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. In addition to this bioturbation , their nitrogen-rich feces serve to fertilize the soil. The bees themselves, often provide nutritious food for other animals including lizards, mammals, birds, other insects, spiders and other arachnids. In their daily searches for pollen and nectar from flowering desert annual wildflowers or perennials, bees harvest great quantities of these floral rewards as food for themselves and their larvae. The pollen contains the plant gametes but are a rich food source of amino acids, proteins, fatty acids, vitamins, minerals, sterols and carbohydrates for bees.