There's exciting news today out of the Department of Entomology and Nematology, University of Califoirnia, Davis.
A team of researchers--two faculty members and a graduate student--just published a paper on bee immunity and toxin metabolism today (Nov. 9) in Scientific Reports, part of the Nature Publishing Group. The team: assistant professor Rachel Vannettte; and assistant professor Brian Johnson and his graduate student, Abbas Mohamed.
The journal article is titled Forager Bees (Apis mellifera) Highly Express Immune and Detoxification Genes in Tissues Associated with Nectar Processing.
When honey bees shift from nurse bees to foragers, or from caring for the brood to foraging for nectar and pollen, the bees “turn on” gene expression with products that protect against microorganisms and degrade toxins, they discovered,
“First, the results suggest that forager bees may use antimicrobial peptides—short sequences of amino acids with general activity-- to reduce microbial growth in stored food resources,” said Vannette, who joined the faculty in September as assistant professor after a postdoctoral fellowship at Stanford University. “This would be a largely unrecognized way that bees protect honey and potentially other stored resources from microbial spoilage. Second, this work shows that forager bees produce toxin-degrading enzymes in nectar-processing tissues.”
“This may allow forager bees to degrade many different kinds of compounds in nectar, before it is stored,” Vannette said. “Bees also vary in their ability to do this—foragers have a greater ability to degrade a variety of compounds than nurses. This may have implications for hive health and management.”
The scientists found the change in nectar-processing tissues, but not in the gut. The scientists surmised that the exposure to bacteria or yeasts in the environment may trigger this change, but they did not examine it in the study. it in the study.
"Nice paper,” said Gene Robinson, director of the Institute for Genomic Biology and Swanlund Chair of Entomology, University of Illinois at Urbana-Champaign, who was not involved in the research. “It had been well known that the division of labor in a honey bee colony is supported by extensive differences in brain gene expression between bees that perform different jobs. This new research shows nicely that this genomic differentiation extends beyond the brain; different complements of active genes in a variety of tissues make each bee better suited for the job it needs to perform."
The team plans to follow up with functional assays to examine the potential of these gene products to (1) reduce microbial growth and (2) degrade a variety of natural and synthetic compounds.
So, we're anxiously awaiting to hear more!
The wild bee research co-authored by 58 bee scientists and published today (June 16) in Nature Communications is drawing a lot of attention--and well it should.
Pointing out that wild bee diversity is declining worldwide at unprecedented rates, the researchers said steps must be taken to conserve them--and not just those that are the main pollinators of agricultural crops.
"This study provides important support for the role of wild bees to crop pollination through a comprehensive global summary,” said co-author and pollination ecologist Neal Williams, associate professor in the UC Davis Department of Entomology and Nematology. “At the same time, we found that in any one region, much of the pollination services from wild bees to a given crop come from just a few species, thus we need to be careful about using a simplistic economic ecosystem-services argument for biodiversity conservation and maintain actions that target biodiversity as specific goal. "
The study, led by David Kleijn of Wageningen University, The Netherlands, found that of the almost 80 percent of crop pollination provided solely by wild bees, only 2 percent are by the most common species. This indicates that the benefits of conserving only economically important organisms are not the same as the benefits of conserving a broad diversity of species, the researchers said.
The paper, “Delivery of Crop Pollination Services is an Insufficient Argument for Wild Pollinator Conservation,” is online at http://www.nature.com/naturecommunications. Among the co-authors are native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology at UC Davis, and conservation biologist Claire Kremen of UC Berkeley, a longtime associate of the UC Davis Department of Entomology and Nematology.
Wrote the researchers in their abstract: “There is compelling evidence that more diverse ecosystems deliver greater benefits to people, and these ecosystem services have become a key argument for biodiversity conservation. However, it is unclear how much biodiversity is needed to deliver ecosystem services in a cost-effective way. Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops.”
“Dominant crop pollinators,” they pointed out, “persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just ecosystem-service-based arguments.”
The researchers analyzed data from more than 90 studies on five continents, including Europe and North America. They concluded that the higher levels of biodiversity provide greater benefits to the functioning and stability of ecosystems, with some functions also being “economically beneficial” for humans.
Kleijn and his colleagues studied 785 species, analyzing which provide the best economic returns from crop pollination. They found that wild bee communities contribute an average of more than $3,251 per hectare (2.471 acres) to the production of crops, and that they provide the same economic contributions as managed honey bee colonies. However, they also noted that the majority of crop pollination services provided by wild bees are accomplished by only a small subset of the most common species.
“Across the 90 studies, we collected a total of 73,649 individual bees of 785 species visiting crop flowers,” the authors wrote. “Although is an impressive number, it represents only 12.6 percent of the currently known number of species occurring in the states or countries where our studies took place. When we consider only bee species that contribute 5 percent or more to the relative visitation rate of any single study, the percentage drops to 3 percent of the species in the regional species pool. Yet these 2 percent of species account for almost 80 percent of all crop visits.”
These results suggest that conservation efforts targeted directly at a few species providing the majority of ecosystem services, such as crop pollination, would represent a good strategy if the goal is to improve economic returns. However, they said such a strategy is unlikely to be compatible with conserving threatened species and biological diversity “if the goal is to improve the functioning and stability of ecosystems.”
Williams worked with Kleijn and Winfree of Rutgers University New Brunswick, N.J., to conceive of some of the approaches used, particularly suggested looking at the abundance distributions of crop bees within the larger species pools of the region to understand whether the most important crop pollinators species are simply the common bees overall. Williams and Kremen also contributed to the manuscript, from the early drafts to the final versions.
As an aside, we certainly hope that this global research packs a social media wallop and leads to efforts to protect and preserve our wild bees. Unfortunately, many people never think about wild bees. It's "out of sight, out of mind," not "absence makes the heart grow fonder."
We'd all do well to take a look at the amazing macro bee images by Sam Droege, head 'of the bee inventory and monitoring program at the U.S. Geological Survey (USGS). His work has been featured in publications all over the world. Among the latest: National Geographic. See his USGS work posted on Flickr. And check out his book, An Up-Close Look at Pollinators Around the World, co-authored by Laurence Packer.
Absence CAN make the heart grow fonder...
Newly published research by a Michigan State University-led team indicates that one of the reasons why the varroa mite is so destructive is because it infiltrates hives by smelling like a bee.
The parasitic mite, or Varroa destructor, is a "blood sucker" that feeds on bees. Scientists and beekeepers alike consider it the world's No. 1 enemy of honey bees.
MSU entomologist Zachary Huang, a lead author of the paper in Biology Letters, and his fellow researchers showed that "mites are able to change their surface chemicals to an entirely different species of honeybees," according to an article in the American Bee Journal. "Further, they also revealed that the mites were able to make these changes rather quickly - adapting in days rather than evolving over generations."
The varroa mite was initially found in Asian honey bees (Apis cerana) and then shifted hosts to the European honey bee (Apis mellifera). It was first detected in the United States in 1987. Today it is found in hives throughout the world except in Australia.
The eight-legged reddish-brown parasite, about 1–1.8 mm long and 1.5–2 mm wide, is a blood sucker that's difficult to control, according to Extension apiculturist emeritus Eric Mussen of the UC Davis Department of Entomology and Nematology. Mites transmit viruses (there are now some 22 named RNA viruses) that can wipe out a hive. A familiar mite-transmitted disease that beekeepers see is DWV or Deformed Wing Virus. Mites can also lower the protein level of a bee's blood, and reduce its weight and life span.
Mussen says that mites spread from colony to colony by phoresy (animal-to-animal transport). They ride on flying drones (males) and adult worker bees (females). They also spread changing hosts on flowers.
"A mite enters a honey bee cell just before or during the time it is being capped," Mussen points out. "It feeds on older larva or prepupa. Sixty hours later, the mite lays its first egg. The egg will hatch in about 24 hours."
"The number and release of offspring depend on the length of the pupal stage. The queen is pupa for 8.5 days (no mites). The worker is pupa for 12.5 days (1.3 mites) and the drone is pupa for 14.7 days (3 or 4 mites)," he says. Thus, due to the longer time required for drone development, drone pupae get the worst of it.
"When maturing, the newly emerged mites climb onto adult bees and feed by puncturing the intersegmental membranes and sucking the bee blood," Mussen related recently to a UC Davis class. "Often these are nurse bees that stay around the brood nest. Sometimes the hosts are drones and older foragers that are flying from the hive every day. Eventually the new mite climbs off the nurse bee onto a comb in the brood nest and enters a cell. The reproductive cycle starts and within 6 days, 44 percent of the young mites have moved into the brood cells; within 12 days, 69 percent of the mites are in the brood cells; and within 24 days, 90 percent of the mite are in the brood cells."
"If there is no brood, the mite has to feed on adult bee blood every six days or so to remain alive," Mussen says. "Mite life expectancy in summer is around 60 days; bees about 42 days. Mite life expectancy in the winter is up to 9 months; bees about six months."
Now if scientists could only figure out how to eliminate the varroa mite from the world's hives...
Debra Jamison, state regent of the California State Society of the Daughters of the American Revolution. loves bees. So when it came time to select a fundraising project, she knew what she wanted to do.
Jamison adopted the motto, “Bees are at the heart of our existence” and vowed to support honey bee research and enhance honey bee environments to help the beleaguered bees.
Jamison, whose first name means “bee” in Hebrew, says she's had a lifelong “love and respect for bees.” Her project? She chose to help bee research at the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road at the University of California, Davis, and support the adjacent Häagen-Dazs Honey Bee Haven, owned and maintained by the UC Davis Department of Entomology and Nematology.
Last year Jamison and her fellow members of the California State Society donated $30,000 to bee scientist Brian Johnson. Then this year they gifted $15,000 to the garden, which was planted in 2009 as a year-around food resource for the Laidlaw bees and other pollinators. It also serves to create public awareness for the plight of bees, and as an educational garden, where visitors can glean ideas for their own gardens.
The check was presented at a “lunch-with-the-bees” celebration organized by the UC Davis College of Agricultural and Environmental Sciences. Some 125 DAR members, some from as far away as Chico and San Diego, dined beneath a canopy of olive trees bordering the road.
“We appreciate this more than we can say,” said Ed Lewis, professor and vice chair of the department--and whose mother belongs to DAR.
On behalf of the department, haven manager Christine Casey accepted the check from Jamison and Karen Montgomery of Modesto, the state regent's project chair. The department used some of the funds to purchase two benches. Other projects will include a shade structure in the Growers Grove section and more bee habitat.
Honey bees prefaced the American Revolutionary War (1765-1783) by 143 years. European colonists brought the honey bee to Jamestown colony, Virginia, in 1622. Descendants of the American Revolutionary War formed DAR in 1890.
“Our 114 chapters and 15 districts have worked diligently to educate members, children, and the public about the plight of bees,” Jamison said. “This outreach has been truly outstanding. Add to that the phenomenal fundraising efforts. I truly thought that when I brought this project before the members that they might think, ‘Eeeeeuuuu, creepy insect, and weird state regent.'
Jamison singled out several DAR members for special recognition. She praised Karen Montgomery, state chair of the project and member of the Major Hugh Moss Chapter, Modesto, and committee members Susan Montgomery of the Major Hugh Moss Chapter; and Diane Groome, Carol Vercellino and Sharon Paukkert, all of the José Maria Amador Chapter, Pleasanton. “Thank you all, from the bottom of my heart, for all of your work to raise funds for this project,” Jamison said
Jamison presented certificates of appreciation to Extension apiculturist Eric Mussen and communication specialist Kathy Keatley Garvey of the UC Davis Department of Entomology and Nematology for their work in helping DAR with the two-year project.
"Bee Patriotic” rally towels decorated each table. Last year Jamison's rally towels were lettered with “Bee-lieve in the Power of DAR." All those attending the March 28th luncheon received a “I Bee-long to DAR” recyclable grocery bag.
The crowd toured the haven and ended the day with hearing bee presentations in the Laidlaw facility conference room.
Mussen talked about the life cycle of bees and the issues bees face: malnutrition, pesticides, pests, parasites, diseases and stress. Malnutrition, Mussen said, is a bigger problem now than colony collapse disorder (CCD), a mysterious malady characterized by adult bees abandoning the hive. An active colony of honey bees requires an acre-equivalent of mixed blooms, daily, to meet their nutritional needs.
Mussen urged the DAR members to plant for bees, especially plants that normally bloom in late summer and fall, or delay plantings so that they result in late summer/fall blossoms. Good plant lists, he said, can be found on the UC Davis Entomology and Nematology's bee biology website (see Honey Bees), and on the Xerces website, under “Pollinator Conservation Resource Center.”
Mussen also warned that simply because certain pesticides are labeled for use in organic gardening does not mean that they are less dangerous for non-target insects, particularly pollinators. Also, insecticides that are watered into the soil and move from the roots, systemically throughout the plants, are secreted in the nectar and pollens when the treated plants bloom.
“We are just studying certain mixes of fungicides, insect growth regulators, and newer adjuvants that can cause serious damage to honey bee brood, even though that information is not on the labels,” Mussen said.
In thanking the DAR members Johnson said the $30,000 will cover a two-year period of graduate student research. His graduate student, Gerard Smith, researches the effect of pesticide exposure in the field on honey bee foraging behavior, and graduate student Cameron Jasper studies the genetic basis of division of labor in honey bees.
The haven is open from dawn to dusk every day. Admission is free. To commemorate National Public Gardens Day, a special event (free) will take place from 5:30 to 7 p.m. on Friday, May 9. It will include a guide tour at 6 p.m. and a give-away of sunflower seeds (while they last).
It's a topic we've all been waiting for: "Honey Bee Health and Disease Resistance."
Jay Evans, a research entomologist with the USDA's Agricultural Research Service (USDA-ARS) Beltsville Bee Research Laboratory for the past 14 years, will discuss "Bee Disease Resistance and Colony Health" on Wednesday, Oct. 2 to open the fall seminar series hosted by the UC Davis Department of Entomology and Nematology.
His lecture, open to all interested persons, is from 12:10 to 1 p.m. in Room 122 of Briggs Hall, located on Kleiber Hall Drive, UC Davis campus.
"Honey bees are vulnerable to poor nutrition, parasites and pathogens, and exposure to chemicals," Evans said. "These threats can occur in batches and little is known about the impacts of multiple challenges to honey bee health, and about the abilities of bees to fend off these threats. I will present recent work aimed at determining the impacts of multiple parasites on bee health. I will also discuss the impacts Varroa mites, chemicals, and bacterial symbionts on bee health and colony losses."
As a research entomologist, Evans has focused his projects on a range of bee pests including bacteria, fungi, viruses and, mites, and beetles. He is especially interested in the immune defenses of bees toward these threats.
Evans was an early proponent of the Honey Bee Genome Project and helped recruit and organize scientists interested in applied genomics for bees. He has improved and applied genetic screens for possible causes of colony collapse disorder and is now heading a consortium to sequence the genome of the Varroa mite in order to develop novel control methods for this key pest.
Evans holds a bachelor's degree in biology from Princeton and a doctorate in biology from the University of Utah.
The fall seminars, coordinated by faculty members Joanna Chiu and Brian Johnson, will be held every Wednesday noon through Dec. 11 in 122 Briggs Hall, except for Nov. 27, Thanksgiving Week, when no seminar will be held.
Under the coordination of professor James R. Carey, all seminars are to be videotaped and posted at a later date on UCTV.
Anyone with a computer can view the seminars, and yes, they're free.