Solitary bees such as alfalfa leafcutting bee (Megachile rotundata) face different—and less well-understood—challenges from pesticide exposure than their colony-dwelling honey bee cousins. Here, an alfalfa leafcutting bee visits an alfalfa flower. Pollen grains are visible behind the bee, as the bee has “tripped” the flower, causing pollen to be released outward. This facilitates pollination for alfalfa. (Photo credit: Theresa Pitts-Singer, Ph.D.)