Latest varroa researches

[Finman]

Year 2012

CONTROL OF ECTOPARASITIC MITE VARROA DESTRUCTOR IN HONEYBEE (APISMELLIFERA L.) COLONIES BY USING DIFFERENT CONCENTRATIONS OF OXALIC ACID​

M. Rashid, E. S. Wagchoure, A. U. Mohsin*, S. Raja and G. Sarwar
Honeybee Research Institute, National Agricultural Research Centre, Islamabad, Pakistan
*Department of Entomology, PMAS University of Arid Agriculture, Pakistan
Corresponding Author: E-mail: [email protected]

ABSTRACT
The research work was carried out to determine the effects of oxalic acid (OA) on reducing ectoparasitic mite Varroa
destructor Anderson and Trueman (Acari:Varroidae) populations in honeybee Apis mellifera linguistica (Hymenoptera:
Apidae) colonies in the fall at Honey bee Research Institute, National Agricultural Research centre, Islamabad. Twenty
honeybee colonies were used in this experiment. Colonies were divided into four groups of five colonies each. Oxalic
acid was applied in sugar syrup with 4.2, 3. 2 and 2.1% concentrations. The OA with different concentrations was tricked
directly on the adult honey bees in between two frames using a syringe applied thrice on different dates at five days
interval. Average efficacy of OA with 3.2, 4.2 and 2.1 % was 95, 81 and 46 % respectively. No queens were lost, and
there was no adult honeybee mortality in any of the colonies during the experiment. It can be concluded that 3.2% OA concentration are very effectively control varroa mite and can be used without any side effect during broodless condition

 

[Finman]

.
Year 2007-2008

Dead or Alive: Deformed Wing Virus and Varroa destructor Reduce the Life Span of Winter Honeybees
Benjamin Dainata,
Jay D. Evansb,
Yan Ping Chenb,
Laurent Gauthiera and
Peter Neumanna,c

Author Affiliations
aSwiss Bee Research Centre, Agroscope Liebefeld-Posieux Research Station ALP, Bern, Switzerland
bUSDA-ARS Bee Research Laboratory, Beltsville, Maryland, USA
cDepartment of Zoology and Entomology, Rhodes University, Grahamstown, South Africa




ABSTRACT

Elevated winter losses of managed honeybee colonies are a major concern, but the underlying mechanisms remain controversial. Among the suspects are the parasitic mite Varroa destructor, the microsporidian Nosema ceranae, and associated viruses.

Here we hypothesize that pathogens reduce the life expectancy of winter bees, thereby constituting a proximate mechanism for colony losses. A monitoring of colonies was performed over 6 months in Switzerland from summer 2007 to winter 2007/2008.

Individual dead workers were collected daily and quantitatively analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV), N. ceranae, and expression levels of the vitellogenin gene as a biomarker for honeybee longevity.

Workers from colonies that failed to survive winter had a reduced life span beginning in late fall, were more likely to be infected with DWV, and had higher DWV loads. Colony levels of infection with the parasitic mite Varroa destructor and individual infections with DWV were also associated with reduced honeybee life expectancy.

In sharp contrast, the level of N. ceranae infection was not correlated with longevity. In addition, vitellogenin gene expression was significantly positively correlated with ABPV and N. ceranae loads.

The findings strongly suggest that V. destructor and DWV (but neither N. ceranae nor ABPV) reduce the life span of winter bees, thereby constituting a parsimonious possible mechanism for honeybee colony losses.

 

[Finman]

.


Journal of Invertebrate Pathology

Volume 101, Issue 1, April 2009, Pages 77–79

Deformed wing virus in western honey bees (Apis mellifera) from Atlantic Canada and the first description of an overtly-infected emerging queen

Geoffrey R. Williamsa,
Richard E.L. Rogersb,
Abby L. Kalksteinc,
Benjamin A. Taylora,
Dave Shutlera, , ,
Nancy Ostiguyc

Abstract
Deformed wing virus (DWV) in western honey bees (Apis mellifera) often remains asymptomatic in workers and drones, and symptoms have never been described from queens. However, intense infections linked to parasitism by the mite Varroa destructor can cause worker wing deformity and death within 67 h of emergence. Ten workers (eight with deformed wings and two with normal wings) and three drones (two with deformed wings and one with normal wings) from two colonies infected with V. destructor from Nova Scotia, Canada, and two newly-emerged queens (one with deformed wings and one with normal wings) from two colonies infected with V. destructor from Prince Edward Island, Canada, were genetically analyzed for DWV. We detected DWV in all workers and drones, regardless of wing morphology, but only in the deformed-winged queen. This is the first report of DWV from Atlantic Canada and the first detection of a symptomatic queen with DWV from anywhere.

 

[Finman]

Year 2007

Efficacy of repeated trickle applications of oxalic acid in syrup for varroosis control in Apis mellifera: Influence of meteorological conditions and presence of brood

Nicolaos Bacandritsosa, , ,
Iosif Papanastasioua,
Costas Saitanisb,
Antonio Nanettic,
Erifylli Roiniotia



Abstract

Oxalic acid field trails for the control of varroosis (Varroa destructor) were carried out in an apiary located on the Mt. Imittos (Attica, Greece). The colonies received four successive applications (approximately one every 16 days) with 4.2% oxalic acid (OA) and 60% sugar solution by trickling method with two alternative types of syringes (an automatic self-filling dosing and a single-use) from the broodright to broodless period.

The results indicate that the first three applications (from 6th October to 25th November—broodright period) resulted in 65.3% cumulative mite mortality, while only the last application (after the 26th November—broodless period) resulted in 77.3% mite mortality.

Very low outern temperatures reduce to the minimum the bee movability, which may result into a slower development of the OA efficacy. No poor colony growth or queen loss were observed even if the bee colonies were received the four successive OA applications with the last one taken place at a very low outern temperature (6.2 °C).

The trickling method using an automatic-filling syringe seems to be a very quick way for applying oxalic acid in large apiaries (approximately 150 hives/h).

 

[Finman]

.

Title: Status of bees with the trait of varroa sensitive hygiene (VSH) for varroa resistance

Authors

item Danka, Robert
item Harris, Jeffrey
item Ward, Ken - ALABAMA A&M UNIVERSITY
item Ward, Rufina - ALABAMA A&M UNIVERSITY


Submitted to: American Bee Journal
Publication Type: Popular Publication
Publication Acceptance Date: November 30, 2007
Publication Date: January 1, 2008
Citation: Danka, R.G., Harris, J.W., Ward, K., Ward, R. 2008. Status of bees with the trait of varroa sensitive hygiene (VSH) for varroa resistance. American Bee Journal 148(1):51-54

Technical Abstract:

The utility of USDA-developed Russian and varroa sensitive hygiene (VSH) honey bees, Apis mellifera L. (Hymenoptera: Apidae), was compared to that of locally produced, commercial Italian bees during 2004-2006 in beekeeping operations in Alabama, USA.

Infestations of varroa mites, Varroa destructor Anderson and Truman (Acari: Varroidae), were measured twice each year, and colonies that reached established economic treatment thresholds (1 mite per 100 adult bees in late winter; 5-10 mites per 100 adult bees in late summer) were treated with acaricides.

Infestations of tracheal mites, Acarapis woodi (Rennie) (Acari: Tarsonemidae), were measured in autumn and compared to a treatment threshold of 20% mite prevalence.

Honey production was measured in 2005 and 2006 for colonies that retained original test queens.

Throughout the three seasons of measurement, resistant stocks required less treatment against parasitic mites than the Italian stock.
The total percentages of colonies needing treatment against varroa mites were
12% of VSH,
24% of Russian and
40% of Italian.


The total percentages requiring treatment against tracheal mites were 1% of Russian, 8% of VSH and 12% of Italian.

The average honey yield of Russian and VSH colonies was comparable to that of Italian colonies each year.

Beekeepers did not report any significant behavioral problems with the resistant stocks. These stocks thus have good potential for use in non-migratory beekeeping operations in the southeastern USA.

 

[Finman]

Varroa destructor changes its cuticular hydrocarbons to mimic new hosts
Y. Le Conte, Z. Y. Huang, M. Roux, Z. J. Zeng, J.-P. Christidès, A.-G. Bagnères

Published 3 June 2015. DOI: 10.1098/rsbl.2015.0233

Abstract
Varroa destructor (Vd) is a honeybee ectoparasite. Its original host is the Asian honeybee, Apis cerana, but it has also become a severe, global threat to the European honeybee, Apis mellifera. Previous studies have shown that Varroa can mimic a host's cuticular hydrocarbons (HC), enabling the parasite to escape the hygienic behaviour of the host honeybees. By transferring mites between the two honeybee species, we further demonstrate that Vd is able to mimic the cuticular HC of a novel host species when artificially transferred to this new host. Mites originally from A. cerana are more efficient than mites from A. mellifera in mimicking HC of both A. cerana and A. mellifera. This remarkable adaptability may explain their relatively recent host-shift from A. cerana to A. mellifera.

 

[Finman]

.
Journal of Animal and Veterinary Advances
Year: 2012 | Volume: 11 | Issue: 24 | Page No.: 4519-4525
DOI: 10.3923/javaa.2012.4519.4525

Factors Limiting the Growth of Varroa destructor Populations in Selected Honey Bee (Apis mellifera L.) Colonies

Berna Emsen , Tatiana Petukhova and Ernesto Guzman-Novoa
Turkey

The whole text: http://docsdrive.com/pdfs/medwelljournals/javaa/2012/4519-4525.pdf

Abstract:

The objective of this study was to compare the hygienic behavior of worker bees (Apis mellifera) as well as infestation and reproduction parameters of the parasitic mite Varroa destructor between groups of honey bee colonies with high and low rates of Varroa population growth.

More than 150 colonies were screened for mite fall in early spring and again 16 weeks later.

The 10 colonies with the Lowest rates (L) and the 10 colonies with the Highest rates (H) of mite population growth were selected. These 20 colonies were evaluated for hygienic behavior, brood and adult bee infestation rates and mite reproduction in cells.

The amount of brood and the adult bee population of the selected colonies were also estimated. No differences were found between the two groups of colonies for brood or adult bee population or for hygienic behavior. However, significant differences were detected for mite infestation levels and for mite reproduction.

Brood and adult bee infestation rates in the colonies of the H group were 17 and 6 times higher, respectively than in the colonies of the L group. The proportion of reproductive mites was 0.92±0.05 in the H colonies vs. only 0.40±0.16 in the L colonies. Additionally, two times more immature mites were found in singly Varroa-infested cells of H colonies than in similarly infested cells of L colonies. Furthermore, the ratio of brood to adult bee infestation rate was 2.4 times greater for the H colonies in comparison with that of the L colonies.

These results indicate that brood-associated effects may influence the growth of varroa mite populations in honey bee colonies. The implications of these results are discussed

 

[Finman]

Date: 05 Mar 2015

A survivor population of wild colonies of European honeybees in the northeastern United States: investigating its genetic structure
Thomas D. Seeley,
David R. Tarpy,
Sean R. Griffin,
Angela Carcione,
Deborah A. Delaney




Abstract
There is a widespread belief that wild colonies of European honeybees have been eradicated in Europe and North America, killed by viruses spread by the introduced ectoparasitic mite, Varroa destructor. In reality, however, several populations of wild colonies of honeybees in Europe and North America are persisting despite exposure to Varroa. To help understand how this is happening, we tested whether the bees in one of these populations of wild colonies—those living in and around the Arnot Forest (NY, USA)—are genetically distinct from the bees in the nearest managed colonies. We found that the Arnot Forest honeybees are genetically distinct from the honeybees in the two apiaries within 6 km of the forest. Evidently, the population of Arnot Forest honeybees is not supported by a heavy influx of swarms from the nearest managed colonies, which implies that it is self-sustaining. These results suggest that if a closed population of honeybee colonies is allowed to live naturally, it will develop a balanced relationship with its agents of disease. Indeed, it is likely to become well adapted to its local environment as a whole. We suggest four ways to modify beekeeping practices to help honeybees live in greater health.

 

[Thymallus]

Nice work Finman. Will keep me going for hours.

 

[rook66]

http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2015186a.html

Nice to know research is on going, a long read but interesting.

 

[charlievictorbravo]

http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2015186a.html

Nice to know research is on going, a long read but interesting.

A long read indeed and a lot in there that the non-biologist will find difficult to follow but the conclusions were clear:

Abstract

Over the past 50 years, many millions of European honey bee (Apis mellifera) colonies have died as the ectoparasitic mite, Varroa destructor, has spread around the world. Subsequent studies have indicated that the mite’s association with a group of RNA viral pathogens (Deformed Wing Virus, DWV) correlates with colony death. Here, we propose a phenomenon known as superinfection exclusion that provides an explanation of how certain A. mellifera populations have survived, despite Varroa infestation and high DWV loads. Next-generation sequencing has shown that a non-lethal DWV variant ‘type B’ has become established in these colonies and that the lethal ‘type A’ DWV variant fails to persist in the bee population. We propose that this novel stable host-pathogen relationship prevents the accumulation of lethal variants, suggesting that this interaction could be exploited for the development of an effective treatment that minimises colony losses in the future.

What I found interesting and difficult to understand is that the research done on the Swindon Honeybee Conservation Group (SHCG) colonies showed a high prevalence of the DWV Type B, which by the process described as superinfection exclusion (SIE), prevented the more deadly DWV Type A from damaging the bees. The main claim to fame of the SHCG bees hitherto ( see http://www.swindonhoneybeeconservation.org.uk/hygienic-bees/ )is that they show hygienic traits - both grooming off or biting phoretic mites and removing brood infested with mites from cells - so this SIE seems to be in addition to these previously found physical hygienic behaviour traits. Was this a coincidence or is there some, as yet unidentified, link between hygienic behaviour and DWV Type B?

Answers on a postcard please!

CVB

 

[For want of a better word]

Coincidence... as other colonies of bees have shown intrinsic cleanliness behavior towards varroa mite... but do not appear to have the DWV type B?


More research needed!

Yeghes da

 

[jenkinsbrynmair]

Nice of Finny to share some research with us that leads towards a possibility of treatment free colonies

 

[pargyle]

Nice of Finny to share some research with us that leads towards a possibility of treatment free colonies

 

[pargyle]

Answers on a postcard please!

CVB

Optimist ... You'll need a stationer's full of postcards and all winter now that this ball's rolling ....

 

[Thymallus]

so this SIE seems to be in addition to these previously found physical hygienic behaviour traits. Was this a coincidence or is there some, as yet unidentified, link between hygienic behaviour and DWV Type B?

Answers on a postcard please!

CVB

To start the ball rolling........perhaps they survive because of the SIE of type B and not because of the claimed hygienic behavior. They could have, for example, claimed they survived because they used a Bee gym or a flea bay CD back scratcher or stood their hives on Lie Lines. Their (SHCG) science is not convincing nor accurate. For instance they call Deformed Wing Virus, Damaged wing virus. Hummmm.

Does this survival also equate with desirable characteristics wanted by beekeepers, like docility, honey yields etc?

 

[pargyle]

Their (SHCG) science is not convincing nor accurate. For instance they call Deformed Wing Virus, Damaged wing virus. Hummmm.

Does this survival also equate with desirable characteristics wanted by beekeepers, like docility, honey yields etc?

Hang on a minute .... Isn't this study conducted by a University over a period of years and produced as a peer reviewed paper ?

Isn't that what you usually cry out for when anything UNSCIENTIFIC is stated as helping the bees ?

What exactly about the research is not convincing ?

 

[charlievictorbravo]

To start the ball rolling........perhaps they survive because of the SIE of type B and not because of the claimed hygienic behavior. .... Their (SHCG) science is not convincing nor accurate. For instance they call Deformed Wing Virus, Damaged wing virus. Hummmm.

You're probably right about the SIE of DWV type B but it's possible that some other feature of the type B virus heightens the bees' ability to detect the mites that in other colonies go undetected because they (the mites) can mask their own smell and copy that of their host - hence the hygienic behaviour previously recorded. We've been thinking that hygienic behaviour is a genetic trait whereas it could be as a result of a feature of the DWV type B changing the bees' sense of smell in some way. Could the transmission of the virus between generations give the appearance of a generic trait? I don't know enough about virology to answer this question.

As for SHCG science not being convincing because of one spelling mistake on their website, it is barely worthy of comment. Everybody makes spelling mistakes, including you. It does not necessarily mean that everything you, or they, write is rubbish.

CVB

ps SHCG is the group of beekeepers (Swindon Honeybee Conservation Group) that has bred bees that show some hygienic behaviour. Their website is at http://www.swindonhoneybeeconservation.org.uk/research/

 

[Thymallus]

Hang on a minute .... Isn't this study conducted by a University over a period of years and produced as a peer reviewed paper ?

Isn't that what you usually cry out for when anything UNSCIENTIFIC is stated as helping the bees ?

What exactly about the research is not convincing ?

Swindon Honeybee Conservation Group (SHCG) research...not the paper. Read my post again and the one before it (the clue was in brackets (SHCG).....then read their web site where DWV= Damaged Wing virus......apologies will be accepted

 

[Thymallus]

You're probably right about the SIE of DWV type B but it's possible that some other feature of the type B virus heightens the bees' ability to detect the mites that in other colonies go undetected because they (the mites) can mask their own smell and copy that of their host - hence the hygienic behaviour previously recorded.

Nothing to suggest this might be the connection.
The hygienic behavior observed is apparently of bee bits seen on the varroa board and an extrapolation that this equates to hygienic behavior.

Spilling mistacks are one thing in the speed typing of the list, we all mak em, but confusing damaged with deformed is not a spelling mistake. It appears they either don't know the name of the virus or have not realizing they have labelled it wrongly. Either way it does not fill me with confidence that they have paid much attention to other important details in their claimed research. That's the SHCG web site, not the paper...
I could be wrong, it's just my opinion.