Red Pollen

I've had these photos on file for awhile of a honeybee with a red dot of pollen on her pollen pack of otherwise yellow pollen. She is seen here foraging on red buckwheat, Eriogonum grande rubescens. Is the red pollen from another flower or from the aptly named buckwheat?

Now that I returned from a quickie vacation to the beautiful Owens Valley I can spare a little time to investigate further. Pollen comes in lots of colors, not always what you might assume from the flower color or name. I went out back to check out the buckwheat pollen first hand. Most of the flowers are now dried up, but a few spunky stamens persist and I was able to shake out some grains onto my palm. They are red, rather large for pollen in that they felt like small sand grains as I rubbed them around. Using my handy Tasco 30x pocket scope, I could see they are shaped like little concave 3-sided oval purses, very similar to the image seen here for E. hooveri, but smoother. I checked the full range of flower colors I have, from the dark pink flowered through light pink to white, and all of the pollen collected was red or very dark pink.

So the dots of red on the pollen pack are likely to be red buckwheat pollen, unless somebody has another explanation. Why this bee gathered some buckwheat, went to another (yellow) pollen source then back to the buckwheat is beyond the scope of today's investigation.

Thanks Wiki and UC Berkeley for tables and info.