Andrena haemorrhoa. Photo R. Mill May 2011.

Today I saw a small solitary bee visiting flowers of Woodsorrel Oxalis acetosella in the Scottish Heath Garden. It had a very reddish brown furry thorax and rather plain black abdomen and I identified it as a regular spring and summer bee visitor to the Botanics, Andrena haemorrhoa. The record was interesting for two reasons. First, it was the first solitary bee I had spotted in the Botanics this year – more about that in my next post! Second, it was as I said visiting Woodsorrel flowers – it spent quite a while inside one of the white ‘bells’ formed by the flowers before emerging to pollinate another. Now, according to Packham’s account of Woodsorrel in the Biological Flora of the British Isles series (Journal of Ecology 66: 669-693,1978), Woodsorrel has only rare insect visitors, including flies, thrips, beetles, Honey Bee and the Buff-tailed Bumblebee. No mention of any species of Andrena. I did find a mention elsewhere on the internet of a different Andrena species, A. tibialis, visiting Woodsorrel in Belgium. But I can’t find any mention of Andrena haemorrhoa visiting it. So, is this a first record for this pollinator / plant relationship?