No known bees are nectar specialists; many oligolectic bees will visit multiple plants for nectar, but there are no bees which visit only one plant for nectar while also gathering pollen from many different sources. Solitary bees are often oligoleges, in that they only gather pollen from one or a few species/genera of plants. A very few species of solitary bees are being increasingly cultured for commercial pollination. Some solitary buy honey bees cheap have very advanced types of pollen carrying structures on their bodies. Often it is mixed with nectar to form a paste-like consistency. Solitary bees are important pollinators, and pollen is gathered for provisioning the nest with food for their brood. They are immune from acarine and Varroamites , but have their own unique parasites, pests and diseases.