An insect visit causes the sexual column to trip, but, unlike the alfalfa sexual column, it does not return to its original position in the keel when the pressure is removed. Apparently, like ball and crimson clover, black medic will set seed in selfed flowers, but more seeds will set if crossing occurs.
Honey bees are the chief visitors to black medic flowers.
They visit a few flowers on an inflorescence then move to other inflorescences, thereby increasing possible crossing. Many other bees are of some value as pollinators.