Ploughing her own furrow

When I saw this bee I said "YES!!", because I thought I'd found a female Orange-legged Furrow Bee (Halictus rubicundus) - a species I've only recorded here a couple of times previously. This was shortly followed by "Aaargh - NO!!", when I realised that I'd been fooled, yet again, by one of the Lasioglossum species. Which are also Furrow Bees, so I get a few marks for recognising that much, but they're base-banded, as opposed to Halictus, which are end banded. Honestly, I don't fully understand either, but I think it's a question of whether the hairy white fringes on the abdominal tergites are growing forwards or backwards - and that's as far as I'm prepared to go.

Anyway, the thing that most clearly says "Lasioglossum" about this little bee is the fact that her abdominal tergites have those slightly translucent hind margins, which in the field appear red, and which Halictus species don't have. Not many Lasioglossum species do either, to be fair, and the fact that she does makes this specimen most likely to be L. calceatum, the Common Furrow Bee. Lasioglossum calceatum is a smaller and slimmer bee than Halictus rubicundus - which is about the size of a Honey Bee, and has a broader head than this - and indeed, a broader everything else.

So why do I keep getting fooled by my Furrow Bees? Because I'm a fool, obviously - but also because they're pretty manic little things, and move so fast that their anatomical features tend to go past you in a blur of legs and wings. Ideally you'd want to use a shutter speed of 1/1000 second to freeze that motion blur, but the 1/640 I was using here on high-speed burst just about did the job, albeit with a lot of discarded frames. The reason I was able to take so many photos of this female was that she spent a good ten minutes working this patch of aubretia, seemingly desperate to get her head as deep as possible into the flowers to drink the nectar. Aubretia are tubular flowers though, and the Furrow Bees are short-tongued, so she was virtually drilling her head down into each bloom, pushing against the petals with all six feet to try to reach the nectary. 

I generally see Common Furrow Bees kicking up a pollen storm around the heads of dandelions, and it made me wonder what it is about the taste of aubretia that made this one so determined to access that nectar, when flowers that are so much better suited to her physique were available just a few feet away.