Leafcutter bees

Leafcutter bees are polite gatherers who only take what they need, and do not endanger plants through their work.

The average human lifespan is unfathomable to most garden dwellers. In the case of many insects, their adult forms are short bursts of activity finely tuned to a specific time of year.

Mason bees, for example, are generally active in the spring. The few weeks that they are alive and flying as adults are filled with trips to flowers on their preferred plants, including maple and apple. As spring transitions into summer and then into fall, the insects in a landscape also transition accordingly.

As the days of summer begin to get long and hot, heat-loving insects emerge from their various hiding places to bask in the sun. In the realm of solitary wood nesting bees, who typically live alone in holes bored into dead trees by beetle larvae, leafcutter bees take up the mantle of being the main summertime bee.

Leafcutter bees are commonly seen and incredibly varied in their appearance. However, this large group of bees all share some unique methods of making their nests and gathering pollen to feed their young.

Like mason bees, leafcutter bee females spend their lives provisioning nests with food in order to feed their young.

After finding a suitable tunnel already burrowed into wood, a leafcutter bee will gather a ball of pollen and lay an egg on top. She then closes the egg into its own protected room, leaving it to consume the pollen and grow over the following winter and spring. Leafcutter bees, in accordance with their name, create partitions between their young using sections of leaves that have been skillfully trimmed from the local foliage.

Some species even use leaf sections as a type of wallpaper, lining their nests in order to ward off fungal invasions. The leafcutter bees in my area seem to prefer using my Virginia Sweetspire for their nests. They are not very picky, however, and can utilize cuttings from a wide variety of plants. It is usually easy to tell if you have active leafcutters in your landscape, as the semi-circular cuts they make in leaves are very distinct. Leafcutter bees are polite gatherers who only take what they need, and do not endanger plants through their work.

Leafcutter bees are efficient pollinators of a wide variety of native summer blooms.

They can easily be seen on almost anything that blooms, especially if you know what to look for.

My preferred method of bee identification comes from noted bee enthusiast Sir Mix a Lot – if you are unsure about what type of bee you see, first look to the butt. Most leafcutter bees utilize lush hairs on the underside of their abdomen in order to gather pollen.

As they belly-flop from flower to flower, these bees tend to hold their abdomens straight up in the air in order to hold on to as much as possible. They also generally have abdomens that are very angular in appearance.

In short, if you see a bee with a sharply triangle-shaped butt that it’s holding high in the air, it is most likely a leafcutter bee. This is of course not always the case; there is a leafcutter residing in our mountains that takes on the appearance of a small bumble bee, for example.

Leafcutter bees are able to live in man-made housing for wood nesting bees; however, there are also some other easy things you can do to encourage them to settle down in your area. Leave standing dead trees where they are whenever possible, and also try to leave as much fallen dead wood on your property as you can. This can go a long way in fostering your native leafcutter bees.

Brannen Basham and his wife, Jill Jacobs, operate Spriggly’s Beescaping, a business dedicated to the preservation of pollinators. Contact him at brannen.basham@gmail.com.