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Wednesday, March 3, 2010

Varrao Mite responsible for bee colony deaths and colony collapse disorder








"An Ontario researcher has identified a main cause in the decline of the province's
 honeybee colonies over the last three years -- the varroa mite."

"The mysterious decline of honeybee colonies across the northern hemisphere has consumed bee researchers over the last three years as they try to determine what is causing it."

"In a study published in last month's issue of the apiculture journal Apidologie, University of Guelph professor Ernesto Guzman found that the majority of honeybee colony deaths in Ontario could be traced to the varroa mite.
Guzman and his research team studied 408 bee colonies across southern Ontario over three seasons, from the fall of 2007 to the early summer of 2008. Twenty-seven per cent of the colonies examined in the fall were dead by the spring. Of the colonies that died, Guzman and his team found that 85 per cent of colony deaths could be attributed to the varroa mite."

"The varroa mite was by far the main culprit of these mortality cases," Guzman told CTV.ca in a telephone interview Wednesday.

"The other four factors examined were the colonies' food reserves in the fall, the size of the colonies and the impact of two other parasites on bee populations. The study found that colony size and fall food reserves also had an impact on colony death."
In combination with a small colony size and low fall food reserves, the varroa mite creates "a perfect storm for the colony to die," Guzman said.


This is great news, because now ways of controlling these mites can be undertaken by scientists. I found this interesting article which describes another way of controlling the mite:

"Varroa mites could literally be walking into a trap—thanks to a new attractant developed by Agricultural Research Service (ARS) scientists in Gainesville, Fla."


The 1/16-inch long parasite, Varroa destructor, is a top pest of honey bees nationwide, hindering the beneficial insects' ability to pollinate almonds, blueberries, apples, zucchini and many other flowering crops."



"At the ARS Chemistry Research Unit in Gainesville, research leader Peter Teal and colleagues are testing a bait-and-kill approach using sticky boards and natural chemical attractants called semiochemicals."
"In nature, Varroa mites rely on these semiochemicals to locate—and then feed on—the bloodlike hemolymph of both adult honey bees and their brood. Severe infestations can decimate an affected hive within several months—and rob the beekeeper of profits from honey or pollinating services. But in this case, the mites encounter a more heady bouquet of honey bee odors that lure the parasites away from their intended hosts and onto the sticky boards, where they starve."
http://www.sciencedaily.com/releases/2009/07/090705145109.htm



"New products to combat the varroa mite will help the problem, Guzman said. He recommended breeding bees with a genetic resistance to the mite and using bio pesticides that will kill the mite but not the bee as potential methods to curb this problem."

The varroa mite has been a pest Ontario's beekeepers have had to consider for about 20 years, but it seems to have developed resistance to the chemicals beekeepers have used to control the problem, Guzman said.

 "The disease caused by the mites is called varroatosis."


"Varroa destructor can only replicate in a honey bee colony. It attaches at the body of the bee and weakens the bee by sucking hemolymph. In this process the mite spreads RNA viruses like deformed wing virus (DWV) to the bee. A significant mite infestation will lead to the death of a honey bee colony, usually in the late autumn through early spring. The Varroa mite is the parasite with the most pronounced economic impact on the beekeeping industry.Mites reproduce on a 10-day cycle. The female mite enters a honey bee brood cell. As soon as the cell is capped, theVarroa mite lays eggs on the larva which hatch into several females and typically one male. The young mites hatch in about the same time as the young bee develops and leave the cell with the host. When the young bee emerges from the cell after pupation the Varroa mites also leave and spread to other bees and larvae. The mite preferentially infests drone cells.The adults suck the "blood" of adult honey bees for sustenance, leaving open wounds." You can read about control measures for the mite by clicking on the following link: 
http://en.wikipedia.org/wiki/Varroa_destructor 
(which is also the source of the information in the paragraph directly above).
According to research I have done online concerning the Varrao Mite, 
this insect was first introduced into North America via Florida in 1987.


"Varroa mites were originally found only in Asia as parasites on the Asian honeybee (Apis cerana).  Until recently, all varroa mites were classified as Varroa jacobsoni, a species first characterized in Java in 1904 and later discovered to inhabit much of mainland Asia.  Genetic analysis, however, has identified two distinct species in this range.  The "new" species, christened Varroa destructor, is endemic to Korea, Japan, and Thailand.  Of the two, V. destructor has been definitively identified as the variety involved in current infestations of European honeybees."


"V. destructor has spread to every continent except Australia and is widely distributed throughout world apiculture, absent only in Australia, Hawaii, and central Africa.  Although  they have recently been found on other insects (including the bumblebee  Bombus pennsylvanicus), varroa mites can only reproduce when  associated with honeybees and thus are considered harmless to  other insects." 



 "A single mite was discovered in Maryland in 1979; however, no more were seen in the U.S.
until populations were discovered in Wisconsin and Florida in 1987."
Mode(s) of Introduction: "The host shift from Asian to European honeybees first occurred 

when Apis mellifera was brought East for apiculture and presumably came into contact with 
Apis cerana.  These "introduced" European honeybees were then purportedly taken from 
Asia back into Eastern Europe by amateur beekeepers in the Russian Army, bringing the
parasite with them.  Subsequent introductions into other continents and areas are also
assumed to have occurred via the shipping of bees for apiculture."
Reason(s) Why it has Become Established: "Apiculture provides an ideal situation for

the establishment and persistence of a parasite like the varroa mite.  Honeybees are raised
in very high-density hives, allowing for similarly high densities of mites.  Because of this,
commercial beehives can maintain extremely damaging infestations that would normally run 
their course quickly in most populations.  It is hypothesized that the slower development of 
Apis mellifera relative to Apis cerana also contributes to a faster growth of infestations
(as the female is given more time to lay more eggs on the developing larvae).  Once it has
become introduced in a region, the mite spreads quickly between bee colonies, giving it
access to many novel infestation sites.  It is thought that contact between drones outside of 
their respective hives is responsible for this spread, though transport on secondary hosts such 
as the bumblebee may also be a factor.  Unlike a bacterial or viral epidemic, the spread of
varroa does not necessarily spread immunity in its wake, and only a few resistant strains of
A. mellifera have been identified, leaving most commercial bees open to re-infestation even
if they have already been treated for varroa.  Finally, although control is possible in
commercial hives and much money and effort has been spent in extirpating apicultural
infestations, the mite has
spread to wild honeybees which are not as tightly controlled, providing a reservoir for 
re-infestation of cultured bees."
Ecological Role: "V. destructor is a parasite, and thus may serve some role in population

control of wild bees.  In its original host, the partially resistant Asian honeybee, the mite 
causes much less mortality than in its introduced hosts, suggesting that the original host-parasite 
relationship was more stable and normalized."
Benefit(s): "Varroa mites could possibly be used as a biological control mechanism for

introduced honeybees, and are already decimating feral populations in the Americas. 
However, some of the more worrisome strains, such as the Africanized "killer" bee, show 
resistance to varroa infestation."
Threat(s): "Varroa mites are extremely damaging to honeybee colonies.  While the mites 

alone may cause some mortality by simply feeding off of larvae and adults, they mainly kill by 
acting as disease vectors for native infections like acute paralysis virus and Paenibacillus 
larvae.  They spread these agents in a manner similar to the mosquito, transferring bodily
fluids from one host to the next.  By crippling adults and killing potential workers at the larval stage, 
varroa infestation weakens the colony, leaving it open to conquest by other colonies or the
eventual death of the infested colony due to lack of maintenance.  In temperate climates, varroa mite
infestation typically kills an entire colony within three to four years, though in warmer areas 
such as Florida death can occur within seven months. 
The loss of cultured bees is a serious economic burden for the apiculture industry because of
both loss of honey for sales and increased spending on control.  The loss of feral and native 
honeybees in the Americas and Europe (respectively) through varroa infestation has been even 
more pronounced than in apiculture, with up to 90% of wild colonies lost in some areas and 
local extirpation possible in more isolated ecosystems, such as the British Isles.  While less
immediately economically damaging than infestation among cultured bees, loss of the plant
species pollinated by these bees is potentially a much greater disaster for both agriculture and
biodiversity."
-------------------------------

If Africanized killer bees are for some reason immune 
to this mite, hopefully scientists who study these insects
can determine why this is the case so that possibly this immunity
could be transferred to honey bees in the future. The future
of the World's flowers and the World's food 
we obtain as a consequence of the pollination
activities of honey bees are both being threatened by these mites.
http://www.columbia.edu/itc/cerc/danoff-burg/invasion
_bio/inv_spp_summ/varroa_dest
ructor.html
"Bees play an integral role in the world food supply, and are essential for the
pollination of over 90 fruit and vegetable crops worldwide, with the
  economic value of these agricultural products placed at more
 than $14.6 billion in the U.S. In addition to agricultural crops,
 honey bees also pollinate many native plants within the ecosystem.
 Recently, the increased deaths in bee colonies due to CCD seriously
 threaten the ability of the bee industry to meet the pollination needs
of fruit and vegetable producers in the U.S." (source: http://www.viewzone.com/lostbees22.html )






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Thoughts worth thinking about

"Our subconscious minds have no sense of humor, play no jokes and cannot tell the difference between reality and an imagined thought or image. What we continually think about eventually will manifest in our lives."-Sidney Madwed



Laws alone can not secure freedom of expression; in order that every woman and man present their views without penalty, there must be spirit of tolerance in the entire population.- Albert Einstein Too often we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring, all of which have the potential to turn a life around. - Leo Buscaglia



A person's true wealth is the good he or she does in the world. - Mohammed



Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein



The best way to find yourself, is to lose yourself in the service of others. - Ghandi



The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves. - Helen Keller



Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns



Life is as dear to a mute creature as it is to man. Just as one wants happiness and fears pain, just as one wants to live and not die, so do other creatures. -His Holiness The Dalai Lama



Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude towards those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it. -



Milan Kundera, The Unbearable Lightness of Being



The worst sin towards our fellow creatures is not to hate them, but to be indifferent to them. That's the essence of inhumanity. -George Bernard Shaw

Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.