ean honey bee (Apis mellifera) is the most important crop pollinator in the United States. However, because of disease and other factors the number of managed honey bee hives in the United States has declined by 50 percent since. During this same period, the amount of crop acreage requiring bee pollination has continued to grow. This makes native pollinators even more important to the future of agriculture.
Native bees provide free pollination services (as opposed to honey bee which are typically rented) and are often specialized for foraging on particular flowers, such as squash, berries or orchard crops. This specialization results in more efficient pollination and the production of larger and more abundant fruit from certain crops. The pollination done by native bees contributes an estimated $3 billion worth of crop production annually to the U.S. economy.
Native bees come in a wide range of colors and sizes, from tiny sweat bees less than a quarter of an inch long to bumble bees over an inch in length. Most are solitary, with each female creating and provisioning her nest without the support of a caste system of workers.
About 70 percent of native bees excavate underground nests while 30 percent of bees nest in wood tunnels, usually pre-existing holes such as those made by wood-boring beetles, but some will chew out the center of pithy twigs. In the case of both ground-nesting and wood-nesting bees, once the nest is complete, the mother bee generally dies. Her offspring will remain in the nest, passing through the egg, larva and pupa stages before emerging as an adult to renew the cycle. For some species this life cycle may progress over a matter of weeks, resulting in a second generation of bees in a single season. A few species may remain dormant for over a year. Most solitary bees however complete this life cycle over the course of a full year.
Native bees often only live for a few weeks as actively flying adults. They mate immediately upon emergence and the females begin nesting. They lay relatively few e