Why Is the Pollen in My Bee Block Purple?

Although most plants produce pollen that's yellow, pollen can also be white, orange, blue, purple, brown, red, or even black, depending on the species or even the individual plant in question. It looks like the mother bee who built the nest shown below switched from foraging from a plant with yellow pollen (while working on the first brood cell) to one with purple pollen (while building all subsequent brood cells), perhaps as the former stopped flowering or the latter came into bloom. We'd need to look at a sample of the pollen under the microscope to figure out which type of plant produced this purple pollen.

One common native plant species that's native to Eastern Canada that produces pollen of different colours on different individuals is trout-lily, Erythronium americanum. An even weirder case is purple loosestrife (Lythrum salicaria): this species (native to Europe, but now common in eastern North America) can produce two different types of pollen on the same flower: small yellow pollen grains and larger blue-green pollen grains (see here and here). The two types are related to the complicated mating system of purple loosestrife, a subject that is far beyond the scope of this blog post!

--

Dr. Jessica Forrest
Associate Professor of Biology, University of Ottawa
Head of the Forrest Lab

Have bee footage or videos you want us to explain? Send them to creatures@scopabio.com!