In the United States, there are about 5,000 species of bees. On a global scale, there are approximately 25,000 named species, but perhaps as many as 40,000 different species. Bees comprise a highly successful monophyletic group derived from wasps and live in almost all terrestrial habitats within our region. By moving pollen around from flower to flower and plant to plant, bees perform vital and often unappreciated roles as the most important group of pollinating animals on earth. Most plants do not self-pollinate or benefit from the cross pollination with unrelated individuals that comes about through the foraging activities of bees.
Pollination is the transfer of pollen grains from anthers to a receptive female stigma.
Bees are the animal vectors that efficiently move the pollen within and between individuals of the same species. The vital roles that bees play in Sonoran Desert ecoysystems can be understood by thinking about what life would be like without them. Without the diverse assemblage of native bees living in our deserts, most of these plant and animal communities would collapse into a simpler assemblage of wind-pollinated species, with few or no fleshy berries and other fruits to sustain birds, mammals, lizards and other wildlife. Bees perform other vital ecological roles in addition to pollination . Most bees are ground-nesters so their tunneling activity aerates the soil and allows water from infrequent rains to quickly penetrate and reach plant roots.