Long-horned bee Eucera longicornis pollinating an Ophrys scolopax orchid. The orchid flower imitates in shape, colour and smell, the female long-horned bee. Male bees are sexually attracted to the flower and attempt to mate with it. In the process of male bee movements, the head of Eucera brushes against the pollen bearing pollinaria" of the flower and these are released onto the bee's head. The bee carries this yellow pollen structure to another orchid plant and acts as pollinator. The orchid-bee attraction occurs at a time when female Eucera bees are not yet born, and the male has no choice but to visit this Ophrys orchid."