How to attract native bees

ProvidedMason bees plug bamboo tubes with mud.

Our dog is declining.

His back legs have become half-cooked noodles. Unfortunately, he still thinks he can run. He’s still a good boy, happy to see us and always hungry. He just needs a little support. His doggy chariot will arrive next week. Sometimes nature needs some assistance.

In the past decade, honeybees have been declining. A condition called colony collapse disorder, or CCD, has drastically reduced their populations. Current research attributes malnutrition, pathogens and parasites to the disorder.

Neonicotinoid insecticides, often referred to as neonics, also are implicated due to their systemic nature. Imidacloprid, sold as Merit, is the primary neonic under fire.

However, not all researchers are convinced neonics are the problem.

J.C. Chong, an entomologist at Clemson University, believes that imidacloprid plays no or a very limited role in CCD. For more information, he directed me to scientificbeekeeping.com for research.

Honeybees are essential to pollination, in particular when it comes to fruits and vegetables. To assist nature, many enthusiasts host hives in their backyards for pollination purposes and honey harvest. Charleston Area Beekeepers Association, Charleston Community Bee Gardens and Lowcountry Beekeepers Association are leading the charge.

The severity of CCD has given attention to other pollinators, in particular native bees. The honeybees are non-native, introduced from Europe in the 1600s. Native bees are hardworking insects that start early and stop late in the day. Of all the native bees, bumblebees are the only social ones. They form small colonies but only the queen survives from year to year.

The majority of native bees are solitary nest-builders that lay eggs in the ground, holes in wood or hollow stems. Like most bees, natives are non-aggressive.

The Clemson organic farm at the Coastal Research and Education Center, a 5-acre research plot, has recently been investigating pollinators, in particular specific species and methods to attract them. Diverse flowering plants are kept in drainage ditches and surrounding areas and wildflowers will be interplanted with watermelons to improve pollination.

You’ve likely witnessed native bees without realizing it. Adults are generally active for a month during the spring to mate, lay eggs and gather pollen and nectar. Ground-nesting bees prefer bare soil or thin turf, leaving small mounds around a hole. They can be mistaken for yellow jackets, an aggressively stinging wasp, but ground-nesting bees are harmless.

Sweat bees are noted for their metallic blue/green colors. Recent research at the Clemson organic farm indicated their presence was significantly higher than all other pollinators. They gather pollen on the long hairs along their hind legs.

The mason bee is one of the more popular pollinating native bees. They frequently lay eggs in naturally occurring tubes and plug the entrance with mud. The males die shortly after mating. The female gathers pollen to prepare nests where an egg is laid in a chamber and sealed with bee bread, a food source left for hatching larva.

Simple nesting blocks can be constructed to attract mason bees. Multiple holes are drilled into blocks of wood several inches deep and vary in diameter from 1/4 inch to 1/2 inch. An easy approach is to use untreated lumber or dried logs that are about a foot long that can be stacked with the holes drilled in the ends.

Another approach is to use hollow tubes, such as 12-inch sections of bamboo. These can be artfully bundled with twine or placed in a cylinder. Once a mason bee lays eggs, she will plug the end of the tube with mud. A local mud supply will aid nest building since the adults forage nearby.

Nests need to be managed to avoid parasites and pathogens. One approach is to line wood block holes with paper tubes (crownbees.com) that can be changed annually once the adults hatch. Bamboo shoots can be swapped with new ones.

The nests can be arranged in a frame and placed about 4 feet above ground where it will receive morning sun. Some recommendations suggest that it should be protected from rain to reduce rot.

Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback, e-mail him at tony. bertauski@tridenttech.edu.