Where the bee sucks

Unsurprisingly, the solitary bees I have been working with recently have often been covered in pollen (they have a lot to cram into their short adult lives). I took this female Osmia bicornis from the Geranium macrorrhizum which attempts to overrun my garden (I've never rated it much as a wildlife plant but it has filled a gap which the bees have been very grateful for over the last few weeks). 

 

The large orange pollen grains are obvious, but also very distinctive under the microscope:

My favourite so far is Daisy pollen, Bellis perennis: 

So far so easy - I know the flowers I have taken the pollen from. But can I identify pollen taken from bees to work out what they have been feeding on? There are several useful websites for identifying pollen. The Global Pollen Project is good, but my favourite is the Northumbrian Bees pollen gallery. 

By coincidence, this month's Microscope Club also involved messing around with pollen and as usual, I picked up some useful tips. Size as well as shape is a key feature of identifying pollen grains and the standard is to make sure the pollen is fully hydrated before measuring, thus aqueous media are used. Glycerol Jelly is the standard medium but is a pain to work with, so I'm using Magnacol aqueous mountant. In water alone pollen grains are quite frisky and move around, making photography difficult. The Magnacol mountant contains PVA and is quite viscous, which fixes the grains better. 

This is very much a work in progress but it will be interesting to see what I can find as the season progresses (assuming there are enough hours in the day). 

Where the bee sucks, there suck I:
In a cowslip’s bell I lie;
There I couch when owls do cry.
On the bat’s back I do fly
After summer merrily.
Merrily, merrily shall I live now
Under the blossom that hangs on the bough.