If you've ever seen honey bees foraging on primrose, you may have seen something unusual.
What's with the pollen hanging below their hind legs as they buzz from primrose to primrose?
There's a reason for that.
Distinguished emeritus professor Robbin Thorp of the UC Davis Department of Entomology and Nemalogy alerted us to the reason.
"Note the stringy mass (mess) of pollen hanging below the hind legs of the bee," Thorp points out. "Honey bees have great difficulty in collecting (actually packing into their corbiculae) pollen from any large flowered species of Oenothera. The pollen grains are very large, more than 100 microns, and tied together with viscin threads to form a webby mass. This is ideal for transfer by hawkmoths where stringy masses get attached to their undersides as they probe for nectar."
"Oenothera pollen," Thorp says, "can be collected by some native bees where the scopae are modified to contain sparse simple hairs where the webby pollen can be easily stored. But the corbiculae of honey bees are not well suited to handle this webby stuff, since it will not pass neatly through the 'pollen mill' of the honey bee hind leg."
He recalls seeing the same situation when honey bees were working his desert evening primroses.
And speaking of honey bees, it's National Honey Bee Day on Saturday, Aug. 22.
Extension apiculturist (emeritus) Eric Mussen of the UC Davis Department of Entomology and Nematology, wrote a piece on a UC ANR blog published this week. He initially published it in the June 2013 edition of the UC IPM Retail Nursery & Garden Center IPM News but it's quite timely.
"The actual cause of honey bee decline is still uncertain," Mussen says. "What is known is a number of factors are probably involved. Honey bees are their most robust and able to best contend with stresses when well fed. In addition to water, honey bees require nectar sources for carbohydrates and a varied mix of pollens to provide proteins, lipids, vitamins, minerals, sterols, antioxidants, and other nutrients. Drought, flooding, and conversion of former foraging grounds into large agricultural monocultures, highways, airports, developments, and so forth have led to honey bee malnutrition in many locations."
"In the last 20 years beekeepers have been encountering a series of previously exotic pests that invade the hive and kill bees, such as the varroa mite; new honey bee diseases, including Nosemaceranae; and many viruses."
"Pesticides can also be involved in bee decline, especially when applied to plants when they are in bloom and bees are foraging," Mussen points out. "Many insecticides are highly toxic to bees including virtually all organophosphates, carbamates, and pyrethroids. If not killed in the field, foraging bees can collect residue-contaminated pollens and bring them back to the hive for immediate consumption or long-term storage. There are serious concerns over the chronic, sublethal effects of these residues on the physiology of immature and adult bees."
"A newer class of insecticides, the neonicotinoids, which include imidacloprid, clothianidin, and dinotefuran, also pose hazards for honey bees. These products are systemic materials that move through the plant and are included in the nectar and pollen of flowers when they bloom. Although the neonicotinoid residues may not kill bees immediately, they may have sublethal effects, such as suppressing immune and detoxification systems, causing bees to be more sensitive to other stresses."
If you want to know more about neonics, be sure to attend the UC Davis neonics conference on "Truth or Myth: Neonicotinoids and Their Impact on Pollinators: What Is the Science-Based Research?” from 10 a.m. to 4 p.m., Wednesday, Sept. 9 in the UC Davis Conference Center. UC Davis researchers and state officials will address the crowd, announced conference coordinator Dave Fujino, director of the UC Davis-based California Center for Urban Horticulture. You can register on the CCUH website.
Honey bees sometimes get into little battles with one another.
Here's a case of a tiff over a Tithonia.
Two honey bees wanted the same Mexican sunflower (Tithonia). They each tried to claim the same blossom, bounced one another off, returned, and then battled again.
This particular blossom seemed especially inviting to them, while all around them were other Tithonias.
Sisters from the same hive? Competitors?
It's difficult to say. But at the end, there was only one winner.
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An educational opportunity to learn more about them--the truths and the myths--will take place on Wednesday, Sept. 9 at the University of Caifornia, Davis, and you're invited. It's open to the public.
The conference, themed “Truth or Myth: Neonicotinoids and Their Impact on Pollinators: What Is the Science-Based Research?” will take place from 10 a.m. to 4 p.m. in the UC Davis Conference Center, 550 Alumni Lane.
UC Davis researchers and state officials will address the crowd, announced conference coordinator Dave Fujino, director of the UC Davis-based California Center for Urban Horticulture.
“We are pleased to have such a knowledgeable lineup of UC Davis researchers who will clarify the issue of impact of neonicotinoid impacts on pollinators by summarizing and presenting the past and current science-based research,” Fujino said. “We are also fortunate to have additional presentations on the regulation guidelines on neonicotinoids and their role in controlling invasive pests in California, and a diverse group of stakeholders participating in a panel discussion on the neonicotinoid issue.”
Neonicotinoids, recently implicated in the worldwide die-off of pollinators, including honey bees, are a class of neuro-active insecticides chemically similar to nicotine. Considered important in the control of many significant agricultural and veterinary pests, they target the central nervous system of insects, resulting in paralysis and death. “Neonics,” as they're called, are commonly used on farms, and around homes, schools, and city landscapes.
Michael Parrella, professor and chair of the UC Davis Department of Entomology, will provide an overview of the current use of neonicotinoids and the role of honey bees in California agriculture. Six other speakers are scheduled, along with a panel discussion.
The speakers include:
- Brian Leahy, director of the California Department of Pesticide Regulation, who will discuss “California Pesticide Regulation of Neonicotinoids”
- Nick Condos, director of the Plant Health and Pest Prevention Services Division, California Department of Food and Agriculture, “Neonicotinoid Risks Associated with Invasive Species Management”
- Karen Jetter, associate project economist, UC Agricultural Issues Center, “Trends in Neonicotinoid Usage in California Agriculture and the Control of Invasive Species”
- Margaret “Rei” Scampavia, a doctoral candidate who studies with major professors Neal Williams and Ed Lewis of the UC Davis Department of Entomology and Nematology, “Past Neonicotinoid and Bee Research”
- Elina Lastro Niño, Extension apiculturist based at the Harry H. Laidlaw Honey Bee Research Facility, UC Davis, “Current Neonicotinoid and Bee Research.”
The California Center for Urban Horticulture (CCUH) will co-host the event with the UC Davis Department of Entomology and Nematology and the UC Agriculture and Natural Resources.
Sponsors include California Association of Nurseries and Garden Centers (CANGC), a trade organization founded in 1911 to promote and protect the California nursery industry; Four Winds Growers, based in Winters, Calif.; Scotts Miracle-Gro, a company headquartered in Marysville, Ohio, and known as the world's largest marketer of branded consumer lawn and garden products; and Monrovia, a horticultural craftsmen company headquartered in Azusa, Calif.
At the close of the conference, Fujino will preside over a panel discussion on neonicotinoid issues and concerns. Questions and answers from the audience will follow. The panel is to include a UC Cooperative Extension farm advisor, and representatives from the California Association of Nurseries and Garden Centers, Home Depot, Scotts Miracle-Gro, Bayer CropScience and the American Beekeeping Federation.
The registration fee of $50 will include lunch, as well as the post-conference social hour. To register, access the CCHU website at http://ccuh.ucdavis.edu/public/copy_of_public/neonicotinoid-pollinator-conference-2015/neonic or contact CCUH representative Kate Lincoln at email@example.com or (530) 752-6642.
The European Union recently adopted a proposal to restrict the use of three pesticides belonging to the neonicotinoid family (clothianidin, imidacloprid and thiametoxam) for a period of two years. In addition, the U.S. Fish and Wildlife Service announced that by January 2016, it will ban the use of seeds treated with neonicotinoid pesticides and the use of crops improved through biotechnology throughout the 150 million acres managed by the National Wildlife Refuge System.
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Beekeepers don't like their "girls" foraging in California buckeye (Aesculus californica)
It's poisonous to bees.
"The signs of poisoning can be as severe as dying adult bees and brood, only dying brood, brood that barely makes it and emerges misshapen, brood that emerges undersized, and probably bees that don't live normal lifespans, but we haven't proven that," says Extension apiculturist emeritus Eric Mussen, who, although retired, continues to maintain an office in Briggs Hall, UC Davis campus.
Is it the pollen or the nectar that's poisonous?
Possibly it's only the pollen that contains the toxin, "but some pollen always ends up in the nectar and honey," Mussen says.
"It is all a matter of dilution. When many different plants are producing pollen and nectar at the same time as the buckeye, sometimes the bees escape undamaged. However, beekeepers have long known that on dry years the buckeye is the best producer of both pollen and nectar, so the bees go for it.
What to do? Bees can fly some five miles from the hive to collect nectar and pollen. It isn't always possible for beekeepers to move their bees out of areas with buckeye, "especially on dry years--we've had more than enough of those," Mussen says.
"Otherwise, they feed the bees with substitute, pollen traps might help a bit but most beekeepers don't have them, they feed sugar syrup, and if they can do it, they take the buckeye-pollen combs out. If the combs are left in, the buckeye pollen gets stored. It gets covered up when fresh pollens start coming in, and things seem to straighten out."
"Then long comes another pollen and nectar dearth and the bees dig into the stores. It is not uncommon to have the bees 'buckeyed' twice in one year," Mussen says.
"California buckeye was discovered in the early 1800s in California and described by Edouard Spach in 1834 (Little 1979, Hickman 1993)," writes Frank Callahan of Central Point, Ore. writing for the Native Plant Society of Oregon.
"All parts of California buckeye are toxic to humans and livestock," Callahan points out. "Poisoning is from glycosidal compounds that are present in all plant parts. Humans have been poisoned by honey made from the flowers (USDA Forest Service 1974). The flowers are toxic to European honeybees (Apis mellifera); however, native pollinators relish the collection of nectar without side effects. The adult pale swallowtail butterfly (Papilio eurymedon) appears particularly fond of this plant."
Yes, we've seen butterflies nectaring on the buckeye. Never seen a buckeye butterfly (Junonia coenia) nectaring on a California buckeye, though!
Two species of male sunflower bees, Svastra obliqua and Melissodes agilis, spend the day on our Mexican sunflowers (Tithonia) chasing the girls and protecting their turf.
Sometimes I wonder why they don't tire out sooner than they do. The Energizer Bunny could take lessons from them.
But a night, it's a different story.
While the female sunflower bees return to their underground nests at night, the males sleep in a tight cluster on the nearby lavender stems. These boys are s-o-o tired that they're often "in bed" by 5 or 6 p.m.
But their cousins, the honey bees, are still foraging, gathering pollen and nectar for their colony.
So what a surprise last weekend to see a worker bee doing what her name implies--working!--on a lavender blossom next to the sleeping boy bees, Melissodes agilis. "Excuse me, boys! There's nectar here! Do ya mind? Could you move over just a little bit?"
I aimed my little pocket camera, a Nikon P340, and caught the girl on the boys' night out.
She'll be back. So will the boys.
(Editor's Note: You can learn more about native bees in the Heyday book, California Bees and Blooms, a Guide for Gardeners and Naturalists, written by UC-affiliated authors Gordon Frankie, Robbin Thorp, Rollin E. Coville, and Barbara Ertter.)