Get To Know Leafcutter Bees
The alfalfa Leafcutter Bee shows us how good a bee can be! A genial, efficient, tireless pollinator, the alfalfa Leafcutters became heroes in the first half of the 20th century when they saved the declining alfalfa seed industry. Alfalfa is a source of high protein for livestock in pasture. Hay mixes and seed production had decreased when pollinating bees lost their habitats to agriculture and land clearing. The loss of alfalfa was threatening a major food nutrient for livestock. Enter the Leafcutter to save the crop! Today, the alfalfa Leafcutter is still used extensively to pollinate this crop, and others.
Leafcutter bees are great pollinators
The Leafcutter Bee is a productive pollinator for summer gardens and flowers. The female carries pollen on the underside of her hairy abdomen, and then scrapes the pollen off within her nesting hole. Because the pollen is carried dry on her hair, it falls off easily as she moves among blossoms. This results in significantly more pollinated flowers than her cousin, the honey bee, who wets the pollen so it sticks to the legs during transport to the hive.
A gentle bee is the leafcutter bee
All Leafcutters Bees are solitary, meaning each female is a queen who does all of the chores. She can’t gather pollen/nectar, lay eggs, cut holes in leaves for her nest, AND defend her hole… so she doesn’t. The Leafcutter Bee is extremely gentle and allows you to confidently get inches from her nesting hole without fear of being stung.
Low cost investment
It doesn’t take much money or time to raise Leafcutter Bees. Nesting holes, housing and bees are quite affordable, and come in a variety of price ranges. Also, there is no need for protective gear, since they rarely sting, nor expensive equipment to buy.
In terms of time, plan about 15 minutes to select a location and set up your house. Warning! When your bees emerge and start pollinating, you’ll have to set aside time to observe them. Time flies as you watch them laying eggs for next season’s bees!
In late August, after bee activity stops, store filled nesting holes (open ends up) in an unheated garage or shed that is dry and secure. This will protect them from pests. Overwinter bee larvae in the nesting holes until next summer. That takes about 10 minutes. In just 1 to 2 hours a year of your time, you’ll get a healthy garden yield and amazing garden companions.
A bonus is that you’ll typically increase your bee cocoons from when you started.
Keys to Successfully Raise the Leafcutter Bee
1. Place your house with nesting material facing the early morning sun. The warmth wakes your bees earlier to start pollinating. Follow the setup instructions.
2. The Leafcutter Bee seals each egg with cut leaf bits. If she can’t find the right type of leaf (like the non-fibrous rose or lilac leaf) to cut and carry in her legs to the nest, she’ll leave your yard and set up her home elsewhere. This is the number one problem people face. Compare what rose leaves look like in comparison to other leaves in your yard. Not too thick, nor too thin, and with few veins.
3. Store filled nesting holes (open ends up) in an unheated garage or shed that is dry and secure, after bee activity stops. Overwinter bee larvae in the nesting holes until next summer. Leaving them outdoors exposes them to pests and weather elements.
Leafcutter Bee Quick Facts
Cavity dweller that uses existing holes
Leafcutter Bees are cavity dwelling bees that lay their eggs in existing holes. They do not create holes or damage structures to make holes. Leafcutter Bees stay close to home, foraging for pollen and nectar within 300 feet (100m) of the nest. This proximity makes them an attractive pollinator for summer yards and gardens. There are more than 130 species of spring and summer solitary bees in North America alone.
Solitary but likes neighbors
All female Leafcutter Bees are solitary queens. Each performs all of the duties that an entire honey bee hive might undertake: gathering pollen and nectar, laying eggs, and ensuring her eggs are protected when she’s not there by sealing them with cut leaf bits. Leafcutter Bees appear to like company because they build their nests near one another. There is no sharing of nests, however.
Since each female performs all the duties, she doesn’t have time to also defend her nesting hole. Therefore, there’s no need for aggression. Although Leafcutter Bees have stingers, they will only sting if their life is threatened. More times than not, stings are caused by being caught in clothing and bee feels it is being squished. Even if you are unfortunate enough to be stung, the effects are generally no worse than a mosquito bite. In fact, you are more likely to be bit by their mandibles before you will be stung.
She does have a couple of built-in defenses for her hole. She seals each egg chamber with cut leaf bits to protect her eggs from predators while she is away. Also, once she claims a hole, other Leafcutter Bees will honor it. She might visit someone else’s hole by accident while looking for hers, but she won’t lay eggs anywhere but in her own home.
Comparing a Leafcutter Bee to a Honey Bee
Description of Leafcutter Bees
- The gentle alfalfa Leafcutter Bee is black with pale yellow strips on the abdomen and face. It’s about 2/3 the size of a honey bee.
- These bees are solitary, with each female a queen doing all of the chores. The males will fertilize the females and then die within two weeks.
- Leafcutter Bees are cavity nesting bees, and readily use appropriately sized holes to nest in. They use sections of cut leaves to place their gathered pollen and egg in.
- In general, they emerge later in the summer when temperatures are in the 80°’s F (25°’s C).
- The alfalfa Leafcutter Bees got their name by their superior capability with pollinating alfalfa. Their scientific name is Megachile rotundata.
- Like the spring Mason Bees, they carry the pollen on their hairy abdomens which has much of the pollen falling off with each flower they land on. As a result, they are GREAT pollinators!
- The nesting range for these bees is about 300′ (100m) from their nest.
Watch this video to see a Leafcutter creating an egg cell. It was produced by Toronto’s “Resonating Bodies” outreach projects.
Content courtesy of Crown Bees