No interactions present.
Matt is spot on. This is most likely to be A. clarkella.
What this all highlights is how utterly unhelpful some of the manufactured "English Names" of species are. A. haemorrhoa is one of the later spring species of Andrena to emerge. If the manufacturers of vernacular names were doing their bit by translating latin epithets into English then the "Early Mining-bee" should be Andrena praecox. I'll leave others to work out a good translation of "haemorrhoa"
Thank you for these comments. I still have a number of solitary bee images, not posted, from last year. I may put some more up but am inclined to wait and see what transpires this year and if I can get images from more angles.
Is there any known nuance of habitat that would explain why A. clarkella appears early?
A.clarkella, along with a few other Andrena species, specialise in collecting pollen only from sallow and willow catkins. These flower early, so the bees have to be out early to match the flowering.
Tachinid Recording Scheme
TRS Facebook Page
Why could this not be Andrena nitida? The abdomen of A.nitida appears black (almost hairless) and shiny. The abdomen of clarkella is very hairy so doesn't appear shiny. Also in the BRERC (former Avon) area A.clarkella has yet to be recorded whereas nitida is very common from late March onwards.
NBN shows a few records for A.clarkella for the Somerset/Avon region.
As you say, A.nitida has a shiny, almost hairless abdomen. It also has a couple of patches of white hairs on the upper part of the abdomen and I can't see those in the picture, this bee has an all black abdomen that is hairy. Also, the overall "jiz" for this bee is just not right for A.nitida.
A. nitida has very pale hairs on the sides of the thorax and obvious pale patches on the lateral margins of the first tergite (these are distinct even in worn & faded specimens).
I would also caution against using known distribution as a key character. With many of the commoner species, the finer details of distribution are rather imperfectly known
Lat/Lng: 51.43372, -2.76236
OS grid ref: ST471707