Because the tomato flowers have evolved to attract bees, they have spread-out petals and are white to human eyes (bees, like most insects, can see into the ultraviolet range as well as our visual range of wavelengths). The pollen is often stuck together in clumps called "pollinia", which in turn get stuck to the bee. Bees are extremely hairy, and carry tiny electric charges which attract the pollen onto their bodies. Honey bees have special pollen baskets, usually on their rear legs; they groom the pollen off their bodies into these pockets.