GARDEN TOWER PROJECT > Pests and Pollinators > Introducing Native Hole-Nesting Bees to Your Garden (Crown Bees pt. 1) GARDEN TOWER PROJECT > Pests and Pollinators > Introducing Native Hole-Nesting Bees to Your Garden (Crown Bees pt. 1)

Introducing Native Hole-Nesting Bees to Your Garden (Crown Bees pt. 1)

GARDEN TOWER PROJECT > Pests and Pollinators > Introducing Native Hole-Nesting Bees to Your Garden (Crown Bees pt. 1)

How to Support Your Garden and Bee Community Without the Effort of Raising Honeybees

This is the first of three useful guest posts by our pollinator-supporting friends over at Crown Bees of Woodinville, Washington.

Planting a food garden is a labor of love. Gardeners put a lot of time and effort into the work of creating and maintaining a garden, but rarely consider the importance of pollination. We tend to take bees and their work for granted because bee populations have historically been robust and thriving.

Many gardeners wish they could raise honeybees to ensure their garden’s pollination, but raising honeybees takes a lot of time, money, and training. Some communities don’t allow honey beekeeping because of safety concerns. The problems facing honeybee populations are well known, and honeybees are not the only bees suffering due to habitat loss, pollution, disease, and climate change.

Planting a food garden is a labor of love. Gardeners put a lot of time and effort into the work of creating and maintaining a garden, but rarely consider the importance of pollination.

Female blue orchard mason bee covered in pollen.
Female blue orchard mason bee covered in pollen. Photo by Jacob Dunphy.

Alternative Bees to the Rescue

Mason bees and leafcutter bees are alternatives to honey bees on which gardeners can rely. They are superior pollinators, easy to raise, inexpensive, and most importantly, safer for children.

Blue orchard mason bees (Osmia lignaria) are one of North America’s 3,600 native bee species. (Honey bees, by the way, are from Europe.) Alfalfa leafcutter bees were introduced in the 1940s in order to save and maintain the alfalfa feed industry. Alfalfa leafcutter bees are now naturalized across North America. Both mason and leafcutter bees are solitary, hole-nesting bees that are superior pollinators which can be raised in gardens and farms.

Why Are Mason and Leafcutter Bees Superior Pollinators?

Honey bees carry wet pollen packed onto special hairy plates on their hind legs. Mason and leafcutter bees don’t have these special structures on their legs. Instead, they have special hairs on the underside of their bellies. Pollen is carried dry and loose on the large surface area of their hairy bellies, and pollen falls off easily at every flower they visit. One mason bee can carry out the pollination action of 100 to 200 honeybees!

Mason bees emerge in cooler, wetter, and windier weather than honey bees. Mason and leafcutter bees have a short flying range from their nests to flowers: only 300 feet. Mason and leafcutter bees are not picky about the flowers they visit. Because they are generalists, they are stay close to their home while they pollinate gardens and orchards. Almost every bee, except for a social queen, has a flying life span of about 4 to 6 weeks. Each solitary mason and leafcutter female bee has a feeling of urgency to get their parenting duties done and this makes them wake up earlier, stay out later, and fly in worse weather.

Male leafcutter bees have green eyes and golden hair.
Male leafcutter bees have green eyes and golden hair. Photo by Demarus Sandlin.

Are Mason and Leafcutter Bees Really Gentle and Easy to Raise?

Because they don’t have a colony, stores of honey, or pollen to protect, solitary bees are typically much less aggressive and don’t mind you watching them come and go to their nesting house.

Solitary bees overwinter in cocoons, making them easy to handle and move. The steps for raising mason and leafcutter bees are simple: set up the bee house and nesting materials, release cocoons, wait as they work, protect filled nesting materials, harvest cocoons, and repeat! There’s no need to feed and replenish honey stores in the winter since the bees are sleeping in their cocoons.

Because they don’t have a colony, stores of honey, or pollen to protect, solitary bees are typically much less aggressive and don’t mind you watching them come and go to their nesting house.

What are Solitary Bees?

Honey bees and bumblebees are social bees with only one fertile female bee in the colony. We all know social bees pretty well and we grew up learning about how they live. Actually, nearly all of the world’s 21,000+ bee species do not live in social structures. Non-social bees are called solitary bees and every solitary bee is fertile. Each solitary female bee lives and works on her own and she has all the responsibility to take care of her young.

A female mason bee rests in her nesting hole, a natural lake reed.
A female mason bee rests in her nesting hole, a natural lake reed. Photo by Tim Krogh.

What Are Hole-Nesting Bees?

About 70% of bee species build their nests underground and individual bees can share a main tunnel entrance. About 30% of bees nest in holes like an old grub tunnel in dead wood or the hollow of a branch or stem. We can’t raise ground-nesting bees very easily but we can raise hole-nesting bees because we can recreate their nesting holes, harvest their cocoons, and move them to where we need them. Solitary bees do not live in hives, instead we call the structures we build for them bee houses.

First, a female bee claims a nesting hole as her own and starts building nesting chambers in the back of the hole. Each nesting chamber is composed of a mix of pollen and nectar called a pollen loaf, a single egg, and a protective wall. Mason bees use moist, clayey mud to build walls between nesting chambers. Leafcutter bees build protective leafy cocoons, all in a line, with each cocoon separated by a layer of leaves. When the female is finished with one nesting hole, she protects the nest with a thick layer of nest building material called a “capped end”. These capped ends let us know that the bee house was used by a solitary bee.

Which Bees are Right for Me?

Mason bees emerge in the early spring when the weather is consistently warmer than 55°F. They are great pollinators of fruit and nut trees, as well as blueberry and strawberry bushes. Leafcutter bees emerge in early summer when the weather warms above 70°F. Leafcutter bees pollinate melon, squash, pea, summer vegetables, and flowers.

Both kinds of bees can be raised in the same bee house. Simply swap out nesting materials from mason bees and replace them with leafcutter materials. Mason bees prefer 8mm nesting holes and leafcutter bees prefer 6mm sized nesting holes.

Ensure Your Garden’s Pollination

Raising mason and leafcutter bees will help your garden grow a greater number improved fruit and vegetables. Many flowers need to be visited repeatedly in order to grow fruit at all. For example, a pear flower needs to be pollinated 30 times to make fruit! A flower that is properly pollinated will grow fruit that is rounder, fuller, and healthier. Adding a different bee species to your garden or farm can increase your yield by 24%! All of the effort that you put into your garden will be rewarded when you raise gentle solitary hole-nesting bees.

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