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Most people are likely familiar with honeybees, but perhaps not so much with leafcutter bees. Wild bees and other bees such as mason bees are also not a household name as their counterparts, the honeybees. And did you know there are about 25,000 different kinds of bees out there, out of which about 4,000 comprises wild bees, with about 400 of them not yet assigned any known names? Well, that is correct and it is apparent only honeybees are enjoying full glory when it comes to the recognition of bees for their pollination services. This is all happening at the expense of all these other kinds of bees.
Leafcutter bees are among North America’s top pollinators and there has been an increased use of these pollinators in commercial farms such as blueberry and alfalfa plantations. In this article, we dive deep into the world of leafcutter bees and will explain how to raise them.
About Leafcutter Bees
Leafcutter bees are stout-bodied, medium-sized black bees whose sizes range between 5mm to 24mm. They are found throughout the world and are a common sight in North America. In total, there are 63 different species of leafcutter bees in the Americas.
The name leafcutter bee is derived from their behavior that involves neatly slicing off pieces of leaves that they use in constructing their nests. These ingenious bees make cigar-shaped nests that usually house several cells that hold their young. Within the cell is a ball-shaped food reserve or loaf made of pollen that will sustain the growing larva until the time it will emerge as a grown bee. It is worth mentioning that each of the cells will host a single egg. The nest can be almost anywhere desirable, which could be wood crevices, plant stems, or holes in the ground. Leafcutter bees can also utilize dead snail shells or holes in walls.
Leafcutter bees utilize broad-leaf deciduous plants when constructing their nests. Some of its species will even use plant resin and petals when making their nests. You can find some circular leafcutter bee cuts on the leaves of plants such as bougainvillaea, roses, redbud, azaleas, and ash. They tend to prefer smooth and thin leaves.
The nests built by leafcutters will house their young ones prior to winter and will overwinter within the cells to later emerge as adults. The young adults will chew their way out of the cell the following spring. They will survive as solitary bees throughout their life, requiring no support from their relatives. They are quite docile and do not portray any form of aggression, unlike like other types of bees. In fact, a leafcutter bee sting is less painful when compared to its counterparts. They pose no serious danger to humans and will only sting when provoked.
Leafcutter bees pollinate many wildflowers and are generalists pollinators. They will pollinate most vegetables and fruits and can serve well in most commercial farms that require pollination services. Some of the crops and fruits pollinated by leafcutter bees include alfalfa, blueberries, carrots, and onions.
Just like honeybees and other types of bees, the leafcutter bee has its share of enemies. Beetles, parasitic wasps, and flies target leafcutter bees. Ants will also attack them.
Leafcutter Bee Cocoon Incubation
Once a leafcutter deposits an egg and provides the pollen loaf, the sealed larva will hibernate in its cells for a defined period of time. This is what is referred to as incubation. The duration of the leafcutter bee incubation is temperature dependent, with warmer conditions accelerating the incubation period.
Leafcutter bee cocoons can be purchased, with the incubation period already kicked off. This will ultimately mean that the adult leafcutter bees will emerge a short time after. Alternatively, leafcutter bee cocoons can be raised on your own in the comfort of your home. If that is the case, then it is recommended that proper timing is considered to ensure the adult bees emerge at the right time. This is ideally during summer weather and when flowers have started to bloom.
The ideal conditions for leafcutter bee incubation include:
- A dark and warm area, which could be a water heater room, a secured outdoor area, or an unconditioned garage.
- An ideal temperature level is required since the warmer the temperature the quicker the leafcutter larva will develop and emerge. At 70 degrees Fahrenheit, it will take 42 days for adult bees to emerge and at 84 degrees Fahrenheit; the adult bees will emerge after 20 days. It is also important to keep the temperature within the required level. If temperatures exceed 90 degrees F, the cocoons should be moved to a cooler location to avoid killing the bees.
- Well-insulated and aerated rooms should be provided for the cocoons. There should also be sufficient space for keeping the cocoons.
The life cycle of certain leafcutter bee species tends to be much shorter when compared to others. And hence there is a need to be on the lookout for the adults that emerge early. Any of them that begin to emerge earlier than others should be immediately placed in the bee house. Later on, when the other leafcutter bees begin to emerge, it will be wise to place the cocoons in a hatchery or your chosen container that is placed inside the bee house.
Leafcutter bee cocoons should be well-secured during incubation, especially when they have been placed in field shelters. Rodents and woodpeckers are the main culprits that will target these cocoons when placed outdoors. The ideal material to use to keep them off is a hardware cloth or any similar material that can secure the cocoons.
The leafcutter bee cocoons will never be adversely affected by short exposure to cold temperatures, even when below 15 degrees Fahrenheit. Unfortunately, extended cold periods or freezing conditions will have a slight impact and should therefore be avoided. Additionally, high temperatures tend to encourage the build-up of pests and parasites that destroy leafcutter bee cocoons.
The cocoons are best kept within controlled conditions. The arrangement of the nests should also be in the right direction, that is, with tunnel entrance should face up. That way, the emerging leafcutter bees can exit the cocoons using the right direction. Any attempt for these bees to exit the cocoons using the wrong direction will lead to injury and possible death of themselves and the bees that stand in their way.
In some instances, the leafcutter bee cocoons can be stored as loose cells within refrigerated conditions. Some of the commonly used storage include buckets, drums, and feed sacks. These should have holes that provide free air movement. Anything that is airtight such as plastic bags should never be used as storage material for the cocoons. These prove to be harmful to the developing larva.
With cold storage and incubation, it becomes easier to manage pests and parasites. It also becomes much easier to clean and disinfect the cocoons since the bees are dormant in this stage.
The male leafcutter bees are always the first to emerge, emerging 18 days from the incubation date. Two days later the female leafcutter bees will emerge. Bee emergence can always be delayed if the conditions are not right for release. This could mean there are cool wet conditions, a delay in bloom, or crops and fruit trees have just been sprayed. To delay the emergence, temperatures should be lowered to about 65 degrees Fahrenheit on the 14th day from the day of incubation.
Setting up a Leafcutter Bee House in Summer
Just like all other wild bees, leafcutter bees require some early morning sun to be active. The leafcutter bee house should therefore be well positioned. By this we mean, the house should be south or southeast facing. The house should also be properly sheltered during the afternoons, more so in areas with plenty of sun exposure.
The leafcutter bee house can be placed almost anywhere desirable. This includes trees, a fence, or on walls. The house should be properly secured to prevent the house from swinging or making some funny noises. Either of these is a complete turn-off to bees and they will abscond a house for that reason. Furthermore, leafcutter bee houses should be placed in close proximity to pollen and nectar sources. There should also be a source of clean water close by.
The elevation of a leafcutter bee house should be high enough and out of reach for its predators. Ideally, a 5 feet position off the ground is best, not only to keep away predators but also for easy monitoring of the bees. You should also provide preferred nesting holes to the leafcutter bees. The best size is of 6mm diameter at the opening. The nesting holes should be made of high-quality material and clean.
The outside of the bee house should be secured using a wire or hardware cloth with ¾ inch openings. Additionally, the holes should be properly aligned with open ends facing outwards and the tube pushed to the back of the nesting house.
Leafcutter bees should be well-secured from the elements, that is, rain, wind and direct sun. It is also important to keep the house safe from birds. For weather elements, a roof that is 2 to 3 inches longer than the nesting house will help provide shelter and direct rainwater away from the leafcutter bee house. It is also important to ensure the bee house does not smell of paint by the time the leafcutter bees are living in the house. This can be achieved by painting the house a month prior to bringing in the leafcutter bees.
As for the nesting holes, it is important to keep the diameter at 6mm. each solitary leafcutter bee will utilize one nesting hole, filling it up with several eggs before moving to the next hole where the process is repeated. At the end of its life, it will fill up one or two holes. These bees never damage furniture or any wooden item, but they establish their nests in already existing holes.
To keep the leafcutter bees healthy, nesting materials should be easy to open and clean. They should also be replaced once each year. The nesting hole should accommodate 2 leafcutter bee cocoons, comprising a male and a female.
Release the Leafcutter Bee Cocoons
When the time is right and prevailing conditions ideal, the leafcutter bee cocoons can then be released. To release the leafcutter bee cocoons simply means to place the cocoons inside a bee house where the bees will emerge and start their summer activities. These should be placed inside the bee house. Leafcutter bee cocoons should not necessarily be placed in the nesting holes since emerging bees will always find a nesting hole by themselves.
The cocoons should be released under below conditions:
- Consistent day temperatures of 75 degrees Fahrenheit at minimum.
- Flowering plants with blooms are available for the bees.
When releasing the leafcutter bee cocoons, these are placed inside the bee house and on top of the tubes. The cocoons should not be exposed to direct sunlight and should be kept within the required temperatures. If all conditions are right, the adult leafcutter bees should emerge within 1 to 10 days from the day of release. If not, then you can expect the bees to emerge after 3 weeks, especially if it is cold.
Since leafcutter bees are solitary insects, it means the female will raise her young on her own. They build their nests inside existing holes or nesting materials and will spend a better part of their lifetime within the nest. Young leafcutter bees have the tendency of coming back to lay eggs where they hatched when they are mature bees. It is therefore important to release the leafcutter bee cocoons close to the bee house or inside the bee house. By doing this, you increase the chance that these bees will come back and establish their cocoons in the bee house.
Let Cocoons Develop and Bees Emerge
Ideally for online purchases of leafcutter bee cocoons, it will take 1 to 10 days for the young leafcutter bees to finally emerge. Prior to this, the cocoons should be provided with the right conditions and allowed to develop and then finally emerge.
After the emergence of the leafcutter bees, the yard and garden should be ready to receive the summer bees.
The leafcutter bees require the following after emergence:
1. The nest or bee house
A well-constructed and solid bee house is required for raising the leafcutter bees. This can be mounted on a solid wall, fence, or post. The house should be properly secured against predators such as ants and birds. The house should also be well-sheltered from the elements. As mentioned earlier, keep the bee house at an elevated position of about 5 feet from the ground. It should also face south to southeast to allow the bees to catch an early sun.
2. Nesting material
Leafcutter bees preferred nesting diameter is 6mm and the material should be breathable with a thick wall. One end of the nesting material should be sealed and the other end left open to keep the bees safe from pathogens and parasites that include pollen mites, mold, parasitic wasps, and chalkbrood.
Leafcutter bees should be allowed to emerge when the prevailing temperature conditions are 70 degrees Fahrenheit or more during the day. The night temperatures do not matter a big deal for the leafcutter bees if they have a well-sheltered home at night.
4. Nesting materials
Emerging leafcutter bees have a preference when it comes to nesting materials. They are drawn to broadleaf deciduous plants with soft and flexible leaves and petals. The leaves will be used for constructing protective walls over their cocoons. It also helps when sealing the nests. Desired plants for leafcutter bees include redbud trees, alfalfa, hostas, buckwheat, lilac, peas, and other deciduous plants. These trees should be within 30 square feet of the nest to make it more accessible for the leafcutter bees.
Leafcutter bees rely on nectar and pollen for sustenance, with a single leafcutter bee visiting between 10,000 to 20,000 flowers in its lifetime. The pollen and nectar collected are used for feeding its offspring. The more the bloom, the more offspring the leafcutter bee can raise. It is therefore wise to plant as many native plants for the bees as possible. The absence of required flowers will force the leafcutter bees to move to some other location.
6. Avoid chemicals
Leafcutter bees are sensitive to chemicals and they should thus be raised within a chemical-free environment. First off, purchase seeds, plants, and bulbs that are not contaminated with chemicals since the chemicals will harm the bees. Secondly, if you have to use chemicals then opt for organic chemicals for pest control. These should however be applied at night and when there is no rain or wind. That way, the bees will not be impacted by the chemicals. The use of chemicals will impair the normal growth and production of the leafcutter bees. It impairs female bee memory making the bees forget their nest. It will also encourage the development of male offspring and increase predisposition to parasites and diseases.
Remove Nesting Materials in Fall and Winter
Winter and fall are the opportune seasons for leafcutter bee cocoons to hibernate. Your task as the keeper at this time is to keep them safe from predators and the only way to do this is by removal of nesting materials. These should then be placed in a fine mesh bag.
All nesting tubes should be kept in unheated storage during fall and winter, with their capped ends up. The cocoons can be harvested later during spring. By fall and winter, the female leafcutter bee should have produced as many cells as possible. These are filled and capped in a number of tunnels. This winter and fall management of leafcutter bees is primarily about keeping the larvae safe until their incubation period which will occur during spring.
The leafcutter bee offspring normally undergoes the egg and larval stages before spinning itself in a cocoon that will help it survive the low winter temperatures.
The leafcutter bee nests that are capped at 70 to 80% are usually removed and safeguarded from birds, weather, rodents, and other invaders. This is normally carried out during the day when the adult leafcutter bees are away from the nest. The empty spaces can be replaced with empty nests, but that will depend on the date and bee population. Ideally, there should be a proper number of nesting spaces available at any given time.
Once the native flower blooms have ceased, most of the leafcutter nests should be taken away from the field, with the least capped left behind for some time. As for those using polystyrene and Styrofoam nests, these should be removed immediately before the onset of cool wet seasons since they are prone to mold problems.
All nesting boxes that have been removed from the field should be stacked and stored under temperatures of 68 degrees Fahrenheit for a period of three weeks, or 82 degrees Fahrenheit for two weeks. Doing so will allow the eggs to hatch, the larva to feed and then spin its cocoon.
Parasites are a serious threat to leafcutter bees even during fall and will try to mate and invade the growing larva. The ultimate effect of this is a decreased live count and increased parasites during the next season’s incubation. Ideal control measures for parasites during fall include water traps and vacuuming. Insect zappers and black lights are also used as parasite control measures during fall.
Harvest and Store Cocoons in Spring
The practice of harvesting and storing leafcutter bee cocoons during spring is an important one since it helps raise a healthy bee population. Additionally, it makes it possible to find out the population count of the bees.
Parasites and diseases thrive best in a productive leafcutter bee environment and with the emerging bees living close to each other, it becomes easier for the pests and diseases to spread. It, therefore, goes without saying that harvesting the leafcutter bee cocoons will help keep a check on this. This is the only ideal way to keep off pests and parasites such as parasitic wasps and Chalkbrood.
Any artificial bee house should be kept clean at all times and that responsibility is bestowed upon the keeper. Taking time to harvest the leafcutter bee cocoons not only ensures the health of the current bees but also the future generation bees. Remember, leafcutter bees are able to give birth to their second generation of bees.
The ideal time for harvesting leafcutter bee cocoons is during early spring when native flowers begin to bloom. The cocoons should be given time to develop and later for the adult bees to emerge.
- Newspapers/old sheet.
- Breathable and transparent bag for incubation.
- Cocoon comb or screwdriver.
- An old toothbrush or stiff wire brush.
Once the cocoons are harvested, you will need to store them without washing, since these are not waterproof. The cocoons should be stored in a Beeguard bag or any transparent and breathable bag. You can transfer this to your garage where it will be kept until it is time for incubation.
Diseases and Pests that Affect Leafcutter Bees
Just like honeybees and other summer bees, leafcutter bees faced serious dangers from diseases and predators. They face similar enemies as mason bees even though there exist some clear differences.
A sure way to attain bee health in leafcutter bees is by continuously monitoring and maintaining the bee house. Proper management of the bee house and the leafcutter bees will help eliminate most of the pests, parasites and diseases that affect the bees. With proper harvesting, storage and cleaning, leafcutter bees can be guaranteed of enjoying good health. All these will help prevent disease and pest build-up and spread, consequently boosting the well-being of the bees.
The main parasites that attack leafcutter bees have been categorized into two as explained below:
Also referred to as kleptoparasites, these will steal food from the developing leafcutter larva and in some instances eat the larva. These mothers of the parasites will lay their eggs inside the leafcutter bee cocoon. This will gorge on the food deposits intended for the leafcutter larva and mature faster. Examples of these include the dried fruit moth, the Indian meal moth, carpet beetles, blister beetles, checkered flower beetles,
Body snatching parasites
These are the kinds that are injected into the cocoon wall by their parasitic mothers. The female utilizes its ovipositor in executing her malicious behaviour. Once the parasitic egg is hatched it kills and eats the maturing bee. Examples of these parasites include chalcid wasps, sapygid wasps, and cuckoo bees, chrysidid wasps.
Pest and Disease Control in Leafcutter Bees
The strategies for controlling pests and diseases in all bees tend to be similar since most of them share the same enemies. Some of these include:
- The nesting materials should be removed at the end of the season.
- During harvesting, be on the lookout for parasitic pest cocoons and separate these before destroying them. In most cases, the parasitic cocoons are easy to decipher.
- Be on the lookout for early emerging bee pests that target leafcutter bees. For instance, the cuckoo bees that have pointed abdomens and spines at the tip will emerge earlier.
- Harvesting of the leafcutter bee cocoons will help counter most of the common pests and diseases. One common disease such as the Chalkbrood can be controlled by harvesting the cocoons. Doing so will help keep the adult bees safe since they will not crawl through infected cells, also helping avoid the spread of the disease.
- Cleaning of nesting material before the onset of the next season. This, therefore, means any nesting materials that cannot be opened to facilitate cleaning should be avoided.
Purchasing Leafcutter Bees
You have a few reliable options for purchasing leafcutter bees online. The bees are sold in cocoons, unlike honeybees which are sold as live bees. You can check out the many different sites that sell leafcutter bee cocoons online. However, a reliable online supplier is the Crown Bees which can be accessed by clicking here. The convenience made possible with online makes it possible for you to place an order with the emergence dates at the back of your mind.
The ideal timing for leafcutter bee emergence is during summer when there is enough bloom for the bees. This period is also desirable given the prevailing temperatures. Leafcutter bee cocoons are temperature sensitive hence the need to plan well before making orders. One big advantage of this supplier is the fact that you can place your orders in advance and schedule deliveries to coincide with the summer month. You will also enjoy delivery to your doorstep, keeping the cocoons safe during transit without temperature fluctuations. You can also order the cocoons with the bee house.
The leafcutter bee is also called Megachile Latreille. It comes from a bee species that comprises over 1,500 members with 50 subgenera. Within this family include carder bees, mason bees, and resin bees. Leafcutter bees derive their name from their behavior that involves cutting off plant leaves that are used for building their nests. The female bee will use the leaves to build brood chambers where eggs will be laid, develop throughout winter, and later emerge as an adult leafcutter bee during spring. The leafcutter bees are solitary bees and that means they do not live collectively in a colony the way honeybees do. They also carry pollen on their underside, unlike honeybees that carry it on their legs.
These bees are also friendly to humans and will only sting when provoked, even so, their stinger is less harmful when compared to that of its counterpart the honeybee. Surprisingly, female leafcutter bees live for only 2 months and will lay about 35 to 40 eggs in their lifetime. These bees are excellent pollinators and beekeepers use them to provide commercial services to plantations and other smallholder farmers. They can pollinate most crops that include alfalfa, melons, carrots, peas, blueberries, onions, legumes, cranberries, and many others.