As concern grows over the decline in the honey bee population, alternative pollinators are gaining attention. Mason bees, which are native to North America, are one option. These gentle-natured bees do not produce honey but they excel at pollinating and are easy to raise.
The mason bee is a solitary bee which lives in natural cavities such as woodpecker holes or hollow stems. They also seem to be just as happy in artificially-constructed nests, so long as these nests include tubes made of cardboard or paper where the female bee can lay her eggs.
Purpose-built nests, often called bee boxes, are set out in early spring when daytime temperatures regularly reach 55 degrees. The bee box is placed outside, facing south in a location that is sunny but protected from wind and rain. Because mason bees will not fly farther than three hundred yards from their nest, bee boxes must be located within range of fruit trees and flowering plants.
The mason bee gathers pollen on her underside. As she zig-zags among the blossoms she is picking up and dropping off pollen, thus pollinating the flowers as she travels. One mason bee can pollinate 2,000 blossoms in a single day. She brings pollen back to her nest and deposits it at the back of the tube, making a mound on which she will lay one egg. She then seals the space off with mud to create a cell. It is because they use mud in their nest construction that they are called mason bees.
All this activity can be closely watched since the bees don't sting. The female can be seen heading into her chamber when she is laden with pollen, and backing into her chamber when she is about to lay an egg. Sometimes she just likes to rest in the front of the chamber. This activity continues for six to eight weeks, and then the mother bee dies.
Mason bee larvae hatch a few days after their eggs are laid. The larvae eat the pollen the mother has provided and then each larva goes into a pupal stage. The following spring, the adult bees emerge. The males emerge from the nest first, the females follow, and the process begins all over again.
More information on mason bees can be found at the Crown Bees website.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
It's important to protect our bee populations because their survival and reproduction provides pollination benefits for agricultural, urban, and wildland environments. This is especially evident here when we welcome commercial bees to pollinate almond orchards each spring. These almond blossoms are only the beginning of the rich agricultural smorgasbord relying on pollination from bees. Our bubble of bee knowledge is largely limited to social bees that live in colonies and are used commercially in orchards, fields, and green houses. The most well-known in the American landscape, the honeybee (Apis mellifera L.), was first introduced by European settlers along the Eastern seaboard in the early 17th century. Documentary evidence tells us it took over 200 years for the European honeybee to make its way to California.
While there are over 4,000 species of bees found in North America, California is home to 1,600 native species. These natives were here prior to the arrival of European honeybees. European honeybees may have been introduced to California in 1853 from swarms purchased in Panama, carried across the Isthmus, and shipped to San Francisco. Apparently only one swarm made the arduous trip and was delivered to F. G. Appleton, a San Jose apiarist. Until this time, diverse native bee communities were the primary pollinators, filling a wide range of ecological roles throughout our state.
Native bees are actually better adapted to meet the needs of a broad diversity of flowering plants in urban, suburban, and rural areas. While one third of our food crops rely on both native bees and commercial honeybees for pollination, home gardens mostly rely on healthy native bee populations. It's been estimated that only 25 to 40 percent of native flowering plant species are pollinated by honeybees. In order to protect ecosystem resilience and diversity, we need to protect the health of our native bees.
Most native bees are not aggressive and are not inclined to sting since unlike honeybees they are not protecting their hive. Males generally have no sting. Females may sting if swatted or stepped on, but they don't have enough venom for the sting to be painful. Native bees range in size from tiny to large and vary in color.
Some of the natives seen in my Paradise garden include the following:
- Carpenter bees (Xylocopa varipuncta) are social, forming a small colony that nests in wood. The female Valley carpenter bee is about an inch long black bee that resembles a bumble bee but is less hairy. The male, commonly known as "the teddy bear bee," is green-eyed and blond. Small carpenter bees (Ceratina) also tunnel into wood, are nearly hairless, and are metallic-looking. Some species sport yellow markings and can be mistaken for flies.
- Sweat bees (Halictidae)are attracted to salty sweat. This species of bee is metallic green, blue, or black with greenish-yellow markings.
- Bumble bees (Bombus). Feral honeybees and bumble bees constitute a large percentage of the bees I see daily. Like honeybees, bumble bees are social and live in small colonies, unlike the solitary native bees.
Native bees are unsung heroes. Some, such as the yellow-faced bumble bee (Bombus vosnesenskii) are better pollinators than honeybees because of their foraging behaviors and large, hairy bodies. Agricultural crop systems, as well as urban and wildland environments, benefit from native bees. The reproduction and survival of diverse species of native bees depend on all of us. Dr. Gordon Frankie, professor and research entomologist at University of California, Berkeley, recommends the following to protect our native bee populations:
- Eliminate pesticides
- Plant a diversity of nectar and pollen rich plants (ten or more species)
- Mass each plant in patches of ten square feet
- Choose plants that bloom in succession over the growing season
- Avoid excessive pruning and manicuring of ornamental flowers
- Set aside bare patches of soil for nesting
Not only will these behaviors help protect our bee populations, but they will also attract other pollinators.
Many factors contribute to declining native bee numbers: increased use of chemicals; loss of wildflower meadows and other suitable habitats; more land being developed for commercial and residential property, landscapes incorporating more hardscape and fewer pollen-producing plants. Plus, homeowners are quick to call pest control companies to eradicate unwanted bugs rather than try to implement Integrated Pest Management (IPM) methods. The solution to turning around the declining health of native bees is to act individually and proactively, as well as to raise awareness. Here are some steps we can take:
- Support local nurseries that sell plants and seeds that haven't been treated with neonicotinoids, a class of pesticides commonly used as seed treatments (NSTs) and systemic sprays in greenhouses.
- Buy organic vegetable seeds or packs.
- Ask if in doubt about a particular plant you're interested in purchasing. The same applies to food. Supporting local farmers markets helps promote sustainable agriculture, and may help keep harmful pesticides out of the soil and water. Many of the venders at farmers markets do not use neonicotinoids when growing their fruits, flowers, and vegetables. And they are right there at the market to talk about their farming practices.
Learning to manage your pests through IPM tactics will also help minimize adverse effects on declining bee populations. The University of California's IPM website provides scientific, location-specific pest control information for homeowners. Homes become less toxic to pets and children when their play areas are not treated with pesticides. Homeowners can share what's working in their gardens with neighbors and friends, which may help eliminate pesticides in other yards and gardens.
Providing food, shelter, and nesting areas for wildlife in the garden will also help our native bees. Pollen is protein for bees and nectar is their carbohydrate, providing energy and maintaining water balance in their diet. Plant a variety of annuals and perennials in the garden for bees to enjoy. Provide water sources. A shallow dish filled with pebbles and water will not only provide bees with a drinking station but will help other beneficial insects as well.
It is vital that our bee populations are protected. Their survival and reproduction provide pollination benefits that sustain our planet. While native bees go unnoticed, learning more about them and protecting their natural habitats will help assist these prolific pollinators and insure our own well-being.
To learn more about bees, investigate the following sources:
- The Xerces Society
- The UCANR publication, Native Bees are a Rich Resource in Urban California Gardens
- The Pollinator Partnership
- The UC Berkeley Urban Bee Lab
- Real Dirt article by Cindy Weiner, “Bumble Bees in the Garden
Information in this article has been derived from:
- California Native Plant Society, Small Wonders: The Plight and Promise of California's Native Bees by Emily Underwood, June 24, 2021Ecosphere, volume 11 issue 2 February 2020
- Ecosphere, volume 11 issue 2 February 2020, Dara A. Stanley, Simangele M. Msweli, Steven D. Johnson, Native honeybees as flower visitors and pollinators in wild plant communities in a biodiversity hotspot
- Kellar, Brenda, Honey Bees Across America
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu (preferred) or call (530) 538-7201.
One of the amusements a garden can provide is watching the birds, bees, butterflies and other critters drawn to it. Most of us have seen honeybees flying from flower to flower, sipping nectar or collecting pollen to take back to their colony. Honeybees, however, are not native to the western hemisphere. They originated in Eurasia and Africa and were imported to North America by immigrants in the 17th century. Before that time, pollination services for both wild and cultivated plants were provided by a host of native bees. There are about 4000 different species of bees native to the United States, and 1600 of those species are found in California. Most of these bees are solitary with each female making her own nest; most often the nests are in the ground, but some bee species nest above ground.
Bumble bees are one group of native bees. The body of a bumble bee generally has lots of black hair with contrasting bands of yellow, red, or white. Different species have different color patterns. Bumble bees are as large as or larger than honeybees. Female honeybee and bumble bee workers both have pollen baskets on their hind legs, which they use to carry the pollen they collect. A pollen basket is a shallow depression in the leg surrounded by a fringe of long hairs. Workers and males are similar in size, but queens are much larger. Both queens and workers have stingers, but they are not aggressive and rarely sting. Males don't have stingers.
When the workers become adults, they take over foraging for nectar and pollen. The queen remains in the nest to lay more eggs as the colony grows and develops.
In late summer,some of the fertilized eggs are fed more frequently and longer than usual. These develop into new queens. The queen also lays some unfertilized eggs that will develop into male bees. Once they leave the colony, the males forage to feed themselves but don't return to the nest. They spend their days eating and searching for new queens to fertilize. At night they sleep in trees or shrubbery. In the fall the old queen, workers and males all die. Each new queen hibernates separately in a cavity in the ground until it is time for her to emerge the following year to begin her own colony.
As a bumble bee moves around inside the flower, pollen collects on her hair; she uses her legs to transfer the pollen to the pollen basket. Some flowers have pollen that is contained within tubular anthers that open only at one end or through a narrow slit on the side. These anthers must be vibrated or shaken to release the pollen through the opening. Plants that function in this way include some common garden vegetables like tomatoes, eggplants, potatoes and peppers, as well as native plants like shooting stars and manzanita. Bumble bees (along with a few other bee species, but not honeybees) have evolved a specialized method called buzz pollination to obtain pollen from these plants. Bumble bees grasp the tubular anthers while vibrating their flight muscles without moving their wings. The vibration shakes the pollen loose, and it falls onto the bumble bee. Having bumble bees in your garden can increase the yield of these crops.
Some insects superficially resemble bumblebees, but if you look closely, you can tell the difference. Carpenter bees have bodies that are mostly black and shiny with far less hair than bumble bees. The Valley Carpenter Bee is enormous, about one inch long, much larger than a bumble bee. The females are shiny black, and the males are fuzzy golden yellow with green eyes. Syrphid flies have abdomens that are striped black and yellow, but flies have only two wings and antennae that are short and stubby. Clearwing sphinx moths are yellow and black but larger than bumble bees. They hover in front of a flower, rather than landing on it, and their antennae are long and feathery.
Upcoming opportunity to learn more about bumble bees: John Whittlesey, owner of Canyon Creek Nursery and Design, will be presenting “Living with Bumble Bees” online on Wednesday, April 7 at 7pm during the general meeting of the Mount Lassen Chapter of the California Native Plant Society. This meeting is free and open to the public. Go to the chapter website and click on the program title to access the link to the Zoom meeting.
The Master Gardeners Spring Workshop Series has begun. Topics include: Diagnosing Plant Problems; Mason Bees; and Native Gardens. Others will be added soon. Visit our workshop webpage to read about these upcoming free workshops and to register (required).
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu (preferred) or call (530) 538-7201.
By Tom Hansen and Jeanne Lawrence, Butte County Master Gardeners, January 4, 2013
Just because it is wintertime doesn’t mean that bees, which are important pollinators for our flowers, fruits and vegetables, don’t need food. Plants and shrubs can provide pollen, nectar, or both to bees in our late winter and early spring.
Honey bees will be brought to Northern California from all across the US to begin pollinating the almond crop by mid-February. Although almonds don’t have a lot of nectar, they do have a lot of pollen, which allows the bees to build up the strength of their colonies after the arduous journey of travelling across the country.
Honey bees can forage as far away as three to five miles from their colony when conditions are favorable for flight, although most foragers tend to stay within a few hundred yards of the colony if it is near adequate food rewards (nectar and pollen). Honey bees will venture out from their hives when temperatures reach the mid-50s Fahrenheit; they won’t travel far, but they will search for sources of pollen and nectar nearby.
Because honey bee queens are constantly laying eggs and raising their young, these bees need food year-round. Honey bees forage when temperatures are 55 degrees and higher; they do not forage in rain or in wind stronger than 12 miles per hour. Cloudiness also reduces flight activity, especially near threshold temperatures. A honey bee normally flies at a speed of 18 miles per hour empty and 15 miles per hour carrying of load of pollen or nectar. However, if they are agitated and empty, honey bees can fly about 20 miles per hour. They cannot carry a load upwind against much more than a 15 mile-per-hour wind.
Native bees, like bumble bees and mason bees, are solitary and do not live together in hives like honeybees do. Solitary native bees were here long before the arrival of honey bees, which were introduced from Europe in the early 17th century. Native bees lay their eggs throughout the summer and fall and their pupae (young) develop in seclusion during the colder months. They need daytime temperatures of 65 to 70 degrees before they emerge as adults, so they will not begin pollinating until early April, or when daytime temperatures rise. While native bees do not play a significant role in almond pollination, they are critical in pollinating many of our summer fruits, vegetables and flowers.
Different species of pollinators are attracted to different types of flowers (generally those that suit their tongue length), but nearly all types of bees show interest in blue, yellow and ultraviolet hues.
Some guidelines for bee-friendly garden plantings include the following:
- Natural species (rather than hybrids) produce nectar and pollen that is more accessible for bees
- Native flowers can attract solitary bees (like mason bees)
- Grow a variety of species from different plant families
- Try to have something flowering throughout the season
- Plant several of one type of plant together – they will provide a better magnet for the bees
You can help bees out by planting mustards or clover as a cover crop – yellow mustard is one of the earliest blooming flowers that are attractive to honey bees. Native plants and shrubs that are attractive to bees include the California wildflower “Baby Blue Eyes,” and California Desert Bluebells, both of which are annuals; and California Dutchman’s Pipe, an attractive deciduous vine festooned with cream-colored flowers that have red-purple veins.
Non-native plants that are bee-friendly in our area include flowering quince, which is often the first noticeable flowering shrub of the year; the popular evergreen camellia japonica, some varieties of which bloom as early as November; and witch hazel (hamamelis), a yellow-flowering shrub with a distinctive fragrance and intriguing blossoms.
Crocus and hyacinth bulbs are also attractive to bees. These should be planted in November or December after spending 10 weeks chilling in a refrigerator ahead of time (as our climate is too mild to provide them the requisite chill hours) – and, like tulips, these are best treated as annuals in our climate.
When doing your winter garden clean-up, keep the bees in mind: leave some “wild,” messy areas in your yard for bees. For example, old fence posts, dead logs, and decaying sunflower heads all provide native bees with places to hide, nest, and raise their next generation.
Keep other pollinators in mind, too: for instance, instead of using a hummingbird feeder which you might only sporadically keep filled, provide natural nectar at this time of year by planting camellias, flowering quince and flowering currant.
Photo: Honeybee on prune blossom
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