As beekeepers we are used to seeing pollen pellets of a solid color. This is due to the famous “floral fidelity” of honey bees. It means that on any one foraging trip, a honey bee collects pollen from only one species of plant. Floral fidelity is one of the reasons honey bees are such good pollinators: pollen from one plant species is not wasted on another.
Most pollinators are less particular. And even though many of those pollinators are quicker than honey bees when moving from flower to flower, they may jump species in the middle of a foraging trip and thereby lose some of their efficiency.
The pictures below came from my garden yesterday. If you look carefully at the pollen pellet of this bumble bee, you can see that she has collected pollen from at least two species on this trip. The orange pollen (unknown source) is underneath the Ceanothus pollen, which is a cream color. I’ve seen pictures of this phenomenon in books, but this is the first time I’ve seen it in the field.
I was about to delete these out-of-focus bumble bee pics when I just happened to notice the pollen.