Nosema in bumble bees

[snimmo243]

Bumblebees hit by honeybee diseases http://www.bbc.co.uk/news/science-environment-26242960

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[kevboab]

Very interesting. Just how are we supposed to keep the honeybees free of disease to protect the bumblebee. Nosema is rife everywhere.

[gavin]

Too late for Nosema ceranae but we could try to stop globalising every honeybee disease under the sun.

[kevboab]

Ha. You need a government wi baws to see that happen. Their too busy stealin cash fae folks oan benefits with empty rooms. Priorities !!!

[gavin]

Ha. You need a government wi baws to see that happen. Their too busy stealin cash fae folks oan benefits with empty rooms. Priorities !!!

Kev, we currently have two governments. One steals cash from folk with spare rooms from its base in the SE, and the other takes the lead on animal health including bees from Edinburgh. There's no chance that the one (mostly) responsible for animal health is going to grow baws as you say unless it starts getting a consistent message from Scotland's beekeepers that we are very concerned about the effects of historic and continuing importation of bee stocks from various places overseas. It even subsidises that activity with hardly a peep from our national organisation. If it does get a consistent and strong message then maybe something will happen. But as a community can we do it?

[gavin]

Very interesting. Just how are we supposed to keep the honeybees free of disease to protect the bumblebee. Nosema is rife everywhere.

Strangely the paper shows Nosema ceranae in Scotland more in the NW than the east, and Dwarf Wing Virus, the universal marker of Varroa infection, with a remarkably patchy distribution and only a 30-odd% prevalence. Anybody else think this is odd? Yet they then tried to correlate this with apparent disease in captured bumble bees. Maybe I should read it properly, but it doesn't completely add up, despite the prestigious journal publishing it.

[kevboab]

If it does get a consistent and strong message then maybe something will happen. But as a community can we do it?

To cut down on imports, beekeepers need a supply of queens/bees in place before that would ever happen. Operations in other parts of the world have no trouble breeding bees, so much so they have a surplus to supply the uk as well at very reasonable prices.

Until that happens nothing will ever change.

[mbc]

I dont see how dwv would jump hosts, very little opportunity as far as I can see as honeybees and bumbles dont really interact or mingle that much. Far more likely, in my opinion, would be that bumbles imported for pollination would spread tgheir pathogens to the local populations.
As far as border controls are concerned, UK's policy seems to be what might be termed "pragmatic", in that such vast amounts of assorted goods, plants and creatures cross our borders daily, it is accepted that little can be done to stop things coming in, and instead of any meaningful investment in proper bio security at borders, we have piecemeal contingency plans to "firefight" new incursions as they occur, just so the politicians can pretend that they give a shit.
With regard to licensed importation of livestock such as bees, Gavin is spot on with the need to provide the policy makers with a clear message to follow, this doesnt often happen. The answer has to be education, not only of the politicians, but also, and more importantly, the media, make something newsworthy and it soon shoots up the politicians priority list !

[The Drone Ranger]

Imported bumble bees might have less contact than we suppose with wild bees because they are employed in poly tunnels ?
When Sladen was trying to get his captive bumble bee queens to start laying he gave them some honey bee workers in the nest
Although research into bumble bee breeding began here I think it's mostly done elsewhere now hence the imported colonies
I don't know if honey bees are still used as part of the system of producing the bumble bee colonies
Sladen used to collect the overwintering queens from the wild and give them a nest plus some worker honeybees
Think I posted something on his book/pamphlet a while back

Here's how to make a nest for them
The old mouse nest might come from one of your beehives without a mouse guard :)
http://www.gardenersworld.com/how-to/projects/wildlife-gardening/how-to-make-a-bumblebee-nest/167.html

[greengumbo]

Strangely the paper shows Nosema ceranae in Scotland more in the NW than the east, and Dwarf Wing Virus, the universal marker of Varroa infection, with a remarkably patchy distribution and only a 30-odd% prevalence. Anybody else think this is odd? Yet they then tried to correlate this with apparent disease in captured bumble bees. Maybe I should read it properly, but it doesn't completely add up, despite the prestigious journal publishing it.

Something odd right enough about this study. 30% is very low 'prevalence'. They did find replicating virus though. Hmmmm.

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[gavin]

Something odd right enough about this study. 30% is very low 'prevalence'. They did find replicating virus though. Hmmmm.


GG (or anyone), how did they know the virus was replicating*? I saw the distinction in a supplementary table but didn't see their justification for discriminating the two.

I hear that they captured bees (Apis and Bombus) at the same site using a net. How can they be sure that they are not cross-contaminating samples at the point of collection?

I don't see why they used variables like number of sunshine hours to fine tune their model ....

'including biologically relevant interactions while controlling for latitude, longitude and sunlight hours, and adding collection site and species identity as random factors. Our full model for DWV presence fitted the data significantly better than the null model without any of the test predictors and their interactions included (likelihood ratio test: X2519.03, d.f.55, P,0.002). '

... sounds like tinkering, no? And are we really to believe that fine-scale local variations in DWV/Varroa presence on honeybees influences levels of virus in bumble bees in the same local area? If so, how? Surely a mile or so down the road beekeeping practice will be different and DWV/Varroa levels different? And are Varroa supposed to do this apparently wholesale Apis-Bombus disease transfer?

*PS
What I mean is the distinction made in the paper between virus which is just present from virus which is replicating.

[greengumbo]

Hey gavin....no idea why they do the all the control variables. It seems like fiddling around the edges to me as the model must be influenced by a million other things before considering sunshine etc. I'm not convinced that bumbles and honeybees come into contact much anyway. I wonder if a "DWV-like" virus is simply circulating in bumble bee populations anyway ? Much like DWV in honeybees was at benign levels until Varroa came on the scene ?

Anyway in the methods bit they say "we tested all of our DWV positive Bombus samples and a subset of DWV positive Apis samples for virus replication, a strong indicator for infection. DWV is a positive strand virus whose negative strand is only present in a host once the virus is actively replicating". So this is a bit technical BUT you do a reverse transcription using a specific DWV primer in your first strand synthesis. This then acts as the priming site for PCR and, importantly, would only show a product if you have detected negative strand virus...ie replicating virus. However you need to run a shed load of controls to be sure the original primer you used for tagging is not acting independently from the RT and giving you false positives. My bible....the BEEBOOK....has a chapter of virology in bees that talks about this.

[gavin]

Thanks GG. The issue of shed-loads of controls is the thing that worries me. They are making extraordinary claims (rapid, abundant, local intergenus viral transfer despite the lack of a convincing vector), and so the refereeing process should demand extraordinary levels of care. With the scant technical details available in a Nature paper you just can't judge the quality of the work. However word from some of those who have had a chance to debate this work prior to publication is that their results and conclusions were contentious, I hear.

One possible explanation for their results is, for example, that they cross-contaminated samples both way (Apis to Bombus and maybe vice versa) during or after collection. As you say, it seems conceiveable that species of Bombus could harbour their own strains of DWV-like viruses, just as Apis mellifera did before Varroa came along and amplified one variant.

Thanks for the comments on negative-strand virus copies indicating viral replication. If, say, Apis was actively replicating a certain virus and material (broken body hair for example) was transferred to other bees sampled in the same equipment is it conceiveable that the other bees would then have detectable replicating virus?