- Author: Kathy Keatley Garvey
They're there for the pollen.
"California poppies provide only pollen--no nectar," native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, told the Pollinator Gardening Workshop last Saturday on the UC Davis campus. Thorp was one of the featured speakers at the event, sponsored by the California Center for Urban Horticulture.
Thorp, who identifies thousands of bees a year for researchers, enthralled the audience with facts about bees. Although he retired in 1994, he maintains an office at the Harry H. Laidlaw Jr. Honey Bee Research Facility at UC Davis, and is one of the instructors of The Bee Course.
Some of the information he presented:
- Unlike wasps, which are carnivorous, "bees are vegans." They gather pollen and nectar from plants. (They also collect water and propolis, or plant resin, for their colonies.)
- "Flowers don't have wings; so we need the pollinators to come to them."
- The global population of bees includes some 19,500 named species. Of that number, about 4000 different species of bees occur in North America; 1600 in California, and more than 300 species of bees in Yolo County. (Over the last four years, Thorp has found more than 80 species of bees in the Häagen-Dazs Honey Bee Haven a half-acre bee friendly garden on Bee Biology Road maintained by the UC Davis Department of Entomology and Nematology.)
- Seventy percent of bees are solitary, and most nest in the soil.
- Fifteen percent of bees are cuckoo bees; the females lay their eggs in other bees' nest and their offspring eat the provisions
- Only 10 percent of bees are social (honey bees are among them)
Thorp recommends that if you want to attract native bees, provide food (bee plants), water and shelter. "Leave some bare soil, avoid mulch madness, and provide bee condos (drilled blocks of wood that blue orchard bees and leafcutting bees use for their nesting sites.)
"Plant it and they will come," Thorp said. "Provide habitat and they will stay and reproduce."
Thorp is the co-author of a newly published book, "Bumble Bees of North America" (Princeton University Press) and a co-author (with Gordon Frankie of UC Berkeley and colleagues) of a pending book with the working title, "California Bees and Blooms."
One of the websites Thorp recommends is the UC Berkeley Urban Bee Lab website, http://www.helpabee.org/, which provides information on native bees, gardening for bees, and current projects and partnerships.
- Author: Kathy Keatley Garvey
St. Patrick's Day is the "wearing of the green," but it's also the "wearing of the yellow."
Wild mustard, that is.
If you drive through the hills of Napa, around St. Patrick's Day, or from January through March, you'll see bee hives nestled in the green landscape with a flourish of mustard (Brassica spp.).
It's a child's delight, a photographer's dream, and a painter's inspiration. But mustard is also a good cover crop and bee food.
Indeed, honey bees crave mustard just like folks on "Irish Day" crave corned bee and cabbage (with that yellow condiment made from mustard seeds).
- Author: Kathy Keatley Garvey
The European honey bee, also known as the Western honey bee, has been in the United States for s-o-o-o long that we think it's a native.
It's not. European colonists brought the honey bee (Apis mellifera) to the Jamestown colony (Virginia) in 1622. The native Americans called it "the white man's fly." And the honey bee wasn't even introduced to California until 1853. That was in the middle of the California Gold Rush, 1848-1858, when it arrived in the San Jose area.
Our ancestors quickly became quite fond of the industrious little pollinator and honey/wax producer buzzing around them.
Today, as they did, we frequently see non-native and native bees sharing nectar resources, such as in the photos below of honey bees and yellow-faced bumble bees (Bombus vosnesenskii).
We're often asked: "Do honey bees, being an invasive species, impact the native bees?"
We put that question to Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology. He's served as California's Extension apiculturist since 1976, almost 40 years.
His answer: "We do not have a definitive answer to that question. But, since honey bees have been living in what is now the U.S. for just short of 400 years, it is likely that honey bees and native bees determined, long ago, how to partition resources at any particular location so that both species survived. It is true that only honey bees can be moved into and out of a specific location overnight, and that might put a stress on local populations of native bees, but I never have heard of honey bees eliminating native bees from any particular spot."
That's the buzz on bees.
- Author: Kathy Keatley Garvey
Along about this time of year, the calls come pouring into the UC Davis Department of Entomology and Nematology and the Bohart Museum of Entomology.
- "I just saw a golden bumble bee. I think it's a new species! Can I name it?"
- "I just saw a huge bee and it's gold in color and all fluffy with green eyes!"
- "I just saw a huge bumble bee flying around in our backyard. It's yellow and I think it's a pest."
Not!
It's the male Valley carpenter bee, Xylocopa varipuncta, which native pollinator specialist Robbin Thorp, emeritus professor of entomology at the Department of Entomology and Nematology at the University of California, Davis, calls "the teddy bear" bee.
Like all male bees, it doesn't sting.
But what's unusual about this bee is its color, golden with green eyes. It's sexual dimorphism at its best, because the female Valley carpenter bees are solid black.
The Valley carpenter bee is the biggest carpenter bee in California. And it scares the living beejeez (dead beejeez, too) out of young children, teenagers, and adults. Just about everybody and everything, including the family dog and cat.
As Thorp told us several years ago for a news story:
"Xylocopa varipuncta occurs in the Central Valley and southern California, Arizona, New Mexico and southward through Mexico. It is large (about the size of a queen bumble bee), with all black females and golden/buff-colored males with green eyes. Females have dark wings with violet reflections."
Some folks think it's a pest. It's not. It's a pollinator. Let it "bee."
- Author: Kathy Keatley Garvey
Monarchs and milkweed are in the news again.
As well they should be.
The declining monarch population, coupled with the decreasing scarcity of their host plant, the milkweed, is disturbing. The larvae of the monarch butterfly (Danaus plexippus) feed exclusively on milkweeds. No milkweed, no monarchs.
Butterfly expert Art Shapiro, distinguished professor of evolution and ecology at UC Davis, says the problem hasn't totally reached California yet. "The 'dearth of milkweed' problem is primarily an East/Midwest problem, due to increased use of Roundup since the introduction of 'Roundup-ready' GM crops. It's quite real. There is no such problem out here--at least yet--but there is a new milkweed pathogen that may cause one! Dave Rizzo (UC Davis Department of Plant Pathology) and I hope to publish on it shortly. No harm in planting milkweeds, but the problem isn't a California one, at least not yet."
Journalist-photographer Alessandra Bergamin, writing in the Feb. 18 edition of Bay Nature: Exploring Nature in the San Francisco Bay Area, says that "the number of monarchs overwintering in Mexico's Oyamel fir forest has reached an all-time low," quoting the World Wildlife Fund in Mexico. "The reports suggest that factors such as loss of habitat, climate change and use of insecticides have contributed to the decline."
The situation in California, however, looked better than bleak last year. A little better. "Monarch butterfly populations in California's coastal overwintering sites showed a slight — and surprising — rebound in 2013 after more than a decade of dwindling numbers," Bergamin wrote. "The 2013 Western Monarch Thanksgiving Count tallied 211,275 monarchs at 162 sites from Sonoma County to San Diego County, up from 144,812 the year before."
Over the past two decades, however, the Western monarch population has dramatically declined in California, she pointed out in her article, "Western Monarch Population Hanging On." The downward trend is expected to continue.
Meanwhile, the Xerces Society for Invertebrate Conservation, headquartered in Portland, Ore., has posted a seed finder resource so folks can find milkweed seed in their state and plant the seeds in their gardens, parks, landscapes, restoration areas and on farms.
Oakland parks supervisor Tora Rocha is taking it one step further. She is collecting the monarch caterpillars, rearing them, and releasing the adults in the Lakeside Gardens at Lake Merritt. Her newly formed Pollinator Posse has sparked the interest of volunteers, who range from school children to city council members. They all want to save the monarchs.
Rocha bans pesticides and herbicides from her pollinator gardens. “For the past fifteen years the gardens have had a pesticide-and herbicide-free policy,” Rocha told writer Constance Taylor of Wild Oakland, which offers free, Oakland-centered environmental education. “We also rely on volunteers contributing thousands of hours to keep our parks maintained--about 75% of the work is done by volunteers.”
Rocha says it's not enough to be a custodian of the land: it's important to be a steward of the land and protect the pollinators. She's created a video, posted on YouTube, that explains what she and the other Pollinator Posse members do.
Rocha and colleague Eddie Dunbar of the Insect Sciences Museum of California and a fellow Pollinator Posse member, recently visited UC Davis to share information with Shapiro and native pollinator specialist Robbin Thorp, emeritus professor of entomology.
Another person keen on butterflies is Sally Levinson of Berkeley, who writes a blog on butterflies and is publishing educational videos, including "Secret Lives of Monarchs" and "In the Company of Wild Butterflies." As a graduate student at UC Riverside, Levinson studied with major professor Bruce Hammock, now a distinguished professor of entomology at UC Davis. (He maintains a joint appointment with the Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.)
As an aside, the Bohart Museum of Entomology at UC Davis offers a "Got Milkweed?" t-shirt spotlighting the monarch and its host plant. The work of doctoral candidate Fran Keller and Bohart volunteer/naturalist Greg Kareofelas, the t-shirt is available online or at the museum, located in Room 1122 of the Academic Surge building on Crocker Lane.
Want monarchs? Plant milkweed.
