Bees Throw Out Mites

Bees Throw Out Mites

September 11, 2009 By Alfredo Flores

ARS researchers have developed honey bees that more aggressively deal with varroa mites, a parasite that is one of the major problems damaging honey bees today.

Honey bees are now fighting back aggressively against Varroa mites, thanks to Agricultural Research Service (ARS) efforts to develop bees with a genetic trait that allows them to more easily find the mites and toss them out of the broodnest.

The parasitic Varroa mite attacks the honey bee, Apis mellifera L., by feeding on its hemolymph, which is the combination of blood and fluid inside a bee. Colonies can be weakened or killed, depending on the severity of the infestation. Most colonies eventually die from varroa infestation if left untreated.
Varroa-sensitive hygiene (VSH) is a genetic trait of the honey bee that allows it to remove mite-infested pupae from the capped brood—developing bees that are sealed inside cells of the comb with a protective layer of wax. The mites are sometimes difficult for the bees to locate, since they attack the bee brood while these developing bees are inside the capped cells.

Audio Podcast: The Mitey Bee Bouncers

ARS scientists at the agency’s Honey Bee Breeding, Genetics and Physiology Research Unit in Baton Rouge, La., have developed honey bees with high expression of the VSH trait. Honey bees are naturally hygienic, and they often remove diseased brood from their nests. VSH is a specific form of nest cleaning focused on removing varroa-infested pupae. The VSH honey bees are quite aggressive in their pursuit of the mites. The bees gang up, chew and cut through the cap, lift out the infected brood and their mites, and discard them from the broodnest. This hygiene kills the frail mite offspring, which greatly reduces the lifetime reproductive output of the mother mite. The mother mite may survive the ordeal and try to reproduce in brood again, only to undergo similar treatment by the bees.
To test the varroa resistance of VSH bees, the Baton Rouge team conducted field trials using 40 colonies with varying levels of VSH. Mite population growth was significantly lower in VSH and hybrid colonies than in bee colonies without VSH. Hybrid colonies had half the VSH genes normally found in pure VSH bees, but they still retained significant varroa resistance. Simpler ways for bee breeders to measure VSH behavior in colonies were also developed in this study.
This research was published in the Journal of Apicultural Research and Bee World.
Provided by Agricultural Research Service

Honeybee Decline Slows Slightly

Discovery Reports:
May 20, 2009 -- The decline of honeybee colonies has slowed slightly since last fall, but a mysterious combination of ailments is still decimating the insect's population, federal researchers say.

U.S. Department of Agriculture researchers found that honeybee colonies declined by 29 percent between September 2008 and early April. That's an improvement over the last two years, when researchers found that 32 percent and 36 percent of all beekeepers surveyed lost hives.

Domestic honeybee stocks have been waning since 2004 because of a puzzling illness scientists called colony collapse disorder, which causes adult bees to inexplicably forsake their broods. Bees now appear also to be suffering from other ailments.

Honeybees help pollinate many fruits and vegetables, including blueberries, tomatoes, apples and almonds.




The disorder has killed off the weakest colonies in recent years, and now pesticide drift and old foes such as the parasitic varroa mite are more likely threatening those that survived, said Jerry Hayes, a former president of the Apiary Inspectors of America, whose members helped carry out the survey.

"Whether it's CCD or pesticides, fungicides or chemicals affecting how the queens respond, I don't know that beekeepers care," said Hayes, chief of the apiary sector of the Florida Department of Agriculture. "The ones who I talk to are just beside themselves. If you are a small business person how many years of 30 percent losses can you take?"

Regardless of the cause, bees are still dying at rates that could put some keepers out of business, said Jeff Pettis, the USDA's top bee scientist.

The survey released Tuesday included 787 beekeepers who account for 20 percent of the country's approximately 2.3 million commercially managed bee hives. The data -- collected through a spring telephone survey in which researchers polled keepers about how many of their hives survived the fall and winter, when queens go dormant -- is being prepared for submission to a journal.

The Russian bee

One of the newer bee stocks in the U.S. was imported from far-eastern Russia by the U.S. Department of Agriculture’s Honey Bee Breeding, Genetics, and Physiology Laboratory in Baton Rouge, Louisiana. The researchers’ logic was that these bees from the Primorski region on the Sea of Japan, have coexisted for the last 150 years with the devastating ectoparasite Varroa destructor, a mite that is responsible for severe colony losses around the globe, and they might thrive in the U.S. The USDA tested whether this stock had evolved resistance to varroa and found that it had. Numerous studies have shown that bees of this strain have fewer than half the number of mites that are found in standard commercial stocks. The quarantine phase of this project has been complete since 2000, and bees of this strain are available commercially.

Russian bees tend to rear brood only during times of nectar and pollen flows, so brood rearing and colony populations tend to fluctuate with the environment. They also exhibit good housecleaning behavior, resulting in resistance not only to varroa but also to the tracheal mite.

Bees of this stock exhibit some unusual behaviors compared to other strains. For example, they tend to have queen cells present in their colonies almost all the time, whereas most other stocks rear queens only during times of swarming or queen replacement. Russian bees also perform better when not in the presence of other bee strains; research has shown that cross-contamination from susceptible stocks can lessen the varroa resistance of these bees.

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North Carolina Cooperative Extension Service

Distributed in furtherance of the acts of Congress of May 8 and June 30, 1914.

Check out the different types of honey bees

http://www.beesource.com/resources/usda/the-different-types-of-honey-bees/

What can the beekeeper do to provide for winter survival?

Before hard weather arrives and temperatures drop to freezing, there is work to be done.

Take off surplus supers, if the bees don’t need the space, remove them. If you are working with an 8 frame brood box and only 4 frames are being worked, take off the super.

Provide for entrance reducers to keep other animals out, especially mice, they need somewhere warm to be as well.

Place pollen patties in hives for additional protein and remember to feed your bees in the fall so they can store up food for the winter. Placing liquid syrup out of the hive will not help as much when the weather doesn’t permit them to move the syrup into the hive.

You must use caution when choosing the method to feed them because feeding them in the hive invites robbers and other animals. But when temperatures are at a low feeding them in the hive by a method that would put the sugar syrup or crystals in the very back would be preferable.

Russian Honey Bee Project Cooperators

The scope of the Russian honey bee trials is large, involving several cooperators. There are two reasons for needing these cooperators. First, the trials require more honey bee colonies than the laboratory can possibly maintain on its own. Each year the tests require more than 500 colonies of honey bees. Second, in order to produce a stock of commercially valuable honey bees, tests need to be conducted in several different beekeeping environments so that lines selected for inclusion into the program are known to have value in more than one location.

Our cooperators are very patient with the peculiar needs of researchers. We need to do things to the test colonies that are not necessarily helpful to them. We sometimes need to work them to the bottom board during a nectar flow. We almost always need to have colonies that have varroa mites and sometimes we need to let control colonies die or almost die in order to get good test data. Our cooperators are incredibly patient and tolerant of requests that go against common beekeeping good sense, sometimes harm their colonies, even causing some to die, and almost always reducing their honey production. These cooperators are essential to our breeding program. It would be far less effective without them.

http://www.russianbreeder.org/coop.htm

A Comparison of Russian and Italian

A Comparison of
Russian and Italian
Honey Bees
American beekeepers have been using Italian honey bees (Apis
mellifera ligustica) since they were first imported to the New World in
1859. The standard German honey bee (A. m. mellifera), which had
been in America for more than 200 years, was by that time ill-tempered,
disease-ridden, and less suited for honey bee management. Conversely,
the Italian bees were and are excellent honey producers, show a gentle
temperament that makes them the most popular race of honey bee in
North America, have a moderately low tendency to swarm, and have a
bright yellow color that makes queens easy to find.
ut Italian honey bees are susceptible
to two deadly parasitic mites,
the tracheal mite (Acarapis woodi) and
the varroa mite (Varroa destructor),
which were introduced into the U.S. in
1984 and 1987, respectively. Colonies
contract these mites through equipment
sharing and overcrowding, and, once
infested, entire colonies can succumb
within one or two years. Beekeepers
have relied largely on pesticides to
control the mites, but many of these
chemicals can contaminate the honey
and beeswax in a hive. The mites also
are becoming increasingly resistant to
the pesticides, making the chemicals
less reliable and, eventually, ineffective.
The high colony mortality that accompanies
these two mites is a serious
concern of the bee industry today, and
various types of bees are continually
being examined with an eye toward
finding a hardy, productive stock that
can resist them.
B
Russian Bee Project
Efforts to find a honey bee that is genetically resistant to
the varroa and tracheal mites led researchers at the USDA
Honey Bee Research Laboratory in Baton Rouge, Louisiana,
to Russia. There, on the far eastern side of that vast
nation, in the coastal Primorski region around Vladivostok,
they found what they sought—a promising strain of Apis
mellifera. These Russian bees had been exposed to varroa
mites for approximately 150 years, much longer than other
Apis mellifera strains had, and the researchers surmised
that the Russian bees could have developed a resistance
to the mites. Indeed, subsequent research has shown that
these Russian bees are more than twice as resistant to varroa
mites than other honey bees. Moreover, they are highly
resistant to tracheal mites, the other mortal enemy of bees.
Russian bees also tend to produce as much honey as standard
bee stocks, if not more.
A number of American queen breeders now produce Russian
queens for sale. These breeders are located all across
the country, but most are concentrated in the South and in
California. Many of the Russian queens on the market are
hybrid daughters of a breeder queen openly mated to any
drone, which may come from a variety of stocks within
two miles of a particular mating yard. The resulting colonies
are genetic hybrids. Recent research has suggested the
hybrids are only partially resistant to mites, but studies at
North Carolina State University show that partial resistance
is statistically significant when the hybrids are compared to
Italian bees.
Production of pure Russian queens can be guaranteed only
by truly isolating the breeding grounds, as has been done at
the USDA’s bee laboratory on Grand Terre Island, 25 miles
off the coast of Louisiana. Here the drone stock is also
controlled.
Management of Russian bees
Russian bees are quite different from standard Italian bees
in several ways (Table 1):
• Russian bees do not build their colony populations
until pollen is available, and they shut down brood
rearing when pollen is scarce. This characteristic
makes them suitable in areas where the main honey
and pollen flows occur later in the year, such as the
mountains of North Carolina. By contrast, Italian bees
maintain a large brood area and worker population
regardless of environmental conditions. This trait can
result in more bees than the hive can feed and may
lead Italian colonies to early winter starvation. It also
explains the Italian bee’s tendency to rob other colonies
of their honey stores.
• Russian colonies maintain active queen cells through
out the brood-rearing season. In Italian colonies, the
presence of queen cells is interpreted by beekeepers
as an attempt to swarm (reduce overcrowding by
establishing a new colony) or to supersede (kill and
replace) the resident queen. This is not the case with
Russian colonies, as the workers often destroy the
extra queen cells before they fully develop.
• Russian bees can vary in color, but they are generally
darker than the Italians.
Requeening Italian hives with Russian queens can be difficult,
and many beekeepers lose their newly introduced Russian
queens. Russian queens have a different “odor” than
Italians, and parent colonies must become acclimated to
this odor before they will accept the newcomers. Beekeepers
who intend to go from Italian to Russian bees should
requeen a colony in the fall by splitting the hive in two with
the use of a double screen (see highlighted information).
This will permit the odors to mix but, at the same time,
prevent the workers from interacting with the new queen.
The old Italian queen should be kept in the lower half, and
the new Russian queen should be placed in the upper half
in a cage. If a separate entrance is provided to the upper
half, only young nurse bees will enter the top portion, and
the older foraging bees will return to the lower hive.
Table 1. A comparison of various colony characteristics of Italian and Russian honey bees
Characteristic Italians Russians
Varroa mites More susceptible More resistant
Tracheal mites More susceptible Highly resistant
Brood rearing Continuous throughout the summer Usually only during times of pollen availability
Robbing High Low
Queen cells Only during swarming or queen replacement Present most of the time
Pollination skills Small difference from Russian bees Small difference from Italian bees
Temperament Gentle, less defensive; not likely to sting Gentle, less defensive; not likely to sting
Color Light Dark
The Russian queen should be released from her cage after
seven to ten days and permitted to lay eggs for four weeks.
During this time, the odor of the Russian queen will comingle
with that of the Italian colony. If the Russian queen
continues to lay eggs and is being tended by the workers,
she has been accepted. After this acclimation period,
the Italian queen can be removed, and the colony can be
reunited. If the workers do not accept the new queen during
the four weeks of acclimation, the requeening process has
failed, and the workers kill her. But the colony will still
have the original Italian queen, and the entire hive will not
be lost.
Hybrid bees tend to lose their initial desirable traits over
subsequent generations. Because many commercial Russian
bees are hybrids, the queen should be marked with
paint to distinguish them from succeeding generations.
If the colony contains an unmarked queen, she is probably
homegrown and a second-generation hybrid and should be
replaced with a new marked Russian queen as soon as
possible to preserve the hive’s resistance to the mites.
When requeening a Russian colony with a Russian queen,
it probably will not be necessary to use the extended acclimation
period outlined above. Queens usually come in
the mail in cages made of wood and wire-mesh. The exit
hole is blocked with a hard candy-like substance that the
bees must eat through to release the queen. This usually
takes several days, after which the queen has acquired the
colony “odor” and is readily accepted by the workers. As
noted above, requeening an Italian honey bee colony with a
Russian queen takes longer because of the Russian queen’s
very different odor.
Conclusion
Russian honey bees can be a valuable tool in controlling
the depredations of varroa and tracheal mites and also in
reducing, but not necessarily eliminating, the need for
chemical treatments to control these mites. However, the
beekeeper must understand how to manage bees of this
new stock properly, as they are quite different from the
widely used Italian honey bees.
Suggested reading
De Guzman, L. I., T. E. Rinderer, G. T. Delatte, J. A.
Stelzer, L. Beaman, and C. Harper. (2001). An evaluation
of far-eastern Russian honey bees and other methods for
the control of tracheal mites. American Bee Journal, 141:
737-741.
Harris, J. W., and T. E. Rinderer. (2004). Varroa resistance
of hybrid ARS Russian honey bees. American Bee Journal,
144: 797-800.
Rinderer, T. E., L. I. de Guzman, G. T. Delatte, and C.
Harper. (2003). An evaluation of ARS Russian honey bees
in combination with other methods for the control of varroa
mites. American Bee Journal, 143: 410-413.
Rinderer, T. E., L. I. de Guzman, and C. Harper. (2004).
The effects of co-mingled Russian and Italian honey bee
stocks and sunny or shaded apiaries on varroa mite infestation
level, worker bee population and honey production.
American Bee Journal, 144: 481-485.
Requeening Italian colonies with Russian queens
The requeening procedure has frustrated many beekeepers because standard introduction techniques often
are not successful when requeening Italian colonies with Russian queens, as the colonies may reject the new
queens. Italian bee colonies need more time and separation to become acclimated to Russian queens.
Step 1: Split the colony in half, with the two halves separated by a double screen.
Step 2: Place the old queen in the bottom half and a caged Russian queen in the upper half.
Step 3: Release the Russian queen from her cage after 7 to 10 days.
Step 4: Once the Russian queen has been accepted and has laid eggs for one month, kill the old queen,
and reunite the two halves (remove the screens).
Prepared by
David R. Tarpy
Department of Entomology, North Carolina State University
and
Jeffrey Lee
Commercial Beekeeper, Lee’s Bees, Mebane NC
2,000 copies of this public document were printed at a cost of $509.50 or $0.25 per copy.
Published by
NORTH CAROLINA COOPERATIVE EXTENSION SERVICE
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. North Carolina State University and North Carolina A&T State University commit
themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two
Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T State University, U.S. Department of
Agriculture, and local governments cooperating.
5/05—2M—JL/DB AG-655
E05-44559
STATE UNIVERSITY
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This project received support from The Golden LEAF Foundation.

What does gene expression have to do with CCD?

Review: Johnson et al. (2009). Proceedings of the National Academy of Science, 106: 14790-14795

Written: October 7, 2009

Posted: 10/07/09

Word count: 749

Question: What does gene expression have to do with CCD?

Answer: Some novel insights into the possible mode of action

In case you’ve been sailing around the world for the last three years or otherwise have been without any human or media contact, honey bees have been facing some serious problems lately. Most notorious of these is a largely mysterious ailment termed Colony Collapse Disorder, or CCD, since the hallmark symptom is a rapid depopulation of the adult worker force. Purported culprits abound, but none has yet to really emerge as the front runner. Scientists have therefore been busily working on trying to find the underlying cause or causes, using various approaches that range from beekeeper surveys to colony bioassays. Another approach that several groups have taken is a genetic approach, since genes are a large part of what bees are.

Genes are something that we inherit from our parents, encoded in our DNA. Each gene codes for a protein, and the combination of all of these gene products is what makes us what we are. The pathway to making proteins from DNA is the central dogma of genetics: DNA is transcribed into RNA, and then RNA is translated into proteins. The place where RNA translation takes place, the “protein factories” in us all, are called ribosomes (more on that later). Following this process of transcription and translation, genes can be highly regulated, each being turned on or off or tuned up or down, depending on the needs of the organism. You can imagine, therefore, that the entire genome of any living thing is like a huge panel of toggle switches that get flicked on and off to deal with whatever challenges a critter might face.

Patterns of gene expression—this panel of toggle switches—can be a powerful tool to understand the effect that something has on an organism (such as disease, toxins, etc…). It is this genomic approach that a research team from the University of Illinois, lead by Reed Johnson, took to elucidate the effects of CCD on bees across all of their genes. They tested three sets of bees—one sampled from the East coast (which included both healthy and CCD bees), one sampled from the West coast (which also included both healthy and CCD bees), and one “historical” sample collected prior to the onset of CCD (which were presumably all healthy). They then compared which genes were up- or down-regulated as a consequence of being in these various groups.

The researchers found considerable variation in the different sources of bees. In other words, there were many differences in gene expression just simply based on whether the bees were from the East, West, or Historical. But, when accounting for the geographic differences, they were able to isolate 65 genes that might be potential markers for CCD (and therefore provide clues as to what might be causing it). Of that gene set, few were genes associated with detoxification enzymes, which suggests that there isn’t much of a connection with pesticide exposure with the expression of CCD. Similarly, there was no clear trend in genes associated with immune response, which suggests that there was no clear connection with any one disease agent and CCD.

Johnson and his colleagues, however, did find something unusual. They detected many small fragments of ribosomal RNA, the skeletal structure of the “protein factories” that translate RNA into protein. They speculate that these fragments might be caused by some of the viruses that infect bees, including Deformed Wing Virus (the calling card of varroa mites) and Israeli Acute Paralysis Virus, which can interfere with protein production by breaking up ribosomes. Thus these findings suggest a potential mode of action for CCD, namely viruses causing protein production and colony ill health.

While this study is more of a starting point than a conclusion, it does illustrate the power of looking at the whole genome to determine mechanism. Of course, more work will need to be done to verify this putative link. To paraphrase one of the authors in a media interview, this may not be the smoking gun, but it just might be the bullet wound.