Leafcutter Bees: A Beginners Guide

What are leafcutter bees?

Leafcutter bees are solitary bees. This means that they live alone and not in a hive, like honeybees. They make use of natural tree cavities to lay their eggs in and use leaves and flower petals as nesting materials. Hence their name; they cut small semicircles off of leaves. However, they rarely do damage to plants. The leaves they cut are used to create nursery chambers for their eggs. Think of this like a protective incubator made out of leaves, filled with nectar and pollen that will feed the egg as it develops into an adult bee.

During the process of gathering food supplies for their young, leafcutter bees pollinate your garden. As they forage flowers, pollen sticks to their hairy abdomen. While making their way back to their nesting places, some of these pollens will fall off their hairs onto different flowers, cross-pollinating them. They are such effective pollinators that they can double (sometimes even triple) your yield!

Life-Cycle of the Leafcutter Bee

Leafcutter bees make their entrance into the gardens when temperatures reach a consistent 24C and the summer flowers are blooming. They will chew their way out of the nursery chambers they overwintered in and emerge eager to have their first sip of nectar. Soon after emerging they will mate and start working on their nests; gathering leaves, flower petals, nectar and pollen. Slowly, over the next couple weeks she will create approx. 15 nesting chambers that contain the new generation of leafcutter bees. Your bee house is the perfect place for her to lay her cocoons in. Unlike mason bee eggs, some of these eggs might hatch in the same season that they’re laid in. In early fall you’ll start noticing a decrease in leafcutter bee activity in your garden. The eggs will no longer develop and will stay inside their nursery chambers during the winter.

leafcutter bee

Note: Next, we’ll tell you how to harvest and incubate leafcutter cocoons. If this is the first year you host them and purchase cocoons from a store, there is a good chance that they’re already incubated. If this is the case, they should be placed directly inside the bee house upon purchasing them! There is no need to incubate your bees the first year.

How to harvest leafcutter bee cocoons

If you host mason bees, you’re used to taking apart the nesting tubes in the fall to harvest cocoons. This is not what you’ll do with leafcutter bees! After you notice there is no longer any activity, it’s time to take your bee house inside. This will prevent wasps and woodpeckers doing any damage to them. The tubes (or nesting trays), that contain the leafcutter bee eggs, will stay intact during the winter. The filled tubes have been capped with leaves to provide a safe and warm home during the colder months. Store the tubes with the leaf-capped ending facing up in a garage or shed for instance (in a cool place, but do not put them in the fridge!). You can place the entire tube or nesting trays inside an organza or BeeGuard bag for extra protection from pests.

Around the time that the dandelions begin to grow, is when you’ll start preparing to put your leafcutter bees outside. You start by harvesting last-years leafy cocoons from the nesting tubes or trays that you stored over the winter. It’s quick, easy and allows you to check for pests and document your bee population. How to harvest your leafcutter bees:

Step 1: Break open the nesting tubes. If you have natural reeds, pinch the end that the bees have capped with leaves, and carefully pry apart the reed, being very careful of the cocoons inside. Paper reeds can be unraveled and most nesting trays can easily be opened with the help of a screwdriver or popsicle stick.

Step 2: The leafy cocoons are now exposed. Carefully separate the cocoons from each other and place them in an organza or BeeGuard bag. You will store them in this bag during the incubation period.

How to incubate leafcutter bees

Step 1: Place the organza bag that contains the cocoons in a dark warm room. For instance, the room where your water heater is located. As they overwinter as eggs inside leafy cocoons, they have to be warmed up to start developing into adult bees. This is what we call the “incubation” period. It’s not the same as incubating eggs, where you place them in an incubator. Instead, we’re trying to simulate warmer outside temperatures.

Step 2: Check periodically if any bees have emerged from their cocoons. At a temperature of 30C, the adult bees start to emerge approx. after 20 days. At a lower temperature of 21C it will take them around 42 days to emerge. Tip: Try to time the release of your bees with the blooming period of your summer flowers.

Step 3: When the first bees emerge, it’s time to put them and the other unopened cocoons outside in your bee house! Place them in the open attic above the tubes, not in the tubes themselves. If your bee house doesn’t have an attic, you can put the cocoons in a small cardboard box (tea box) with an opening on one side and tape it to your house.

FAQ

While many gardeners think of leafcutter bees as a pest that eat their plants, the opposite is actually true. They can be a great addition to vegetable and flower gardens! Many vegetables, fruits and flowers depend on cross-pollination, which is exactly what this bee does. Gardeners have noticed a significant increase in their yield while hosting leafcutter bees. Besides that, hosting these gentle bees is a great way to support pollinators and teach your kids about natures beauty.

Leafcutter bees are important for pollinating tomatoes, alfalfa, blueberries, carrots, fruit trees, Phacelia, Dahlias, Bluebells, Sunflowers, mints, peas, beans, onions and many wildflowers. Often, the plants that they pollinate are not the same plants that they cut pieces of leaf off.

Summer leafcutter bees prefer 6mm nesting holes.

We recommend one nesting hole per 2 leafcutter bee cocoons. They are known to disperse more than mason bees, which is why the number of cocoons you receive per order is higher. For mason bees we recommend 1 nesting tube per 1 bee cocoon.

Non-hairy and thin leaves are preferred by leafcutter bees to make their nursery chambers. For instance, leaves from roses, plums, cherries, clematis, clarkia, hawthorns, cosmos and mountain ash.

Foraging flowers is a big part of what leafcutter bees do on a day-to-day basis. They visit tons of flowers to gather pollen and nectar to place within each nursery chamber. They particularly like nectar-rich and easily accessible flowers like sunflowers, cosmos, bluebells, mint, phacelia and open-centered dahlias.

Due to not having any honey to protect they are known as gentle, non-aggressive bees. However, female leafcutter bees do have a stinger and will use it when handled roughly. A sting from a leafcutter bee is closer to that of a mosquito than it is to a honeybee.

No, leafcutter bees do not make honey. The main reason for hosting them is cross-pollination and supporting pollinators.

At Country Bee Honey Farm we sell incubated leafcutter bees for $27.95 per package in our store. Each package contains 100 bee cocoons. The bees that we sell are already incubated and have to be placed inside your bee house within two days. To make sure we have enough bees for everyone you can pre-order them. As you place your order you will receive a pick-up date.