The planet’s best pollinators are in big trouble. Wildflower meadows where native bees once gathered nectar and pollen have turned into shopping malls, and dead trees where these ancient insects nest are getting harder to find. The native bees that do manage to survive are imperiled by Big Ag’s pesticides — unless they can find safe haven in diversified organic gardens.
The Fruits of Their Labor
Gardeners can reap huge benefits from hosting helpful pollinators, which tend to stay put when given food and a place to live. Native bees — including bumblebees, sweat bees, mining bees and others — pollinate many crops more efficiently and completely than honeybees do, with strawberries, blueberries and the entire squash family reliant on local pollinators to produce their best crops. Tomatoes visited by bumblebees bear bigger fruits, because the big bees’ buzzing action shakes loose more pollen than wind alone. Strawberries pollinated by multiple types of bees yield fewer misshapen berries, and pumpkins pollinated by native squash bees produce larger pumpkins. Pollinators play a significant role in producing 150 food crops in the United States and, according to the Xerces Society (a nonprofit wildlife conservation group), one in three mouthfuls of our food and drink requires their work.
For about 70 percent of the 4,000 bee species native to North America, home is a secure spot tunneled into the ground (ground nesters). The other 30 percent nest in dead trees and stems (wood nesters). Almost all native bees live alone, not in colonies. Passive by nature, bees won’t usually sting unless squashed or pinched.
Young adult bees emerge from their nests at various times during the year, usually in sync with the blooming period of their favorite crops. Females quickly mate and select good nesting sites, which are often within 1,000 feet of desirable flowering plants (see “Plants That Attract Bees,” later in this article). After making a few short flights to learn their new addresses, ground-nesting bees immediately start working to excavate a nest and stock it with eggs. Gathering the necessary pollen, nectar and sometimes mud requires thousands of trips between flowers and the nest. The closer the flowers are to the bees’ nest, the less energy the bees must expend in flight.
Types of Native Bees
Native bees are closely tied to their environments. The following five types provide pollination for gardens and orchards.
Bumblebees are the largest native bees, and they also tend to fly the farthest in search of food. Active from spring to fall, they pollinate a wide range of plants and are especially important to legumes. Bumblebees usually nest in the ground or in cavities in trees. Bumblebees are the only native bees that are truly social. [external_footer]