unidentified Altica sp.

The surest way to identify beetles in the genus Altica is to check the male genitalia. Unfortunately I only ever seem to find females! Duff illustrates the spermathecae for the various species but differences are small and given variations within species I'm not sure if it is ever possible to confidently name a female Altica purely on the spermatheca. It may sometimes be possible to name species based on the plant they're found on but the only plant I've found them on is Great Willowherb and two species (oleracea and lythri) occur on willowherbs (and palustris has apparently also been found on willowherbs although that's not its larval foodplant). In the past I've attempted to name female Altica based on a combination of some or all of spermatheca, size and plant but looking back I'm very doubtful about my earliest attempts to do so and not convinced my later attempts are robust enough to record them.

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. 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