Janet is sending the photos soon, but I thought I’d publish and add them later as it is so long since we posted.
Next time you see bees on flowers, look closely to try and spot the pollen basket contents on each of the bees’ hind legs: usually you’ll see a yellow blob, a mixture of dry pollen and nectar and/or honey.
Pollen is an important protein source for bee larvae (grubs): 120–145 mg is needed to rear a single worker from larva to adult and there can be up to 50 000 workers in a hive in summer. Pollen composition varies between different plants: 16–30% protein, 1–10% fat, 1–7% starch though little sugar, and many vitamins. It seems that pollen from many different plants may be needed to rear healthy bees.
Although an international study found associations between heavy colony losses and regions where bees have access to intensively grown flowering crops such as oilseed rape, it’s yet not known whether these losses are the result of pesticide use, or lack of different pollen types and thus poor colony nutrition.
We know little about pollen diversity in Britain and Ireland, so last year (2014) citizen scientists joined those from Europe and elsewhere to gather more information. Now, in 2015, thanks to the gift of three pollen traps from the C.B. Dennis British Beekeepers’ Research Trust, Hughenden beekeepers are taking part in this study.
When the trap is set, bees must pass through a vertical mesh screen to get into the hive – you can see the end of it on the right hand side – and the pollen is knocked off their legs into the basket below. After 24 hours we open the trap, collect the sample and count the number of different colours.
Probably every colour comes from a different plant (for example, black pollen is likely to have come from poppies), though this will have to be confirmed by examining the grains under a microscope. You can see that each colony has worked different plant combinations.
We’ve sent our data to the University of Graz in Austria where, together with everyone else’s results, it’ll be subjected to statistical analysis. With such a large amount of evidence we are confident that the information gained will help us improve survival chances both for bees and other pollinators. Disraeli’s assertion that ‘There are three kinds of lies: lies, damned lies and statistics’ definitely won’t apply to these results!