Our Bees

Bumblebees (Bombus) are our only native pollinators that live in colonies. These colonies are short lived and only survive for one season.  It has one queen bee, and the rest are worker bees who take care of developing babies, gather food, and defend the nest.  The queens will mate before they hibernate, then emerge in the Spring and build the nest.  

Bumblebees prefer to create their nests in preexisting cavities such as rodent burrows, rock piles, and under layers of dense vegetation. The new queen will fill the nest with wax pots she has created by using wax flakes that she has collected from glands on her abdomen. In these pots she will fill with regurgitated nectar that is very similar to honey (minus one enzyme that is provided by honey bees alone).  After her pots are made and filled, she will make pollen balls and lay her first set of fertilized eggs (between 5-16 eggs) into the pollen balls. She will make sure the buckets of nectar she has created are close enough to her eggs because, like a bird, she will sit on her first batch of eggs to keep them warm until they hatch, and she needs a food supply close by so she doesn’t have to leave the nest. After they hatch, she will continue to sit on the larvae to keep them warm but will venture out for short periods of time to collect more food. After going through many larval stages, the larvae will go through a metamorphosis by spinning a silk cocoon around themselves and transforming into female worker bees.  

This first set of worker bees will immediately take over the duties of the queen bee so that she can focus on laying the hundreds of eggs that will be needed to maintain the hive. By mid-summer, the queen bee will switch over to laying unfertilized eggs that will be the males, and the specially fertilized eggs to create the next queens for the following Spring.  

After the male's hatch, they will leave the hive, never to return (though some species have been known to help with incubation for a short time before leaving the nest). They will either find their mates amongst the flowers or they will find a different hive and wait right outside of it and wait for their mates. The average lifespan of the male bumblebee is only two weeks as their main objective is to fertilize the emerging queens. They will only eat and mate, and then they will die before winter sets in. 

After the new queens hatch, they will leave the nest to look for mates (drones), and they will eat as much as possible in an effort to build up their fat reserves in preparation for winter.  As the weather cools, the drones, workers, and original queen will die, and the new queens will go into a type of hibernation. She will find a worthy location for overwintering and bury herself in loose soil under organic matter.  When the temperature warms up again, the queen comes out from underground and looks for a suitable place to start her colony.

Our bumblebees are some of our most efficient pollinators.   They mainly forage for pollen rather than nectar and transfer more pollen to the pistils with each visit. One of the things that make the bumblebees so great at pollinating is their fuzzy hairs. These fuzzy hairs (called Pile) are shown to be sensitive to the gentle electric signals that flowers send out. The electric field causes the hairs to be drawn to the flowers, similar to how our hair is drawn to a balloon after we rub it on our own hair. Their hairs also become electrically charged when they fly so when they crawl into the flower, the loose pollen will jump towards the bee making it easier for them to collect it. In addition to being electrically charged, the hairs are also branched and feathered so that when they do collect the pollen, it is more likely to stick to them.

Another way their hair helps them to be great pollinators is by helping to keep them warm. A bumblebee’s hair acts as insulation and as a result are able to work in temperatures below 50 degrees Fahrenheit and in rainy and/or windy weather.  They are able to be out pollinating earlier in the Spring and later in the Fall than all other bees.

Another interesting fact about the way that bumblebees pollinate is how they carry the pollen back to their nest. Most bees have a dense patch of long branched hairs on their abdomen or on their legs called scopa. These branched hairs grab onto and hold pollen for the bees. The bumblebees on the other hand have something called a pollen basket or corbicula, located on their hind legs.  The pollen basket is an indentation in the bee's leg that is surrounded by long hairs that hold the moistened pollen into place.  A bumblebee is able to easily carry around a million grains of pollen back to their nest because of these baskets. When these baskets are full, they are easily visible by you and I and can be seen as yellow balls on the bee’s leg.

Buzz Pollination

In addition to their long hairs helping them to be efficient pollinators, they (along with some other bees) also have a technique that makes them crucial for pollination- Buzz Pollination or Sonification. There are some tubular shaped flowers such as tomatoes, strawberries, blueberries, melons, and squash, that hold onto their pollen which can only exit out of small holds at the tip of the tubes. The bees do not have long enough tongues to reach the pollen and so they use a high frequency vibration to shake the pollen loose. The bees relax their wings and disconnect them from their muscles. They then vibrate their wing muscles, as if they are quickly flying, in order to get their whole bodies to vibrate.

• There are over 250 species of bumble bees in the world with 16 of those species found in the Pacific Northwest. 
• The most common species in the PNW are the Black-tailed bumble bee (bombus melanopygus), fuzzy-horned bumble (Bombus mixtus), Yellow-faced Bumblebee (Bombus vasnesenskii), and the California bumblebee (Bombus californica) 
• The Western Bumblebee (Bombus occidentalis) used to be the most common species in the west but this now rare species can only be found in remote mountain areas. One major factor in their decline is the introduction of pathogens by imported bumblebees used in greenhouse agriculture. If you see one of these rare bees, please immediately report the sighting to iNaturalist. 
• Bumblebees can remember our faces with repeated interactions 
• A queen bumblebee needs the nectar and pollen from about 6000 flowers per day in order to feed herself and her first set of babies 
• The worker bees will guard the nest by stinging anything posing a threat, and because their stinger is not barbed (like the honey bee) they are able to sting over and over again. 
• Bumblebee sizes vary between species and even within each species. Queen bees tend to be larger than the males or worker bees.

Food 

To best support our bumblebee's need for pollen and nectar for the longest period of time, please be sure to always have something blooming. Having a large variety of flowers blooming from Spring to late Fall will provide our bumblebees with the nutrition they need. Bumblebees are generalists and are not too picky about where they get their nectar and pollen from (though they do have favorites).  

One excellent pollen source that I see bumble bees in all the time is the California Poppy (Eschscholzia californica). California Poppies are easy to grow, spread easily, pop up from early spring to late in the fall, and they provide a good source of pollen that our bumbles love. Of course, California Poppies only provide pollen so you will also need flowers that provide the nectar that they need. Fortunately, the flowers that you grow for the nectar will also supply pollen and will be a nice one stop shop for our bumbles. But because bumblebees have different tongue lengths, favorite nectar sources vary. For example, the Nevada Bumblebee has a long tongue and prefers milkvetch, balsamroot, ceanothus, and sunflowers; the Fuzzy-horned Bumblebee has a medium-length tongue and prefers plants such as lupines, clovers, snowberry, blackberries, and raspberries. Your best bet will always be to grow a variety of native flowers. 

Habitat 

Providing habitat for bumblebees is just as important as providing pollen and nectar sources. Because our future queen bees overwinter under yard debris and in loose soil, please leave the leaves. The leaves and other natural yard debris provide an extra layer of insulation for the queens while they hibernate.  If you must rake your lawn, please do not shred the leaves but rather rake them into a corner of your yard and leave them there. If you can wait to rake, it would be even better if you waited until April or May, which is after the queen bees have woken up from hibernation. As a side note, allowing our native habitat to exist as it always had before we decided to tidy up nature, we allow all kinds of insects who have evolved to depend on leaf litter and yard debris, a chance to survive the winter. 

For nesting sites, bumblebees are opportunists. Many species prefer to nest underground but some species will nest in cavities they found from natural to manmade. Because most bumble bees nest underground, and favor holes made by rodents, if you have an area that has holes from rodents, and can be left untouched, please leave it for the bees. Avoid digging and tilling from early Spring until late summer which is when the bees will be building their nests. If leaving untouched soil is an unrealistic option, consider other forms of habitat support. You can create rock piles and grow bunch grasses such as Roemers Blue Fescue and Tufted Hairgrass.  You can also make or buy a Chickadee house which seems to be a bumble bee favorite. Just place dried moss in a house build specifically for Chickadees, and follow instructions on correct placement. After the Chickadees build their nest, the bumblebee may follow.  

Because there is much more to learn about bumble bee nest sites in North America, if you find a nest site, please go to Bumble Bee Watch , click on Record a Sighting, then click on Nest Sighting. You will first have to sign up with the program to submit your findings. 

Mason bees (Osmia) spend the majority of their lives inside of their nests. While in their nests, they spend their time eating, growing, spinning cocoons, and growing into adults. Even as adults, they remain in their nests until they rise from hibernation in the Spring.  

Mason bees nest in cavities such as hollow stems of plants and holes in wood created by wood-boring insects. They will search multiple cavities until a hole or tunnel that is just the right depth and width for child rearing is found. Once the ideal location is selected, the mason bee will then start collecting materials for building the nest. One of their favorite materials for building the walls in the nest is clay-rich mud, which is how the mason bee got it’s name. Mud is so important that the females will not build their nests if they do not have an adequate mud source close by. Once the female finds the perfect nest close to a perfect mud source, they will start to carry back balls of mud to this nest. The Mason bee will use this mud to create walls and columns inside the cavity, in order to give each new bee their own space. It usually requires 10 trips with these mud balls to create each wall.  

After she builds the first wall, she will start to collect pollen and nectar in order to make a pollen loaf for her babies. It takes about 25 trips for one pollen loaf.  She makes one pollen loaf and places one egg on top. After the loaf is made and the egg is laid, she will build another wall to separate her next baby and loaf.  In ideal conditions, the Mason bee can lay up to 30 eggs in their 6 weeks of life outside of the nest. The Mason bee has control over the sex of the eggs she lays. Fertilized eggs (haploid) will become the females and the unfertilized eggs (diploid) will become the males. The females are laid around 3 inches away from the entrance of the nest and the males will be laid in the first 3 inches. This is why it is important that the nest is around 6 inches deep. Shorter nests result in more male bees than females, which of course results in fewer Mason bees next year. 

A few days after the egg is laid, a larvae will emerge and begin to eat away at the pollen loaf. About 10 days later, it will spin a cocoon around itself and goes through a metamorphosis. By Fall, it will be a fully formed adult Mason bee. It will remain in it’s cocoon throughout winter in a form of winter dormancy. In the Spring, when the weather warms, the Mason bee will emerge from it’s cocoon. 

Once the bees are ready to leave their nests, they will chew and claw their way out. The males emerge 2-4 days before the females. They will sip on nectar and sit outside of other nests waiting for the females to emerge. They will then mate then die immediately after. After the females are done mating, they will start to look for a new nest.  

Mason bees have been called the perfect pollinators for Spring gardens and early blooming orchards. Because they can handle lower light levels and temperatures of 55°F, they are one of the first bees to arise from their nests. They pollinate for only a little over one month of the year but when they do they have a 95% pollination rate. There rates of pollination are 120 times greater than that of the honey bee, which has a pollination rate of only 5%. In fact, the USDA estimates that 300 mason bees in an apple orchard can perform the same pollination as 90,000 honey bees. Because Mason bees do not have a hive, they do not need to carry pollen back from the flowers. Instead, the pollen loosely sticks to their hairy bodies, where it will remain until it falls off when they land on the next flower.  

In addition to being early risers and effective pollinators, Mason bees are generalists and will pollinate all of the early blooming flowers including: Apricots, almonds, apples, blueberries, cherries, nectarines, peaches, plums, prunes, raspberries, strawberries, and even flowers with low sugar nectar, such as pears. They are so effective at pollination, that they are commonly sold commercially to orchards needing large amounts of pollination at the same time. Our native Western Blue Orchard Bee (Osmia lignaria propingua) is a popular one that can be purchased online. In fact, California, who has 80% of the world's almond populations, is struggling so much to supply the almond trees with enough honey bees, that they have begun to bring in Mason bees.  Paramount Farming Company, in Lost Hills, California, has been experimaneting with blue orchard bees for 8 years now. They have used the bees in conjunction with honeybees on 80 acres. He is seeing positive results in the almond orchards when the two pollinate together though they are still in the research phase. They use several hundred orchard bees to replace around 30,000 honey bees. 

Fortunately for the average home owner and gardener because we already have this bee naturally in our area, all we need to do to pollinate our Spring gardens and fruit trees is to provide them with a proper habitat. 

Food 

It is estimated that there are around 75 different species of mason bees (Osmia) in the Pacific Northwest. Because mason bees arise from their nests when the temperatures hit 55°F, they are usually ready to start foraging around March, and until the last Mason bee is done in mid-June. Because they start so early, they will need early blooming flowers such as Common Camas (Camassia quamash), Currant (Ribes spp.), Serviceberry (Amelanchier spp.), Ninebark (Physocarpus spp.), Maple (Acer spp.), Oregon Grape (Mahonia spp.), Salmonberry (Rubus spectabilis), Indian Plum (Oemleria cerasiformis), Wild Cherry (Prunus spp.), and Elderberry (Sambucus spp.). 

Shelter 

First of all, mason bees need proper nesting sites. They will often find their own nests in broken, hollow stems, and holes made by wood boring insects, but they can also be provided by you. You can either drill holes into untreated wood blocks or place hollow tubes into some kind of framed housing. Both need to be at least 6 inches deep, should range in width from 1/4” and 3/8”, and closed off in at the back.  The widths should vary due to the fact that we have many different species of mason bees that are also many different sizes. Please keep in mind that these nesting sites do need to be discarded or cleaned every year so something easily replaceable is ideal. The housing will need to be placed in a very sunny, Southeast facing position, protected from wind and shade. It needs to be between 5 and 7 feet off the ground and protected from rain (under an awning is perfect). 

A preferable and more natural approach to creating nesting for our mason bees, is to grow the plants that they naturally use for nesting such as elderberry (Sambucus spp.), sneezeweed (Helenium spp.), Thimbleberry (Rubus nutkanus), and Pacific Blackberry (Rubus ursinus). In the early Spring, cut back the plants from anywhere between 8” and 24” tall. They will use the stems at almost any angle including straight up and down, vertical, and horizontal. You could technically cut the stems and bundle them into a bee motel, but the risk of parasite invasions and predator attacks increases with larger numbers of bees nesting by each other. 

Second, mason bees need mud or soil with high amounts of clay. If you have clay soil, be sure to leave at least one area available and make sure it remains damp in the early spring. If you don’t have clay soil, you can buy some and put it in a basin. Put it close to your mason bee nests if you have one. 

 Leafcutter bees (Megachile) get their name from their distinctive nesting style. The female leafcutter will cut neat circular shapes along the outside of broadleaf leaves, petals, and other vegetation.  They use these cut leaves to line their nests in pre-existing cavities such as plant stems, insect tunnels in rotting wood, and even empty snail shells. Once a female finds a cavity that is long and wide enough, she will line it with leaves and petals to create a brood chamber. In this nest, are usually between 6 to 10 cells separated by a wall of chewed up leaves and resin. Each of these cells contain a single egg laid on top of a loaf made of pollen and nectar, which the larva will eat upon hatching.  She will position the males to the front of the nest because they hatch and develop faster than the females. Females are placed in the back of the nest since they take longer to develop. After hatching, the leafcutter larvae will overwinter in the nests then chew their way out come springtime. After they emerge, the male will only live for about one week outside of the nest. Their main objective is to mate with and fertilize the females. Once the females emerge, they immediately begin to build their nests and collect food for their babies. The females will only live outside of the nest for 5 to 8 weeks and will lay around 35 to 40 eggs within their lifetime.  

To support your leafcutter bee, be sure to grow some of their favorite plants for leaf cutting including: Roses, ash, redbud, lilac, aster, chokecherry, sunflowers, gaillardia, and Oregon Grape. The damage they cause to these plants is usually only aesthetic and rarely actually harms the plant. When cutting leaves, the leafcutter has very clean cuts whereas other insects (e.g. a Caterpillar) cuts will be more jagged.

Growing plants with hollow stems will provide a natural nesting site that they can easily identify. This includes joe-pye weed, elderberry, mountain mint, hydrangea, raspberries, and swamp milkweed.   
At the end of the growing season (December through March), cut the stems back to between 6-18 inches tall. By cutting back the stems, you have created homes for next year's bees.

Their interesting nesting habits are how the leafcutter bee got its name but there is another thing that makes them different than most other bees and that is how they carry their pollen. Where many bees carry pollen on their hind legs, the leafcutter bee will carry pollen on electromagnetic hairs (scopa) on the underside of their abdomen. Whereas honeybees and bumble bees wet the pollen for it to attach to their hind legs, the pollen sticks to their abdomen dry and therefore it spreads more easily making them a more efficient pollinator.  In fact, one of these bees can pollinate as many flowers as 20 honeybees.  

• They are solitary bees but will nest in close proximity to other leafcutter bees 
• Because they don't have a nest to defend, they are gentle. They only sting when handled and the sting is considered mild. 
• Their heads are larger than other bees because they have large mandibles that are used for cutting out of their nests and cutting leaves. 
• There are approximately 1100 species of leafcutters in the world and about 40 species found in the PNW
• Our most common leafcutter is the Western Leafcutter (Megachile perihirta), and the Silver-tailed Petal-cutter Bee (Megachile montivaga).