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November 19, 2015 - ABJ Extra
Camelina Cover Crops a Boon for Bees
By Jan Suszkiw
November 19, 2015
Camelina is an herbaceous, yellow-flowering member of the mustard family whose oil-rich seed and cold tolerance has piqued the interest of U.S. Department of Agriculture (USDA) scientists for its potential as both a winter cover crop and biodiesel resource.
Now, in the process of studying this plant, scientists with USDA's Agricultural Research Service (ARS) have found that its flowering period can provide honey bees and other insects with a critical, early-spring source of nectar and pollen that's usually unavailable then. This is especially true in Minnesota, South Dakota and North Dakota, where about one-third of the nation's managed bee colonies are kept from May through October.
The researchers observed that fields of winter camelina and winter canola (another alternate oilseed crop) produced about 100 pounds per acre of nectar sugar over the course of a two- to three-week flowering season. That quantity, produced in such a short time, is enough to support the annual energy requirements of a typical bee hive, which is 100-200 pounds of sugar per year, according to Frank Forcella, an agronomist with ARS' Soil Management Research Unit in Morris, Minnesota. He participated on a team of ARS and university scientists which evaluated the attractiveness of camelina, canola and a third oilseed crop—pennycress—during two years of outdoor field trials.
Highlights of the team's findings—reported in the June 2015 issue of Industrial Crops and Products—are:
• Insect counts showed that, besides honey bees, the three oilseeds also attracted wild bee species, butterflies, beetles, and hoverflies, whose larval stage feeds voraciously on aphids.
• Insects visited flowering canola up to 15 times more often than pennycress and camelina, perhaps because of higher nectar levels in each individual flower, which are much larger than those of camelina and pennycress.
• Canola failed to bloom during one of the study years, a reflection of it being less cold-hardy than the other two oilseeds.
• Camelina earned the highest marks overall, thanks to its optimal combination of desirable agronomic traits.
Read more about this research in the November issue of AgResearch. ARS is USDA's chief intramural scientific research agency
November 18, 2015 - ABJ Extra
North Carolina Student Investigates
Honey Bee Disease Alert Chemical Signal
Kaira Wagoner, University of North Carolina at Greensboro Biology Department’s first doctoral student, has uncovered a chemical that could increase the odds of honey bee survival by helping them better combat the parasites within their hives.
Wagoner has been working in Prof. Olav Rueppell’s lab under his mentorship since August 2011, when she began working on her Ph.D. in the newly established environmental health science program. She received bachelor’s degrees in biology and health science from Guilford College, and earned her master’s degree in biology from UNCG in 2011.
After studying the effects of malaria-carrying mosquitos in her master’s program, Wagoner said she wanted to study a “beneficial” insect for a change. She added that the “complex behaviors” of social insects such as honey bees added to their intrigue.
Wagoner’s research focuses on Varroa destructor, also called the Varroa mite.
The mite is “probably the single most problematic” issue for honey bees, she said. Not only is the mite a “physical burden to the honey bee,” it can also transmit viruses to the honey bee.
Varroa mites reproduce by infiltrating the special cells in a honey bee comb built for larvae. The mites lay their own young in the cell to feed off the baby honey bee. When that happens, the honey bee larvae give off a chemical signal that alerts the nurse honey bees to the presence of the mites and the disease that comes with it.
In response, the nurse bees uncap the wax covering from the cell to check for the mites, and if mites are present, they remove the larvae from the hive to prevent the spread of disease. That behavior is called “hygienic behavior,” Wagoner said.
Her research suggests that the chemical could be used as a tool to breed hygienic honey bee colonies that show increased hygienic behavior and are therefore more disease resistant hives.
Wagoner said she believes that if that specific chemical is sprayed over the top layer of all the honey bee cells in a hive, the nurse honey bees will uncap and check all the cells, increasing their chances of catching and emptying cells with the Varroa mites. Cells without mites will be recapped and the larvae left to develop normally.
“We think it will help reduce the parasite load of the colony,” Rueppell said.
And reducing the parasite load means reducing illness and death, leading to more honey bees to pollinate crops.
November 16, 2015 - ABJ Extra
How DNA and a Supercomputer Can Help
Sustain Honey Bee Populations
New multi-locus metabarcoding approach for pollen analysis
uncovers what plants bee species rely on
Botanical Society of America
To uncover what plants honey bees rely on, researchers from The Ohio State University are using the latest DNA sequencing technology and a supercomputer. They spent months collecting pollen from beehives and have developed a multi-locus metabarcoding approach to identify which plants, and what proportions of each, are present in pollen samples.
A single beehive can collect pollen from dozens of different plant species, and this pollen is useful evidence of the hive's foraging behavior and nutrition preferences.
"Knowing the degree to which certain plants are being foraged upon allows us to infer things like the potential for pesticide exposure in a given landscape, the preference of certain plant species over others, and the degree to which certain plant species contribute to the honey bee diet," says graduate student Rodney Richardson. "One of the major interests of our lab is researching honey bee foraging preferences so we can enhance landscapes to sustain robust honey bee populations."
For Richardson and his colleagues, metabarcoding is key to this research. It is a DNA analysis method that enables researchers to identify biological specimens.
Metabarcoding works by comparing short genetic sequence "markers" from unidentified biological specimens to libraries of known reference sequences. It can be used to detect biological contaminants in food and water, characterize animal diets from dung samples, and even test air samples for bacteria and fungal spores. In the case of pollen, it could save researchers countless hours of identifying and counting individual pollen grains under a microscope.
Richardson and his colleagues devised the new metabarcoding method using three specific locations in the genome, or loci, as markers. They found that using multiple loci simultaneously produced the best metabarcoding results for pollen. The entire procedure, including DNA extraction, sequencing, and marker analysis, is described in the November issue of Applications in Plant Sciences.
To develop the new method, the researchers needed a machine powerful enough to process millions of DNA sequences. For this work, the team turned to the Ohio Supercomputer Center.
"As a researcher, you feel like a kid in a candy store," Richardson says. "You can analyze huge datasets in an instant and experiment with the fast-evolving world of open source bioinformatics software as well as the vast amount of publicly available data from previous studies."
In previous metabarcoding experiments, the researchers worked solely with a marker found in the nuclear genome called ITS2. ITS2 successfully identified plant species present in pollen samples, but it could not produce quantitative measurements of the proportions of each.
While searching for something better, they decided to test two markers from the plastid genome. Pollen was previously thought to rarely contain plastids, but recent studies showed promise for plastid-based barcoding of pollen. Richardson and his colleagues found that the combined data from the two plastid markers, rbcL and matK, successfully correlated with microscopic measurements of pollen abundance.
The new multi-locus metabarcoding method involves all three markers and could serve as a valuable tool for research on the native bee species that comprise local bee communities.
"With a tool like this, we could more easily assess what plants various bee species are relying on, helping to boost their populations as well as the economic and ecological services they provide to our agricultural and natural landscapes." Richardson says, "While the honey bee is seen as our most economically important pollinator, it's only one of several hundred bee species in Ohio, the vast majority of which are greatly understudied in terms of their foraging ecology."
November 16, 2015 - ABJ Extra
The First Human Uses of Beeswax Have Been
Established in Anatolia in 7000 BCE
Nature is publishing the article in which the UPV/EHU lecturers Alfonso Alday and the late Lydia Zapata participated
University of the Basque Country
Neolithic vessels from Atxoste (Alava, Spain). Credit: A. Alday (UPV/EHU)
The current loss of bee populations as a result of pesticides, viruses and parasites has increased awareness about their economic importance and essential role in farming societies. Our relationship with bees stretches way back before modern farming, which is shown, for example, in various depictions in Ancient Egypt or, going back even further, in the prehistory of the Iberian Peninsula, as in the famous panel in the Araña rock shelter in Bicorp, Valencia. But in actual fact, until now we have had no direct information as to when and where our interest in bees and their products came about. This is what this piece of work is about.
Given that beeswax is a unique lipid complex, its 'biological footprint', which is fairly degradation resistant, can be identified in the study of the organic residues preserved in archaeological sites. With this aim in mind, the international research team led by the School of Chemistry of the University of Bristol, analysed ceramic vessels of the Neolithic period in the Near East, Europe and North Africa. "Now we know that beeswax was used continuously from the seventh millennium BCE, probably as an integral part in different tools, in rituals, cosmetics, medicine, as a fuel or to make receptacles waterproof," explained Alfonso Alday, lecturer in the Prehistory Area and, together with the late Lydia Zapata, a UPV/EHU participant in the research.
Farming emerged during the Neolithic era in various spots in the Middle East, and on occasions it had unexpected consequences: the opening up of forests to gain land and pastures encouraged the development of landscapes in which bushes and flowers provided environments suited to bees. In some way, the bees were the 'pursuers of agriculture', spreading their habitat as more farmland was being prepared.
The work on over 6,400 prehistoric vessels has specified the where and when of the first uses of beeswax. Now we know that the oldest evidence of it is to be found in Neolithic sites in Anatolia (Cayonü) in the seventh millennium BCE, in other words, corresponding to the oldest pottery cultures in the region. It is in this same area that the famous Çatalhöyük settlement is located and from which comes an ancient pictorial depiction of a bees' nest. The use of beeswax has also been detected in prehistoric populations in the north-west of Anatolia; it has been dated between 5,500 and 5,000 years BCE often mixed with the fat of ruminants.
In Europe the first known finds are somewhat later: in Greece around 4900-4500, in Rumania from 5500-5200 onwards, and in Serbia in 5300-4600. We are aware of its use round about the same time in Central Europe in the Neolithic culture of Austria and Germany. More recent are the French and Slovenian cases. On the Iberian Peninsula the 130 receptacles analysed have not preserved any remains of wax, so it is necessary to conduct further research given than in Levantine art there are various depictions of bees: "You have to bear in mind the fact that the detection of signs of lipids of the wax inside the vessels is very low and that the number of receptacles analysed in Iberia is still very low," but the logical thing is that the bees would also have found suitable environments to develop on the Iberian Peninsula since the beginnings of farming, in other words, about 5,500 years ago," added Alday.
On the other hand, in this work we have shown that in Denmark and in the British Isles the use of bee products was earlier than expected, while the absence of evidence above parallel 57 on the Eurasian Steppe is probably indicating to us the ecological limit of bee colonies.
November 13, 2015 - ABJ Extra
Cancellation Order Issued for Sulfoxaflor
On November 12, 2015, EPA issued a cancellation order for all previously registered Sulfoxaflor products. This cancellation order is in response to the September 10, 2015, order of the Ninth Circuit Court of Appeals finding that EPA improperly approved the Federal Insecticide, Fungicide, and Rodenticide Act registrations of the pesticide sulfoxaflor; the court’s order became effective on November 12.
Pursuant to EPA’s cancellation order, and beginning November 12, 2015, distribution or sale by the registrant of cancelled sulfoxaflor products is prohibited, unless such distribution or sale is for the purpose of disposal or export. Also, stocks of cancelled products held by persons other than the registrant may not be commercially distributed in the United States, but instead may be distributed only to facilitate return to the manufacturer or for proper disposal or lawful export. Use of existing stocks by end users is permitted provided such use is consistent in all respects with the previously-approved labeling for the product.
The Federal Food, Drug, and Cosmetic Act tolerances, also known as maximum pesticide residue levels for sulfoxaflor are not affected by either the court's decision or EPA’s cancellation order, so crops that have been properly treated with sulfoxaflor or that may be treated with existing stocks as described in the final cancellation order can still be sold legally.
November 12, 2015 - ABJ Extra
Ancient Bees Gathered Pollen in 2 Ways
This photo shows isolated pollen from the leg of ancient bee Protobombus messelensi. Credit: Engel and Wappler FIS MeI 6388.
Were ancient bees specialists, devoting their pollen-collecting attentions to very specific plant partners? Or were they generalists, buzzing around to collect pollen from a variety of flowers in their midst? Researchers who've studied an ancient lineage of bees now say in the Cell Press journal Current Biology on November 12 that the answer to both questions is yes. Bees living some 50 million years ago simultaneously relied on both strategies in foraging for pollen.
"Since the fossil record of bees extends to the Late Cretaceous, and an early bee-like ancestor is known from 100 million-year-old amber, it could very well be that this dual foraging behavior may be as old as bees themselves," says Conrad Labandeira of the Smithsonian Institution in Washington, D.C. and a fellow at the Paleontological Society. "If this is the case, then the controversy as to whether the earliest bees were generalist or specialist pollen collectors may be moot: the earliest bees during the mid-Cretaceous may have been simultaneously generalists and specialists!"
The researchers, led by Heisenberg Fellow of the German Science Foundation Torsten Wappler from the University of Bonn in Germany, identified pollen found on the bodies of eleven individuals from six bee species of the tribe Electrapini collected from two sites in Germany. The bee specimens were 44 to 48 million years old, with pollen well preserved across their bodies.
The researchers found pollen from a wide variety of nectar-producing flower types all across the bees' bodies--except, that is, on their legs. Pollen on the bees' hind legs came from a much narrower range of flower types, which the bees packed carefully into pollen baskets. That pollen was eventually taken to feed young bees back at the hive.
"Pollen retrieved by the second, specialized mode represented flowers that were considerably more morphologically stereotyped than the first mode and originated from only three or four major taxa of plants, unlike the considerably greater, more diverse spectrum of plants of the generalist mode that formed the pollination mutualism," Wappler explains.
The findings suggest that examples of one-for-one pollination--think yuccas and yucca moths or figs and fig wasps--are probably quite rare in nature.
"It may turn out that generalist pollination strategies in insects may be far more common than previously suggested," Labandeira says. "In the case of bees, the simultaneous presence of generalist and specialist pollen-collection strategies--now documented in deep-time bee and pollen fossils--likely renders the existence of specialist-only pollen collection modes a rare to very rare phenomenon."
They say researchers should now look for validation of the new findings in bee lineages that are even older.
November 9, 2015 - ABJ Extra
UC Davis Bee Researchers Write About
Bee Immunity and Toxin Metabolism
United States Geological SurveyWhen 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, three scientists at the University of California, Davis scientists have discovered.
The paper on bee immunity and toxin metabolism was published Nov. 9 in Scientific Reports, part of the Nature Publishing Group.
“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 Rachel Vannette of the UC Davis Department of Entomology and Nematology. “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.”
Kathy Keatley Garvey
UC Davis Department of Entomology and Nematology
November 5, 2015 - ABJ Extra
Native Field-foraging Bees Exposed to Neonicotinoid
Insecticides and Other Pesticides
United States Geological Survey
According to the first-ever study of pesticide residues on field-caught bees, native bees are exposed to neonicotinoid insecticides and other pesticides. This report was conducted by the U.S. Geological Survey and published in the journal Science of the Total Environment.
This research focused on native bees, because there is limited information on their exposure to pesticides. In fact, little is known about how toxic these pesticides are to native bee species at the levels detected in the environment. This study did not look at pesticide exposure to honey bees.
"We found that the presence and proximity of nearby agricultural fields was an important factor resulting in the exposure of native bees to pesticides," said USGS scientist Michelle Hladik, the report's lead author. "Pesticides were detected in the bees caught in grasslands with no known direct pesticide applications."
Although conservation efforts have been shown by other investigators to benefit pollinators, this study raises questions about the potential for unintended pesticide exposures where various land uses overlap or are in proximity to one another.
The research consisted of collecting native bees from cultivated agricultural fields and grasslands in northeastern Colorado, then processing the composite bee samples to test for 122 different pesticides, as well as 14 chemicals formed by the breakdown of pesticides. Scientists tested for the presence of pesticides both in and on the bees.
The most common pesticide detected was the neonicotinoid insecticide thiamethoxam, which was found in 46 percent of the composite bee samples. Thiamethoxam is used as a seed coating on a variety of different crops. Pesticides were not found in all bee samples, with 15 of the 54 total samples testing negative for the 122 chemicals examined.
Although this study did not investigate the effects of pesticide exposures to native bees, previous toxicological studies have shown that the chemicals do not have to kill the bees to have an adverse effect at the levels of exposure documented here.
For example, neonicotinoids can cause a reduction in population densities and reproductive success, and impair the bees' ability to forage. Follow-up research is now being designed to further investigate adverse effects at these exposure levels.
There are about 4,000 native species of bees in the United States. They pollinate native plants like cherries, blueberries and cranberries, and were here long before European honeybees were brought to the country by settlers. In addition, many native bees are quite efficient crop pollinators, a role that may become more crucially important if honey bees continue to decline.
This paper is a preliminary, field-based reconnaissance study that provides critical information necessary to design more focused research on exposure, uptake and accumulation of pesticides relative to land-use, agricultural practices and pollinator conservation efforts on the landscape. Another USGS study published in August discovered neonicotinoids in in a little more than half of both urban and agricultural streams sampled across the United States and Puerto Rico.
"This foundational study is needed to prioritize and design new environmental exposure experiments on the potential for adverse impacts to terrestrial organisms," said Mike Focazio, program coordinator for the USGS Toxic Substances Hydrology Program. "This and other USGS research is helping support the overall goals of the White House Strategy to Promote the Health of Honey Bees and Other Pollinators by helping us understand whether these pesticides, particularly at low levels, pose a risk for pollinators."
More information can be found on this paper at http://toxics.usgs.gov/highlights/2015-11-04-pesticides_bees.html. USGS research on the occurrence, transport and fate of pesticides can be found with the USGS Toxic Substance Hydrology Program webpage or the USGS Pesticide Fate Research project in California. Stay up to date with USGS Environmental Health science by signing up for our GeoHealth Newsletter at http://www.usgs.gov/envirohealth/geohealth/.
November 4, 2015 - ABJ Extra
We are Thankful for You, Honey!
(Courtesy of the National Honey Board)November officially kicks off the holiday season, the time of year when families are getting together to enjoy each other’s company, catch up and share stories, or even play a backyard football game. And what brings people together like a good meal?
We’re not sure about you, but there is just something about being home for the holidays that makes everything a little bit better, until it comes to the menu planning, that is. But fear not, we are here to make your Thanksgiving a little easier with these five delicious, honey-inspired recipes that are sure to be a hit with all the relatives and friends who are gathered around the family table!
Cinnamon Honey Glazed Sticky Buns
• 2 Tablespoons - butter or margarine, softened
• 1 loaf - frozen bread dough, thawed
• 1/3 cup - honey
• 1 teaspoon - cinnamon
• 1 cup - finely chopped pecans or walnuts
Grease 12 muffin cups with butter. Roll out thawed dough on lightly floured board to 12 x 8-inch rectangle. Mix honey and cinnamon. Using back of spoon, spread in even layer over dough. Sprinkle with nuts. Roll up dough, starting from long edge and end with seam on bottom. Cut dough roll using a gentle sawing motion into 12 equal-size buns. Place buns, spiral side up, in muffin cups. Cover with a piece of plastic wrap and let rise 30 to 60 minutes or until buns puff and fill cups. Bake at 350°F for 15 to 20 minutes or until golden. Remove from oven and carefully turn pan upside down onto board, letting syrup drip onto buns before removing them from pan.
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Honey-Glazed Sweet Potatoes
• 2 lbs. - sweet potatoes or yams
• 2/3 cup - orange juice
• 1/3 cup - honey
• 1 Tablespoon - cornstarch
• 1/2 teaspoon - ground ginger
• 1/2 teaspoon - ground nutmeg
• 1/4 teaspoon - salt
• 1 Tablespoon - butter or margarine
Wash and pierce potatoes or yams. Place on a piece of heavy-duty foil and bake at 375°F for 40 to 50 minutes until just tender. Cool, peel and cut into 1-1/2 inch pieces. Spray 8x8-inch baking dish with nonstick cooking spray. Place cooked potatoes or yams in dish; set aside. In small pan, combine orange juice, honey, cornstarch, ginger, nutmeg and salt. Stir until smooth. Cook over medium-high heat stirring until thick and mixture begins to boil. Stir and cook for one minute. Remove from heat and stir in butter. Pour over potatoes or yams stirring to coat. Bake at 350°F for 25 to 30 minutes until hot and potatoes are tender.
Printer Friendly Version - Honey-Glazed Sweet Potatoes
Chunky Apple Cranberry Sauce• 2 cups - fresh cranberries
• 2 - tart apples, peeled, if desired, cut in 1/4” slices
• 1 cup - chopped onion
• 1/3 cup - olive oil
• 1/3 cup - honey
• 4 teaspoons - red wine vinegar
• 1/4 teaspoon - ground ginger
• 1/4 teaspoon - ground cinnamon
• Freshly ground black pepper
In a medium saucepan stir all ingredients. Heat to a boil. Lower heat, cover and simmer 15 minutes; stirring occasionally. Cool and refrigerate.
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Honey Cornbread Stuffing
• 4 cups - day-old Honey Cornbread
• 1 (4 oz.) - Italian sausage
• 1 cup - chopped green bell pepper
• 1/2 cup - minced onion
• 1/2 cup - chopped celery
• 1 Tablespoon - minced parsley
• 1 teaspoon - dried thyme leaves, crushed
• 1 teaspoon - salt
• 1/4 teaspoon - ground black pepper
• 1/3 cup - chicken broth
• 2 Tablespoons - honey
In large bowl, place crumbled cornbread. Remove sausage from casing. In medium skillet, crumble and sauté sausage until brown. Using slotted spoon, remove sausage from skillet and add to cornbread. Drain all but 1 Tablespoon of fat. Return skillet to medium-high heat; stir in bell pepper, onion and celery. Sauté until vegetables are soft, about 5 minutes. Stir in parsley, thyme, salt and pepper. Cool slightly, then add to cornbread. In small bowl, combine broth and honey. Pour over stuffing. Place stuffing in a greased 9x9-inch baking dish. Cover dish with foil and bake at 350°F for 20 minutes. Remove foil and bake another 10 minutes until stuffing is lightly browned. As an alternative, pack you may pack stuffing into poultry cavity before roasting.
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Honey Pumpkin Pie
• 3 - eggs
• 1 - pastry for single 9-inch pie crust
• 3/4 cup - honey
• 1 can (15 oz.) - canned pumpkin
• 1 cup - evaporated milk
• 2 Tablespoons - flour
• 1 teaspoon - cinnamon
• 1/2 teaspoon - ginger
• 1/2 teaspoon - nutmeg
• 1/2 teaspoon - salt
Preheat oven to 425°F. In a medium bowl, beat eggs. Brush one teaspoon beaten egg on inside of pie crust. Place crust on a cookie sheet and bake for 5 minutes. Meanwhile, add the rest of the ingredients to remaining beaten eggs and whisk to combine. Remove pie crust from oven and carefully pour honey pumpkin mixture into hot crust; bake 5 minutes more at 425°F. Reduce heat to 350°F, and bake 30 to 40 minutes more, until filling is set. Cool completely and serve with Honey Whipped Cream.
For Honey Walnut Pumpkin Pie, just before serving, combine 1/3 cup honey, 1/3 cup chopped walnuts, and 1/4 teaspoon vanilla. Carefully spread over pie, cut and serve.
Printer Friendly Version - Honey Pumpkin Pie
November 4, 2015 - ABJ Extra
Urban Environments Boost Pathogen Pressure on Honey Bees
North Carolina State University
Researchers from North Carolina State University have found that urban environments increase pathogen abundance in honey bees (Apis mellifera) and reduce honey bee survival. The finding raises significant questions as urban areas continue to grow at the expense of rural environments, and urban beekeeping becomes more popular.
"We wanted to determine if the increased temperatures and impervious surface areas associated with urban environments have an effect on the number of pathogens bees are exposed to, and to the bees' immune responses," says Steve Frank, an associate professor of entomology at NC State and co-author of a paper on the work.
"We also wanted to look at both managed honey bee colonies and 'wild' ones, to see if that made a difference - and it did," says David Tarpy, a professor of entomology at NC State and corresponding author on the paper.
Working with volunteers, the researchers identified 15 feral colonies, living in trees or buildings without human management, and 24 colonies managed by beekeepers in urban, suburban, and rural areas within an hour's drive of Raleigh, N.C. The researchers collected worker bees from all of the colonies, and analyzed them to assess the bees' immune responses and their overall "pathogen pressure." Pathogen pressure accounts for both the types of pathogen species present and the abundance of those pathogens.
The research team found that colonies closer to urban areas and those managed by bee keepers had higher pathogen pressure.
"Overall, we found that the probability of worker [bee] survival in laboratory experiments declined three-fold in bees collected from urban environments, as compared to those collected in rural environments," Frank says.
However, the researchers also found that immune response was not affected by urbanization.
"Since immune response is the same across environments, we think the higher pathogen pressure in urban areas is due to increased rates of transmission," Tarpy says. "This might be because bee colonies have fewer feeding sites to choose from in urban areas, so they are interacting with more bees from other colonies. It may also be caused by higher temperatures in urban areas affecting pathogen viability or transmission somehow."
"Feral bees expressed some immune genes at nearly twice the levels of managed bees following an immune challenge," Frank says. The finding suggests that further study of feral bee colonies may give researchers insights that could improve honey bee management.
"Honey bees are important pollinators and play a significant role in our ecosystems and our economy," Tarpy says. "This work is really only a starting point. Now that we know what's happening, the next step is to begin work on understanding why it is happening and if the same negative effects of urbanization are hurting solitary, native bee species that are presumably more sensitive to their local environment."
November 2, 2015 - ABJ Extra
Study Explores What We Know About How
Neonicotinoids Affect Bees
University of Guelph
An international group of pollination experts - including a University of Guelph professor - has published a second summary in as many years on the scientific evidence about the effects of neonicotinoid pesticides on bees.
The report was published this week in Proceedings of the Royal Society B.
"The extent to which neonicotinoid insecticides harm bees and other insect pollinators is one of the most contentious questions that environmental policymakers have to grapple with today," said U of G environmental sciences professor Nigel Raine, who holds the Rebanks Family Chair in Pollinator Conservation.
More than 400 studies have been published on the topic in the last decade, often presenting variable or conflicting findings, making it difficult for farmers and policy-makers to make evidence-based decisions, Raine said.
He served on a team of researchers whose first scientific review of the evidence was published in May 2014.
Since then, more than 80 new studies have appeared. The team was asked to update its findings by the chief scientific adviser of the United Kingdom government, which has banned the use of three neonicotinoid insecticides.
"Our aim was to act as honest brokers, providing an account of the evidence, its strengths and limitations, but without making any direct policy recommendations," Raine said.
The two reviews provide a comprehensive overview of current scientific understanding of neonicotinoid impacts on pollinators. Such information must be considered within the broader context of the many, interacting factors affecting pollinator health, Raine said.
He added that despite plenty of research on aspects of this topic, policymakers have only limited evidence on how pollinator populations are affected by neonicotinoid use and on how farmers will respond to usage restrictions.
"Insecticides are designed to kill insect pests. Bees, and many other important pollinators, are also insects that will be killed by insecticides if exposure levels are high enough," Raine said.
What's being debated is the extent to which field levels of exposure have impacts on pollinators, he said.
"It varies enormously depending on many factors, including the type of insecticide, how it is applied and which pollinator species you consider. Current evidence suggests that bumblebees and solitary bees are more severely affected by neonicotinoids than honeybees."