Ask most people to describe a bee, and they will identify the common honeybee (Apis mellifera). well known as producers of honey and as the livestock of commercial pollinators, honeybees have also been in the news lately because of the to Colony Collapse Disorder.
Commercial beekeepers have returned after winter to hives they maintain and find them practically empty, containing only the queen and some immature larva. As scientists try to figure out the causes of CCD, farmers and home gardeners have embraced native bees to make up for the decline in the honeybee population.
Native bees are considered better pollinators because they work longer days than honeybees. there are thousands of native species, but the two most well known are the bumblebee (Bombus spp.) and carpenter bee (Xylocopa spp.).
The bumblebee is one of the only social native bees. they live in annual colonies that are established in spring by lone queens. they are most easily recognized by their large size and hairy abdomens.
Carpenter bees are commonly mistaken for bumblebees, but they have shiny abdomens. Although carpenter bees are most famous for their drilling and chewing into hardwoods, they are important pollinators. if possible, discouraging their drilling before it happens is a better solution than killing the bees after they have drilled.
Both bumblebees and carpenter bees work earlier in the spring than honeybees and are important pollinators of bramble and blueberry crops. both species are occasionally found sleeping on flowers if they don’t make it back to their nests.
There are three other native bee species that are commonly seen in Pennsylvania gardens: the blue orchard mason bee, leafcutter bee and green metallic sweat bee.
Blue orchard mason bees (Osmia lignaria) are friends of apple and cherry farmers because their activity in early spring coincides with that of these fruit blossoms. they can be invited into a garden by creating nesting blocks made from a block of untreated wood drilled with 5/16-inch diameter holes.
Leafcutter bees (Megachile spp.) chew distinct semi-circular cutouts of the leaves of roses, redbud and lilac. while this causes cosmetic damage to the plants, the plants will survive; there is no reason to treat for these effective pollinators. not all leafcutters are natives. An introduced species that is essential to the alfalfa industry is appropriately named the alfalfa leafcutter bee. These bees carry the pollen they collect on the underside of their abdomen.
Green metallic sweat bees (Agapostemon virescens) are actually not attracted to sweat. However, they are close relations of sweat bees (Halictus spp.), which are attracted to sweat. Most have a bright green head and thorax, and their abdomen has black and yellow stripes. Nesting in burrows in the ground, they are not aggressive and rarely sting, unlike yellow jackets or other ground-nesting wasps.
All bees, whether they are native or introduced, are essential pollinators which can benefit from simple actions. Protect them by implementing the three P’s of pollinator protection:
• Planting native plants
• Providing housing
• Pesticide reduction around the house and garden
Planting native plants provides bees with nectar and pollen. By planting natives with different blooming periods bees can be supplied with nectar and pollen from spring until fall. Native plants are more effective at attracting native bees and provide more nectar than some of the ornamental exotic varieties.
Providing housing is quite a simple task and can easily be accomplished on a winter day. Housing designs include drilling 5/16-inch holes in logs or untreated lumber, or rolling 5/16-inch tubes out of parchment paper. The Penn State Extension website (http://extension.psu.edu/) has designs for both blue orchard mason bee homes and also bumblebee homes.
Pesticide reduction is the final way to protect pollinators. Spray in the evening when pollinators are least active, and avoid spraying flowers with pesticide. Also, switch to organic pesticides such as insecticidal soap or spinosad, to leave less pesticide residue in the environment. both of these organic sprays break down more rapidly than their synthetic counterparts.
By following the three P’s, homeowners can increase the welfare of their natural communities. More information on pollinators, plans for bee homes and ways to certify your garden as pollinator friendly can be found on the Penn State Extension website and those of the Pollinator Conservancy (www.pollinator.org) and Xerces Society (www.xerces.org/pollinator-conservation.
Remember this: Don’t wince when you see a bee. Cherish it.
Philip Bauerle is a summer intern at Penn State Extension. Columns by extension staff or master gardeners will sometimes appear in place of the Garden Q&A by Sandy Feather, a Penn State Extension educator. first published on September 17, 2011 at 12:00 am