unidentified Altica sp.

I am finding this an incredibly difficult genus. For a start the vast majority of Altica I find are females. Duff illustrates the spermathecae for the various species but differences are small and given variations within species I don't think it's always possible to name a female Altica purely on the spermatheca. Duff says most can only be identified with reference to the genitalia and only keys the males. But having now found a very small number of males, even those are proving really difficult for me.

Although I have at times identified some Altica to species, with a varying degree of certaintly, I am not currently 100% certain about many of them. I caught a lot of Altica from one site in 2025 including both males and females (though the vast majority females) and reviewing all of these together I now feel able to identify those as Altica palustris. The remaining Altica I've found over the years I am not currently happy to name with confidence and these are presented below. Hopefully with more experience I may be able to put a name to more of these.

This was potted off Great Willowherb. I suspect lythri but am not confident to record it as such.

female Altica sp. showing spermatheca, Bintree Mill (Norfolk, UK), 17th May 2022

This one came to light so no idea what its larval foodplant would have been.

female Altica sp. showing spermatheca, Wendling Beck Environment Project (Norfolk, UK), 13th May 2024

This one was potted from Great Willowherb growing beside a dyke. I think it's probably Altica lythri but suspect it's not safe to record it as such.

female Altica sp. showing spermatheca (2 views), North Elmham railway (Norfolk, UK), 20th September 2021

This one was also potted from Great Willowherb in the same area. At the time I felt it was a candidate for being Altica palustris but looking back I'm not clear why I came to that conclusion - I'd imagine lythri or perhaps oleracea are more likely.

female Altica sp. showing spermatheca, North Elmham railway (Norfolk, UK), 17th September 2021

This one came to light so no idea what it's larval foodplant would have been.

female Altica sp. showing spermatheca, North Elmham (Norfolk, UK), 18th July 2022

This was found (I didn't record what on) when I didn't have much experience dissecting beetles. I couldn't find an aedeagus so assumed it was a female but I can't find anything in my notes or photos to suggest that I found a spermatheca either (although I think it looks gravid so probably was indeed a female). I suspected it was oleracea at the time but I don't see any justification for that now (it may have been influenced by the comment in Hackston that this is the commonest species, but I'm not sure it is the commonest species, at least in Norfolk (far more records of lythri and also more palustris).

female (?) Altica sp., Thursford Wood (Norfolk, UK), 22nd May 2017

This females came to light in my garden.

female Altica sp. showing spermatheca, North Elmham (Norfolk, UK), 3rd August 2025

This male was found by suction at a different site at the edge of wet woodland. Unfortunately I managed to break the abdomen too close to the apex when trying to remove it from the beetle, resulting in the aedeagus breaking in half. Fortunately I was able to retrieve both halves, so this is hopefully not too critical. With some difficulty I tentatively identified this one is carinthiaca, unexpected as that's one of the scarcer species, however I am by no means certain of this. Altica carinthiaca is associated with Meadow Vetchling - I don't recall if there's any of that growing here but I think it's very possible - it's similar habitat to where I've seen it grow elsewhere. I shall try and remember to check next year.

Although I am not confident that this is carinthiaca, I am satisfied that it is a different species to the ones I have identified as palustris.

male Altica carinthiaca showing pronotum and aedeagus median lobe (tip in side view, flat both sides and four close-ups of the tip), Wendling Beck Environment Project (Norfolk, UK), 26th September 2025