Bees with resistance to varroa mites

[prakel]

Not sure about the "if left alone ......resistance" bit
That's not what I felt they were trying to say

That's a quote attributed to Seeley who's also one of the authors of the paper.

[The Drone Ranger]

I just watched this and found it very interesting
I would say it probably puts to bed the notion that the bees will over time learn to deal with mites
Only one project but an impressive one

https://m.youtube.com/watch?v=fE4emUMyOWs

[The Drone Ranger]

I'm with mbc on this one. VSH and hygienic bees are not the same. I seem to remember Jeff Harris (Baton Rouge, VSH) saying that VSH bees do not uncap nitrogen frozen pupae and/or vice versa (or at least are no better than normal bees). His view is that VSH bees detect something volatile given off by Varroa damaged pupae.

One thing that worries me about Varroa resistance is the selection of less pathogenic mites, rather than 'better' bees. Has Ron Hoskins ever exposed his bees to a Varroa-infested hive from outside his area?

What about coordinated Varroa treatment? If everyone in an area treated all colonies simultaneously - for a full month with Apiguard or similar in the autumn and with OA in winter - it should leave the mites with nowhere to hide. It would have to be simultaneous and every colony because phoretic mites on drones or drifting workers mean that Varroa-free colonies are infested within days or at best weeks.

Not Varroa resistance I know, but I'm not sure that such a thing exists.

Hi Fatshark
Your predictions for Ron Hoskins work were prophetic
(although its his virus load that is less lethal not his mites)
Jeff Harris on the other hand is wrong ?
(American sites don't go there lol!)
"
I cant seem to get this video embeded in the post so here goes another try without the "help" of Tapatalk

[fatshark]

Suffering with a heavy cold and feeling miserable, so will watch the vid this afternoon with a hot toddy. Or two.

Interesting to look back through this thread and refs to Hoskins's bees and biting/grooming when the recent Schroeder paper describes them having an apathogenic strain of DWV 'blocking' replication (or perhaps infection?) by the virulent strain(s) of the virus. This process termed superinfection exclusion (SIE). The apathogenic strain is actually what was originally called VDV I think. Largely descriptive and requires testing, but it's another thing to consider. I worry about the 'stability' of isolated or closed populations and whether they have relevance in more apiary-saturated regions.

[gavin]

Viruses - who'd have 'em! I wonder if the SBA meeting passed some round, have one myself now. Thinking of ginger, lemon and honey.

Wouldn't it be ironic (or just neat) if the biting and grooming of the bee helps propagate the non-pathogenic virus in Varroa? OK, I can see the issues with that now. Maybe not. But it does seem possible that both the biting/grooming and the viral change interact somehow.

[Black Comb]

I missed the NHS 2013. That was an interesting lecture.
In 2014 Prof. Koeniger gave a lecture on the "varroa gate", a device to "scrub" off phoretic mites from bees from other colonies entering the hive. Perhaps he is onto something.
Caveat. His research was sponsored by Bayer.

[The Drone Ranger]

The Ghost in the hive is a long video but well worth watching
I think afterwards you will agree there is no biting or grooming of varroa going on
If there are any larva being removed its because the bees sense the larva is distressed or dying not that varroa is present

The immature mites and mite bits that are found on boards are almost always just part of the normal varroa cycle

The Ghost part of the title refers to the fact that the varroa are invisible to the bees whether on adult or larva
Hence the bees do nothing about them

Sorry to hear you are under the weather Gavin and Fatshark

[Pete L]

Sorry to hear you are under the weather Gavin and Fatshark

Likewise, hope you both get well soon.

[prakel]

The Ghost part of the title refers to the fact that the varroa are invisible to the bees whether on adult or larva
Hence the bees do nothing about them

It's still one of my favourite Honey Show videos to date so thanks for reminding me to watch it again.

There is of course a window when the mites are visible to their host:

Our results confirmed the findings reported in Nation et al. (1992) that chemical mimicry of V. destructor changes as the parasite switches hosts. Varroa destructor is the first case, known to us, in which a parasite frequently switches its camouflage as it moves between host stages. Because groups of individuals within an A. mellifera colony can vary in their CHC profile, due to life stage (Falcón et al. 2014; Kather et al. 2011), a passive chemical camouflage is likely to be the best strategy to facilitate a quick adjustment in the parasite’s camouflage to match the new host with minimal energetic cost. The mite also has a number of appendages, such as suckers, hairs, and its crab-like carapace (Rosenkranz et al. 2010) that allow it to hold onto the host during the transition time of mimicking one host stage to mimicking that of a new one. This way, these appendages likely buy the mite the few hours needed for it to blend in fully with the host’s CHC profile.

Evidence for Passive Chemical Camouflage in the Parasitic Mite Varroa destructor by Ricara Kather et al

http://www.wnklba.co.uk/app/download...JCE+Varroa.pdf

[gavin]

I think afterwards you will agree there is no biting or grooming of varroa going on
If there are any larva being removed its because the bees sense the larva is distressed or dying not that varroa is present

Au contraire DR, biting and grooming have been demonstrated for around 28 years. I don't know why the Sheffield researchers were reluctant to include it in the range of responses of bees to Varroa.

https://scholar.google.co.uk/scholar...1%2C5&as_sdtp=

Hygienic behaviour is, as you say, bees sniffing out distressed larvae and removing them. Varroa Sensitive Hygiene is when bees are particularly good at doing it for Varroa-infested cells.

Grooming and biting is different. Dr Kather's research demonstrates nicely that Varroa is capable of shifting to stealth mode in terms of odour but bees still can find and damage them. That link above gives you 10 papers that discuss this.

Here is a bee very much aware of the mite on it.

https://www.youtube.com/watch?v=Nfn4jwqUqvI

And another that successfully gets one off.




Thanks for the concern folks. Just a winter virus, lots of folk have it just now.