a certain site about... um... British bugs... that I'm not allowed to recommend you look at because it's been used too much, but on there we mention the ways you can allegedly tell them apart. There are end-members of variation that are pretty diagnostically one or the other - the problem is that this one is ambiguous. You'd need to dissect a male to be sure here, I think.

[tristanba]

I think this is better for affinis going by the pale antennal segments 1 & 2 and dark segments 3 & 4. The wing membrane looks short and wide too.

[JRsbugs]

I had one of these too Bruce, mine was inside but I probably get them on my clothes! I decided mine was Scolopostethus thomsoni as the base of the second antennal segment is black.

Janet

[Bruce Williams]

Joe - As you suggested, I checked out the keys on the British Bugs website and came to the same conclusion as Tristan, S. affinis based on the colouring of the antennae segments.

Tristan - Thanks for help with identification. I'd come to the same conclusion based on the info. on your website (a really useful resource). However as a bug expert your opinion on id is a reassuring validation that I was on the right track .

Janet - Are you gonna post a pic of yours so we can compare antennae?

Bruce

[JRsbugs]

I used the British Bugs site too, thanks to Tristan!

Here's my 4 pics Bruce, two on the tiles, the side and under bottom view while it was crawling on a plastic dish edge but I got fed up with it walking and released the little bug.. I thought the wing membranes were longer than others I saw but the antennae fit!

[Acutipuerilis]

I wasn't convinced by affinis because the base of the third segment isn't pale, as it usually is (but not always); in thomsoni the apex of the second is usually dark, but not always. The membrane length is typical for thomsoni but definitely on the truncated side for affinis - although still within the range of possibility. So, still not convinced either way, I'm afraid. If the base of the first antennal segment being dark or pale is diagnostic, that would be brilliant... but I've not read anywhere that says either way, so I suspect it isn't.

[JRsbugs]

I should have said the 'apex' of the second antennal segment is black on mine!