New Tool Improves Beekeepers' Overwintering Odds and Bottom Line

PHYS.org By Kim Kaplan, US Department of Agriculture September 18, 2019

Credit: Lilla Frerichs/public domain

Credit: Lilla Frerichs/public domain

A new tool from the Agricultural Research Service (ARS) can predict the odds that honey bee colonies overwintered in cold storage will be large enough to rent for almond pollination in February. Identifying which colonies will not be worth spending dollars to overwinter can improve beekeepers' bottom line.

Beekeepers have been losing an average of 30 percent of overwintered colonies for nearly 15 years. It is expensive to overwinter colonies in areas where winter temperatures stay above freezing. So a less expensive practice of overwintering bee colonies in cold storage is becoming popular.

This new tool calculates the probability of a managed honey bee colony surviving the winter based on two measurements: the size of colony and the percent varroa mite infestation in September, according to ARS entomologist Gloria DeGrandi-Hoffman, who headed the team. DeGrandi-Hoffman is research leader of the ARS Carl Hayden Bee Research Center in Tucson, Arizona.

By consulting the probability table for the likelihood of a colony having a minimum of six frames of bees—the number required for a colony to be able to fulfill a pollination contract for almond growers come February—beekeepers can decide in September if it is economically worthwhile to overwinter the colony in cold storage.

"The size of a colony in late summer or early fall can be deceiving with respect to its chances of making it through the winter. Even large colonies with more than 12 frames of bees (about 30,000 bees) have less than a 0.5 probability (50 percent chance) of being suitable for almond pollination if they have 5 or more mites per 100 bees in September," DeGrandi-Hoffman said.

Even with this cost-cutting help, the research team found that revenue from pollination contracts by itself is not likely to provide a sustainable income to a beekeeper anymore. They followed 190 honey bee colonies and recorded all costs.

Considerable resources were expended to feed colonies and on varroa mite and pathogen control. Costs were about $200 per colony.

Almond pollination contracts paid an average of $190 per colony in 2019.

One way for beekeepers to remain economically viable as a business, is to produce a honey crop from their bees. This is most often facilitated by moving colonies to the Northern Great Plains where bees can forage for nectar and pollen from a wide variety flowering plants.

"The situation has changed a lot. It is more expensive to manage honey bees with costs to feed colonies when flowers are not available and to control varroa mites. And it is more difficult to find places for honey bee colonies that provide the diverse nutrition they need," said DeGrandi-Hoffman. "Pollination revenue alone is just not adequate for beekeepers to stay in business. But we need beekeepers because managed bees are a lynchpin in agricultural production today."

Successfully using cold storage will help beekeepers' bottom line, but we are really just learning what the best management practices should be with cold storage," she added.

https://phys.org/news/2019-09-tool-beekeepers-overwintering-odds-bottom.html

Honey Bee Colonies More Successful By Foraging on Non-Crop Fields

USDA-ARS By Kim Kaplan March 20, 2019

An adult worker bee gathering pollen and nectar from a helianthus flower. Credit: USDA-ARS

An adult worker bee gathering pollen and nectar from a helianthus flower. Credit: USDA-ARS

Honey bee colonies foraging on land with a strong cover of clover species and alfalfa do more than three times as well than if they are put next to crop fields of sunflowers or canola, according to a study just published in Scientific Reportsby an Agricultural Research Service (ARS) scientist and his colleagues.

Managed honey bee colonies placed from May until October next to land in the U.S. Department of Agriculture Conservation Reserve Program (CRP) in North Dakota were more robust with better colony health including higher numbers of bees and increased ability to turn nectar and pollen into vitellogenin—a compound that plays a number of roles including serving as the base for producing royal jelly, which bees use to nurture larvae and turn larvae into queens.

Vitellogenin also is a critical food storage reservoir for honey bee colonies, and a colony’s success in the spring depends on total vitellogenin reserves carried by specialized bees over the winter. Vitellogenin prolongs the lifespans of queens and forager bees as well as strongly influencing key behaviors that increase colony survival such as determining how old bees are before they begin foraging and whether they tend to gather nectar or pollen.

After spending six months foraging on CRP land and then overwintering, more than 78 percent of the colonies were graded A, the highest level commanding the highest price for pollination services in January, meaning a colony has six or more frames well filled with bees, capped cells and bee brood (larvae).

With colonies kept near intensely cultivated fields and then overwintered under the same circumstances to the CRP apiaries, only 20 percent could be rated Grade A and 55 percent were less than 2 frames or dead.

Land in the USDA Conservation Reserve Program provides valuable forage for honey bees. Credit: USDA-ARS

Land in the USDA Conservation Reserve Program provides valuable forage for honey bees. Credit: USDA-ARS

“With California almond growers having paid an average of $190 per Grade A colony in the 2018 almond pollination season, the need for beekeepers to have access to land that has diverse and substantial nectar and pollen sources is obvious,” explained ARS research microbiologist Kirk E. Anderson. Anderson is with ARS’ Carl Hayden Bee Research Center in Tucson, Arizona.

Anderson and his team, including ARS molecular biologist Vincent Ricigliano, also profiled several molecular colony level biomarkers, looking for a way to simplify how researchers can measure how well a honey bee colony is doing in different foraging conditions while overcoming individual bee variation.

They found that higher levels of vitellogenin stores were the best predictor of colony size after winter. Higher levels also were associated with increased production of antioxidant enzymes—which reduce cell damage—and greater production of antimicrobial peptides, which contribute to disease resistance.

The researchers eliminated other potential common causes of colony decline except for forage resource, highlighting the importance of pollen and nectar quality provided by the area surrounding the apiary. While the link between the quality of forage and colony health is generally known, this study highlights the value of agriculturally marginal (CRP) landscapes for honey bee production in a region that hosts close to half the U.S. managed bee population (about 1 million colonies) during the summer.

“We’ve also shown that the benefits of high-quality forage such as that provided by CRP land carries right through the overwintering period and leaves bees in the best shape to build up their numbers before being needed to pollinate almonds in February and early March,” said Ricigliano.

Our results provide land managers and scientists with methods to evaluate the relationship between bees and the landscape. For beekeepers, it provides a basis for making decisions about where to put their apiaries for the summer and fall after crop pollination ends so that the colonies will be in a position to build up robust healthy numbers in time for the migration to California for almond pollination, Anderson added.

The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impac

https://www.ars.usda.gov/news-events/news/research-news/2019/honey-bee-colonies-more-successful-by-foraging-on-non-crop-fields/

Newly Named Bacteria Help Honey Bee Larvae Thrive

PHYS.org   By Kim Kaplan  May 7, 2015

ARS technician Lucy Snyder selects bee larvae from honeycombs for in vitro rearing with probiotic bacteria. Credit: Vanessa Corby-Harris

Honey bees are under constant pressure from a whole host of stresses—diseases, poor nutrition, sublethal effects of pesticides, and many others. While researchers have been aware for a number of years of a community of bacteria in adult bees that may aid with some of these stresses, Agricultural Research Service researchers have identified the first bacteria that offer a benefit to bee larvae.

Molecular biologist Vanessa Corby-Harris and microbial ecologist Kirk E. Anderson at the ARS Carl Hayden Bee Research Center in Tucson, Arizona, have named a new species of bacteria—Parasaccharibacter apium. An Acetobacteraceae so far found only in honey bees and their hives, it appears to give honey  a significantly better chance of surviving to become pupae.

Honey bees have four major life stages: egg, larva, pupa, and adult.

Work on P. apium was initiated by an earlier post-doctoral researcher, Lana Vojvodic, who first discovered that these bacteria were abundant in larvae and also thrived in . Royal jelly is a protein-rich substance produced by adult bees in their hypopharyngeal glands, which resemble bunches of grapes on each side of the head. Nurse bees secrete and feed the jelly, which may contain P. apium, to young bee larvae. This jelly is the only food bee larvae eat during their first couple days. Then they are fed increasingly more honey, which has also been found to contain P. apium in most bee hives.

In lab experiments, ARS researchers tested honey bee larvae to see whether those fed royal jelly containing the Parasaccharibacter apium bacteria survived better those fed jelly that did not contain P. apium. Credit: Stephen Ausmus

In laboratory experiments designed by Corby-Harris, bee larvae were fed either P. apium-spiked jelly or sterile control jelly. The group fed P. apium had a 20-percent better survival rate in the first trial and a 40-percent better survival rate in the second trial.

"We haven't yet identified what P. apium does that confers this survival advantage to the larvae. It could involve the production of organic acids and lowering pH, which might have an antiseptic effect, or its presence might induce an immune response that could later work against larval pathogens," Corby-Harris says.

While P. apium found in honey bee hives is a distinct and new species from any previously identified, it has very close, naturally occurring relatives found in the nectar of many flowers, including cactus flowers, daisies, thistles, and apple blossoms.

Acetobacteraceae bacteria from flowers have not been tested yet to see if any of them might provide bee larvae with the same survival benefit, nor has there been a wider survey to determine the occurrence of P. apium-like species in economically important crops visited by bees.

A honey bee larva—the second life stage of honey bees in the egg, larva, pupa, adult sequence. Credit: Stephen Ausmus

"We have sequenced the genome of P. apium and begun to dissect the functional properties that distinguish flower-living Acetobacteraceaefrom those that have coevolved with the honey bee hive. Pinpointing these ecological differences will be key to understanding the function of P. apium in  hives," says Anderson.

With minimal sampling effort, P. apium was found in nearly every one of the healthy managed  examined by the researchers. A future study will explore the abundance of P. apium in weak or struggling managed bee colonies.

While the mechanism by which the bacteria benefit the larvae remains to be studied, the importance is clear enough that Corby-Harris and Anderson are already field testing its use as a management tool. "Along with P. apium, we are testing a number of bacteria that may benefit the pollination and honey-production industry," says Corby-Harris.

"More broadly, our research suggests that a community of bacteria that includes P. apium confers a generalized hygienic quality to the hive environment," says Anderson. "So we advise against unnecessary use of antibiotics by beekeepers, as it likely disrupts the variety and balance of microbial functions occurring throughout the hive, including the antiseptic properties of honey, pollen storage, larval health, and pathogen protection."

Read more at: http://phys.org/news/2015-05-newly-bacteria-honey-bee-larvae.html#jCp
 

Explore further: Age matters: Young larvae boost pollen foraging in honey bees