An unlikely pollen source

I observed a couple of two-spotted sunflower bees, Melissodes bimaculatus, foraging for pollen on this Floriani Red Flint corn in Boulder, CO. While it may seem strange, I observe bees foraging on corn and other grass for pollen fairly frequently. These could provide important resources if other host plants are scarce or may be used to supplement pollen provisions. These two bees returned repeatedly and filled their scopa up each time. You can easily see the yellow corn pollen packed onto their hind legs.