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Viral Degeneration of Queen Honeybee Ovaries and an MEA Philosophy

Infection by these viruses does not necessarily result in ovarian degeneration, and additional factors are likely involved. The general decline of managed colonies of Honeybees by beekeeper's in Europe and the US, as well as other regions of the globe, is an increasing challenge to beekeeper's. Among numerous possible causes involved in colony weakness, death and poor Queen fertility principally, resulting in untimely and sometimes costly re-queening events.

Image from Honeybeesuite.com


A Queen's fertility is extremely important to the hive as any beekeeper will tell you. Without the Queen having an adequate fertility the colony could collapse, weaken and not produce a good honey crop at the end of the year. Research has been done to see what viral loads were present that could lead to a Queen laying eggs poorly. The researchers who published their academic paper to PLoSONE had very good results in their study and were able to make some definitive headway in establishing what happens to Queen Honeybees when they are exposed to high levels of viral loads.


Even with the Queen's all having Deformed Wing Virus (DWV), they were not all at a level that led to problems with a Queen's ovaries and therefore her fertility. The study cocluded that other factors had to be at play that ultimately led to the viruses being able to infect the ovaries and cause degeneration of the tissues that led to Queen infertility and failure.


The study also found no correlation between Queen age and ovarian degeneration.


The study was conducted in France with further information gleamed from a separate survey conducted in the US.


Paraphrased from the study: Any factor affecting Queen fertility will stagnate a colonies development, increasing its susceptibility to opportunistic pathogens.


Degenerated follicles characterized by discoloration (see image below) and lesions, or scar tissue if you will, were universally associated with egg-laying deficiencies in the Queen. In figures A and B you will see yellowing of the ovaries which indicates that a Queens ovaries are starting to degenerate and are experiencing follicle degeneration.



Image from PLoSONE article cited at bottom of article.


A DNA analysis showed two high on the list of detected viruses. DWV and Varroa destructor Virus 1 (VDV-1), with a higher prevalence in mated Queens than in virgin Queens.


Although it must be noted that no significant correlation could be made between the viral load and the ovaries degeneration or egg-laying deficiency among the wider population of Queens.


Infection by these viruses does not necessarily result in ovarian degeneration, and additional factors are likely involved. The general decline of managed colonies of Honeybees by beekeeper's in Europe and the US, as well as other regions of the globe, is an increasing challenge to beekeeper's. Among numerous possible causes involved in colony weakness, death and poor Queen fertility principally, resulting in untimely and sometimes costly requeening events.


It has been shown that the high juvenile hormone in Queen larvae prevents the induction of programmed cell death in the ovaries at the onset of metamorphosis. Which may play a role in the ability later to diminish viral desiccation of tissues.


In France, queens were found to be infected with DWV, VDV-1, Black Queen Cell Virus (BQCV), Isralei Acute Paralysis Virus (IAPV) and Sac Brood Virus (SBV), while in the US queens were found with DWV, BQCV, SBV, Chronic Bee Paralysis Virus (CBPV) and Kashmir Bee Virus (KBV) from a single Apiary. Both surveys had a high incidence of c0-infection, 83% in France survey's and 93% in the US survey.


DWV was 100% in both surveys, meaning all Queens sampled were positive for the virus. BQCV was detected in 63% of populations sampled in France and 86% in the US. SBV was shown to be lower in French samples over American.


Viruses from this and other studies shows a regional and apiary specific difference, owing to climactic differences as the most likely cause. Virus detection was frequently higher in the abdomen of the Queen instead of the ovaries, suggesting that other tissues such as fat body and gut where this virus was previously identified may be the primary tissue for replication.


This observation that DWV actively replicates in multiple tissues involved in egg production, such as the fat body and the ovaries, suggests that DWV could have a major impact on Queen fertility.


Total viral loads and overall hive health from other factors plays a role in Queen fertility, and therefore, a Queen's genetics cannot always be blamed for a combination of external factors that can lead to Queen fertility issues.


A beekeeper must be able to determine in this changing world if climate and bee forage is also to blame for the failure of a Queen. Our over dependence on chemicals can certainly weaken a Queen who takes in high amounts of food to keep up with the production of successive generations in order to maintain a hives strength and foraging abilities. These factors combined can lead to detrimental effects that extend throughout a colony and could lead to collapse, weakening or overall poor performance.


Too quick are beekeepers to blame their Queen or the genetics of her offspring without taking into account the factors that are also at play outside the hive as well as in the hive. There are so many connections that can lead to many affects that they must not be discounted. Beekeepers must learn to be able to evaluate the environment that their bees are living and foraging in before making clear conclusions about what's happening with a hive.


My philosophy is this, we must learn to take in many factors as to why a colony fails, why a queen fails before we start to blame the genetics. In the world of nature the web of life has so many connections that we can not single out any one cause without certainty. Clearly, based upon this study we can see that there are many factors that determine if a Queen is going to experience degeneration of her ovaries, age is not necessarily a factor. It has only been in recent decades that beekeepers have changed their management to re-queen their hives every year, or every other year. What has changed in the ecological/biological landscape that forced this change? What data do we have available to make a conclusion? Are there apiaries where this is not frequently the case? How are they managed?


At the Mystic Earth Apiary, we will be helping to answer these questions as we conduct research studies along side our operations, as information is our most powerful weapon in combating diseases, pests, problems and logistics.


We hope this review of an academic article, which will be featured much more in depth in our book has been enlightening for you. Thanks for reading.


Source: Gauthier L, Ravallec M, Tournaire M, Cousserans F, Bergoin M, Dainat B, Joachim R. de Miranda (2011) Viruses Associated with Ovarian Degeneration in Apis mellifera L. Queens. PLoSONE 6(1):e16217.doi:10.1371/journal.pone.0016217


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