Along the Path

By Susan Rothrock Deo

The Bee’s Knees: The Elegance of California Bumblebees and other Native Bee Pollinators 

The other day I watched a fat little bumblebee climb around inside a poppy. She buzzed onto one, then another, the sacs on her hind legs filling with pollen. I marveled at the beauty of her black and yellow fuzzy body, the skill with which she navigated the bright orange flowers. Recently, scientists taught some bumblebees to roll a little ball into a hole for a reward–a drop of nectar. Bumblebees who had not been trained learned how to do it by merely watching the trained bees! 

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Worker bees and queens (all females) gather pollen for protein. They leave a scent marking the flower as one that has already been visited so other bumblebees don’t waste their time there. Each bumblebee carries about 25% of her weight in pollen back to the hive. Bumblebees and European honeybees are the only social bees. Other species are solitary. Bumblebee hives are in the ground and much smaller than honeybee hives. Bumblebees are native while honey bees were imported from Europe to help pollinate agricultural crops. Being “generalists” (not particular about what flowers they mine for nectar and pollen), honey bees also visit ornamental and native plants. Only honey bees make honey. Native bees store pollen for their larvae—in individual cells for each. 

Both male and female bees gather nectar for carbohydrates. Pollen sticks to the hairs on their bodies so both sexes can be effective pollinators. Pollinators are anything that helps transfer pollen from the male part of the flower to the female part of the same, or another, flower. Without this fertilization there would be no seed or fruit. In addition to bees, animal pollinators include hummingbirds, bats, and a variety of insects from butterflies to beetles. Over 80% of terrestrial plant species require an animal pollinator (mostly insects) to reproduce. Native bees and other pollinators are much more efficient than honey bees because they have evolved with native flowers: the shape of their bodies and mouth parts, the appeal of the flower’s color or scent, the time of day or night and time of year the species blooms. For example, bees like blue, purple, violet, white and yellow flowers and can see ultraviolet markings that we can’t. Bees can’t see red, however, and are not particularly attracted to tubular flowers, thus red flowers, especially tubular ones, are pollinated by hummingbirds. 

Worldwide there are about 20,000 species of bees, including over 250 species of bumblebees.  In North America there are 5,000 bee species, with 1,600 in California, including twenty-six species of bumblebees. Two of the bumblebee species found in Southern California are the yellow-faced bumblebee, Bombus vosnesenskii, and the California bumblebee, Bombus californicus. A number of native species are disappearing due to reduction of their habitats, loss of preferred flower species, excessive use of pesticides, and fierce competition from the honey bee. 

Native bees are fun to watch. They are not aggressive like honey bees and wasps. You can find them on your hikes or in your own yard by seeking out patches of native plants in bloom. To attract native bees, you need to provide food, shelter and water. Creating a native plant garden, even a small one, is the best way to provide food.  Some favorite plants of local bees are native sages and buckwheats, California goldenrod (Solidago californica), California lilac (Ceanothus spp), California poppy (Eschscholzia californica), and penstemon spp. The more native plants, the more native bees. If you cultivate the patience to wait for them to show up, they are “the bee’s knees” to watch!

Interesting fact: Bumblebees are an important pollinator of tomatoes, which they “buzz” pollinate. They do not transfer pollen with their bodies but rather the buzzing of their wings close to the flowers moves the air enough to shake the pollen loose!

Additional Resources

Common California Bee Groups from UC Berkeley Urban Bee Lab (including photos):

http://www.helpabee.org/common-bee-groups-of-ca.html

Best Bee Plants for California from UC Berkeley Urban Bee Lab:

http://www.helpabee.org/best-bee-plants-for-california.html

How you can help with bee conservation from the Xerxes Society for Invertebrate Conservation:

https://www.xerces.org/endangered-species/wild-bees

Nature’s Best Hope: A New Approach to Conservation that Starts in Your Yard by Douglas W. Tallamy (See review in this issue.)

Common Bee Groups in California

Apidae

This is a large group of bees that includes honeybees, cuckoo bees, digger bees, carpenter bees, orchid bees and bumblebees (which are discussed in the adjacent article). Carpenter bees use strong mouthparts to burrow into wood like dead tree stumps or boards. Inside they create branched tunnels to raise their young.

Colletidae

These are also called membrane bees or plaster bees because they line their holes with a cellophane-like secretion that is waterproof and resistant to fungus. Some are unable to carry pollen on their legs, so they use their crops, structures in their digestive tract that store and soften food.

Andrenidae

Mining bees are quite small and nest in the ground. They build branching tunnels and fill them with pollen, on which they lay their eggs. Their whole metamorphosis takes place inside these holes. They are among the first to emerge in the spring. Many of this group of bees are very specialized, getting their pollen from only a few species.

Halictidae

This is the second largest family of bees, also called sweat bees because some, especially the smaller ones, land on your skin and lick your sweat. Most nest in the ground, some in wood, and some lay their eggs on the food of another species. One interesting species, Agapastemon texanus, the green sweat bee, has a beautiful iridescent green exoskeleton.

Megachilidae

This large and diverse group of bees includes leaf-cutting, mason, resin or wool carder bees. They primarily nest in premade tubular cavities, like holes in wood, old plant stems, or even snail shells and make their larval chambers by using such objects as leaves, flowers, mud, resin, plant hairs or pebbles.

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