Legs of insect pollinators have features adapted to gripping the surface of a flower. These adaptations include sticky pads on the end of the leg (tarsal pads) or terminal claws. Unfortunately for the plant (which needs pollination) and the insect pollinator, pollen can stick to the pads and cause an insect to lose its grip. What is a poor insect pollinator to do? Use its claws with a little help from the plant.
Whitney & Federle* review the biomechanics of plant-insect interactions and note that many flowers have special “conical” cells on their petals. These cells provide an excellent surface with plenty of sites where insect claws can fit. Conical cells allow the pollen laden insect to land on the flower without slipping.
*Whitney HM, Federle W. Biomechanics of plant–insect interactions, Curr Opin Plant Biol (2012), http://dx.doi.org/10.1016/j.pbi.2012.11.008