Making Homes for Wild Bees
Solitary cavity-nesting species such as mason bees are attracted to logs and dead trees, as well as hollow branches such as bamboo or sumac. Elderberry stems also are good because they have a soft pith that’s easily cleaned out. David Green of www.pollinator.com says don’t place elderberry stems out too late in spring because they also are susceptible to potter’s or mason wasps — although those are beneficial natives, too. Wild bees also will make their home in a suitable handmade dwelling, in a dead tree trunk, block of wood or bundle of tubes. Here are three easy-to-make bee homes:
Bundle together a dozen or so 10-inch-long pieces of half-inch-diameter bamboo or sumac that have been hollowed out at one end with a drill or awl. Stuff the bundle into a coffee can or piece of PVC pipe, and then wire it securely onto a tree branch or fence post.
A Nesting Block
Start with an 8-inch-long piece of untreated 4-by-6 or 6-by-6 wood post, or use a short log. Drill three-eighths-inch holes, 6 to 7 inches deep and at least 1 inch apart. Blacken the front of the block by placing it in a fire for a minute or two. Attach the block to a post or tree branch.
A Bee Stump
Drill into a tall existing tree stump, making 6-inch-deep, three-eighths-inch holes that are spaced 2 inches apart on the south and east sides of the stump.
A secure entrance is crucial, so holes about three-eighths inch in diameter are best. The tube-shaped holes also should be at least 6 inches deep, so you will need an extension bit for your drill. Several species can control the gender of their offspring, and they like to place female eggs deep in their burrows, with male eggs closer to the entrance. That way, males will be waiting when the females emerge. The holes should be closed at one end to ensure the safety of the eggs, too.
Early spring is the best time to put out new bee nesting blocks, because that’s when females are seeking new homes. Locate the nests at least 3 feet off the ground in a place where they will get warm morning sun and attach them securely so they won’t shake in the wind. Make the holes slope slightly upward so rainwater does not run into the holes. As summer progresses, you will know you have tenants if the holes or tubes become plugged with mud or debris.
Good Management of Carpenter Bees
If you spot a large bee buzzing around your home that looks like a shiny bumblebee without its fuzz, it’s probably a carpenter bee. These are some of the largest bee species and have a blue-black, green or purple metallic sheen. Male carpenter bees can be curious and fly close to humans, but they are completely harmless because they have no stingers. Females can sting, but they rarely do. Carpenter bees help pollinate numerous crops such as corn, pole beans, peppers and blackberries.
Carpenter bees (Xylocopa species) may want to share your home sooner or later if you have a wood house or a wood deck. Females bore half-inch-wide holes into wood and then excavate a burrow to raise their young, often reusing old nests year after year. They will burrow into dry wood wherever they can find it, but they prefer softwoods such as pine. The damage they do to the wood, however, is mostly cosmetic.
Extension entomologists unanimously agree that the best way to prevent carpenter bee damage is to keep wood surfaces painted (stains don’t deter them nearly as well as paint). Some people have good luck plugging bee entry holes with aluminum window screening held in place with duct tape. After a few weeks, remove the duct tape and fill the hole with wood putty.
“Carpenter bees are very selective of their nesting wood,” says James Tew of Ohio State University’s Honey Bee Lab. “If only a few boards are being targeted and the plugging trick doesn’t work, consider replacing those boards and hope that the new ones are not as attractive.” But because carpenter bees are beneficial, make sure they have wood available that they can use. That way, both you and the bees are happy.
Pollinator Bee Resources
The Xerces Society
Xerces offers fact sheets on pollinator conservation and also sponsors programs to safeguard the diversity of native insects.
The University of Georgia’s Honey Bee Program
Has excellent guidelines for creating a permanent pasture as habitat for native bees. Click on “Establishing a Bee Pasture.”
Offers books and supplies for managing mason bees, including well-made bee houses and other bee-related products.
The Pollination Home Page
This Web site is a labor of love by South Carolina bee man David Green, with links to bee information, projects and regional wild bee expertise.
International Pollination Systems
Commercial providers of leafcutter bees. The Web site is rich with wild bee information.
For additional information, see "Protect Your Pollinators".