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Oldest Varroa tolerant honey bee population provides insight into the origins of the global decline of honey bees

View Article: PubMed Central - PubMed

ABSTRACT

The ecto-parasitic mite Varroa destructor has transformed the previously inconsequential Deformed Wing Virus (DWV) into the most important honey bee viral pathogen responsible for the death of millions of colonies worldwide. Naturally, DWV persists as a low level covert infection transmitted between nest-mates. It has long been speculated that Varroa via immunosuppression of the bees, activate a covert infection into an overt one. Here we show that despite Varroa feeding on a population of 20–40 colonies for over 30 years on the remote island of Fernando de Noronha, Brazil no such activation has occurred and DWV loads have remained at borderline levels of detection. This supports the alternative theory that for a new vector borne viral transmission cycle to start, an outbreak of an overt infection must first occur within the host. Therefore, we predict that this honey bee population is a ticking time-bomb, protected by its isolated position and small population size. This unique association between mite and bee persists due to the evolution of low Varroa reproduction rates. So the population is not adapted to tolerate Varroa and DWV, rather the viral quasispecies has simply not yet evolved the necessary mutations to produce a virulent variant.

No MeSH data available.


Geneious alignment of a 95 bp fragment amplified from all positive honey bee and mite samples aligned to DWV type A (pink).DWV types B (blue) and C (yellow) are also shown.
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f2: Geneious alignment of a 95 bp fragment amplified from all positive honey bee and mite samples aligned to DWV type A (pink).DWV types B (blue) and C (yellow) are also shown.

Mentions: The resulting fragments from HRM analysis were subjected to Sanger sequencing which confirmed that DWV had been amplified from all positive samples (Fig. 2). Variation was seen between samples but the dominant variant found in both bees and mites was closest to the type A variant (Fig. 2).


Oldest Varroa tolerant honey bee population provides insight into the origins of the global decline of honey bees
Geneious alignment of a 95 bp fragment amplified from all positive honey bee and mite samples aligned to DWV type A (pink).DWV types B (blue) and C (yellow) are also shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385554&req=5

f2: Geneious alignment of a 95 bp fragment amplified from all positive honey bee and mite samples aligned to DWV type A (pink).DWV types B (blue) and C (yellow) are also shown.
Mentions: The resulting fragments from HRM analysis were subjected to Sanger sequencing which confirmed that DWV had been amplified from all positive samples (Fig. 2). Variation was seen between samples but the dominant variant found in both bees and mites was closest to the type A variant (Fig. 2).

View Article: PubMed Central - PubMed

ABSTRACT

The ecto-parasitic mite Varroa destructor has transformed the previously inconsequential Deformed Wing Virus (DWV) into the most important honey bee viral pathogen responsible for the death of millions of colonies worldwide. Naturally, DWV persists as a low level covert infection transmitted between nest-mates. It has long been speculated that Varroa via immunosuppression of the bees, activate a covert infection into an overt one. Here we show that despite Varroa feeding on a population of 20–40 colonies for over 30 years on the remote island of Fernando de Noronha, Brazil no such activation has occurred and DWV loads have remained at borderline levels of detection. This supports the alternative theory that for a new vector borne viral transmission cycle to start, an outbreak of an overt infection must first occur within the host. Therefore, we predict that this honey bee population is a ticking time-bomb, protected by its isolated position and small population size. This unique association between mite and bee persists due to the evolution of low Varroa reproduction rates. So the population is not adapted to tolerate Varroa and DWV, rather the viral quasispecies has simply not yet evolved the necessary mutations to produce a virulent variant.

No MeSH data available.