Despite being a critical pollinator for a variety of crops including fruits, wildflowers, and veggies, some gardeners still view a leafcutter bee as a pest.
Ones can easily recognize the existence of this insect in their garden by noticing cuts that appear like a half-moon on the leaves of their shrubs or rosebushes.
Similar to honey bees, a few species of this insect make a great commercialized pollinator as well.
Osmia spp. is among the popular species when it comes to commercial pollinators. You can find them utilized to help the pollination of blueberries, alfalfa, and carrots.
How Leafcutter Bees Look Like
Having a moderate size, a leafcutting bee is pretty similar to its cousin that is ranging from 0.19 to 0.94 inches.
Its color is mostly black and it comes with a portly body that makes this bee different from others.
Exclude the parasitical species called Coelioxys, the females of leafcutter bees have a different way of transporting pollen.
If other bees tend to have pollen on their back legs, this species typically take it on their furs that locate on the bottom of the belly.
You can tell that this bee is having pollen when the bottom of its abdomen shows a color of yellow to profound gold.
The male leafcutting bee is typically tinier than the female.
Aside from its smaller body, you can identify it through its lengthy antennae and pointless sharp belly.
Meanwhile, the female comes with a triangular-shaped abdomen and even has teeth, making it different from other bees.
Compared to most bees, the leafcutting acquires a bigger head since it has additional muscles that develop to help this insect chew through the foliage.
Leafcutter Bee Life Cycle and Reproduction
The life cycle of male and female leafcutting bees is different although both come up in the spring to mate immediately.
While the females begin to find an appropriate space for raising a family, the male bees typically are not alive much longer.
Once there is sufficient foodstuff, the mother leafcutters will lay an egg on the upper side.
Before that, the mother leafcutter will construct a bee loaf to supply enough food for the next generation from egg to full-grown size.
Then, the mother will repeat the activity of creating bee loaves, producing eggs, and form divisions until the whole nest hollow is full.
As the mother successfully forms an ultimate, thicker wall, she will shortly die.
Meanwhile, the larvae can still feed on the nectar and pollen that she left behind in the nest.
Then, the next generation will metamorphose into a full-grown bee that stays dormant, waiting for the upcoming spring to come.
When chewing its way out of the nest, the adult leafcutters will mate and are ready to repeat the above life cycle.
The Distribution of Leafcutting Bees
Scientifically known as Megachile spp., you can easily find this bee in North America since it is a native pollinator that is pretty common there.
You can find around 242 species of leafcutters in this region.
Florida is where around 63 assorted species of leafcutter bees live. There are even more than three subspecies there.
Osmia, Lithurgus, Heriades, Ashmeadiella, and Coelioxys are among the several genera of these bees that you can find in Florida.
This bee is a part of a bigger unit that includes other leaf-cutting species as well, such as mason bees.
Not only common in North America, but the distribution of leafcutter bees currently also includes everywhere around the world.
Leafcutting Bee Behaviors
Similar to wasps and honeybees, leafcutting bees are solitary insects as well. However, unlike their cousins, they do not reside in big colonies or groups.
Since it is a solitary bee, each mother of the leafcutters will handle her brood only instead of minding the others.
Some of them may create little colonies, but it does not mean that the leafcutters are genuinely social.
When leafcutter bees build a small colony with others, they will share the opening of their respective nesting sites only.
Nearly all species of leafcutting bees spend their winter time in their nest as newly formed full-grown.
Throughout the spring, they will go out from the home by chewing it.
Unlike bumblebees or honeybees, leafcutters typically do not guard their nesting sites sharply.
They will not sting unless being handled and are not a prickling danger for people. Compared to honeybees, their sting is less torturing as well.
The Enemies of Leafcutter Bee in Nature
While these bees have the behavior of cutting a variety of crops’ leaves, their lives are not as easy as they may seem.
Leafcutter bees have some natural enemies that tend to attack their nests. A lot of parasitoids like wasps and flies are among the assailant.
Crematogaster spp. which is a kind of ant is another popular natural foe of leafcutter bees too.
Cleridae, Meloidae, and some other beetle species also become their opponents in nature.
One of the genus inside their family, the Coelioxys, does not have a mutually beneficial relationship with leafcutter bees as well.
The Coelioxys likes to lay its eggs in leafcutting bee’s nests.
This species, especially the young one, typically steals the kept pollen of others too, making it popular as a kleptoparasite.
Leafcutter Bee House Source and How It Is Build
Leaves that it cuts from a plant are not the food source of a leafcutting bee. Instead, it uses the foliage to create nest cells for the baby.
This bee cuts clean around 0.25 to 0.5 inches of leaves in round shapes and forms the pieces into something named nursery assembly that the female utilizes to lay eggs.
It is safe to say that the nest resembles a cigar and there are some cells in the nesting site.
Meanwhile, each cell in the nest chamber holds a ball of accumulated pollen and nectar that the female of leafcutter bees leave behind.
Aside from the kept pollen, every cell also has a single egg. As a result, each of them will generate one bee.
Leafcutter bee itself takes advantage of nearly all leaves from various broad-leafed plants to build their nesting sites.
In addition to foliage, several species of leafcutter bees also utilize flower petals to create the nest.
The host plants of leafcutter bees include redbuds, azaleas, bougainvillea, roses, and other ornamental varieties that acquire sleek foliage.
Plant stems and soil are the most common places where leafcutter bees build their nests.
Hollow created by other insects in vegetation makes another good place for them too.
Leafcutting bees also use holes in concrete walls and a range of other hollows for their nesting locations.
The Importance of Leafcutting Bees in the Garden
It is no secret that leafcutting bees are crucial in the ecosystem of your garden since they make one of the greatest pollinators.
Commercial agriculture even takes advantage of a range of different leafcutter species to assist the pollination of their crops.
Leafcutter bee makes pollination go well thanks to its habit that carry pollen on its bellies.
As a result, the spore can detach effortlessly and pollinate your plants as this insect moves back and forth between the crops and their nesting sites.
Moreover, you can easily invite leafcutting bees into your garden.
Thanks to its non-aggressive defense behavior, it offers a simple coexistence between pollinators and gardeners as well.
Building a bee hotel will promote the leafcutter to come into your garden.
You can easily find some tutorials to create this nest housing with a variety of designs available online.
Reasons to Consider Leafcutting Bees as Pests in Your Garden
You may overlook the appearance of leafcutter bees until they leave some notches in your ornamental plants.
The cuts are typically harmless to plants, but these can reduce the aesthetic value of your favorite shrubs and rosebushes.
Different from other pests like grasshoppers and caterpillars, leafcutter bees do not feed on your plants’ foliage.
As a result, using insecticides typically does not give an effective result for keeping leafcutter bees at bay.
Instead, you should try creating material obstruction by using something like cheesecloth on the affected plants.
This preventive solution is pretty efficient when you do it immediately after leafcutting is initially observed.
Recommendations to Manage Leafcutter Bee Nest in the Garden
To decrease the number of leafcutter bees in your garden, you may need to get rid of their nesting places.
Plants with thick stems and recessed openings like bamboo and roses are one of the most common locations utilized by leafcutting bees to build a nest.
Using wax to seal cropped ends can help to avoid leafcutting bees nesting in rose canes.
Aside from wax, you can also take advantage of white glue, wooden fastener, or thumbtacks as a sealing solution.
Brushed, rotting wood is another favorite spot for leafcutting bees to build their nests.
The insects typically use tiny holes the size of a coin or something tinier for the nesting site.
You can tell that there are leafcutting bees’ nests in the wood when the opening is stuffed with brown or green foliage.
Above all, the leafcutters can be irritating for gardeners who grow ornamental plants, but it becomes a good friend for those who cultivate crops.
It will depend on you whether to invite this leafcutter bee or get rid of it instead.