This blue orchard bee (Osmia lignaria) was part of a new study to find a way to mark bees and track their movements. The “mark” is egg-white powder, shown here thickly covering the hairs on its thorax. This bee was photographed in a greenhouse foraging on a cover crop of blue tansy (Phacelia tanacetifolia). (Photo credit: Emily Slingerland, USDA)