Untreated feral hives, what they can do

[Finman]

In dreams wild hives (queen marked or not) fight against varroa, but what they really do is....



Journal of Apicultural Research
April 2011

Invasion of Varroa destructor mites into mite-free honey bee colonies under the controlled conditions of a military training area


Eva Frey, Hanna Schnell and Peter Rosenkranz

Abstract

The honey bee mite Varroa destructor can be spread between colonies by vertical transmission, particularly when heavily infested colonies are robbed by foraging bees from neighbouring hives. We quantified the invasion of V. destructor into mite free colonies on a military training area not accessible to other beekeepers. Ten "mite receiver colonies" continuously treated against V. destructor were placed at distances of one to 1.5 km from four heavily infested "mite donor colonies". Over a two month period from August to October, the population of bees, brood, and V. destructor in the donor colonies were estimated at three week intervals and the invasion of V. destructor into the receiver colonies was recorded every 7-12 days. During the experimental period, between 85 and 444 mites per colony were introduced into the receiver colonies. There were no significant differences in the invasion rates in relation to the distance between donor and receiver colonies. In total, 2,029 mites were found in the 10 receiver colonies, but these only correspond to 2.5% of the total mite population in the donor colonies at the start of the experiment. This means that the major part of the initial V. destructor population died together with the collapsed host colonies. Under natural conditions, a more benign behaviour should therefore be an adaptive strategy for V. destructor. From a practical perspective we could show that highly infested honey bee colonies present a substantial risk to already treated colonies up to distances of 1.5 km away.

 

[pargyle]

In dreams wild hives (queen marked or not) fight against varroa, but what they really do is....



Journal of Apicultural Research
April 2011

Invasion of Varroa destructor mites into mite-free honey bee colonies under the controlled conditions of a military training area

Ten "mite receiver colonies" continuously treated against V. destructor were placed QUOTE]

Hi Finman - I really respect your knowledge and the wealth of extremely helpful information that you bring to this forum but ... 10 colonies continuously treated against Varroa ... are hardly feral colonies. Whilst I am on the fence about the use of some chemical treatments one has to question what sort of condition the treated colonies were in and whether a truly feral and uninfected colony would have fared better in resisting mite invasion in this study ... the study really needed a better control model than this and the conclusion drawn is clearly skewed.

 

[Chris B]

but ... 10 colonies continuously treated against Varroa ... are hardly feral colonies.

Of course not but you are missing the point. The 4 infested colonies represent feral colonies and the effect they have on managed colonies.
It's often referred to as reinvasion. I'm not sure the study proves or disproves anything except that mites can easily migrate from one colony to another.

 

[Finman]

[

Ten "mite receiver colonies" continuously treated against V. destructor were placed QUOTE]

Hi Finman - I really respect your knowledge and the wealth of extremely helpful information that you bring to this forum but ... 10 colonies

continuously treated against Varroa ... are hardly feral colonies.

... the study really needed a better control model than this and the conclusion drawn is clearly skewed.

You are as right as one hive owner can be

No one has said that hives in reseach were ferals.

They were carefully nursed hives and moved to a military area.

I add that feral to the headfline because that happened in NZ. Even if you treated you hives carefully, a hive may get a huge mite load from dying hive.

In Australia AFB infect nursed hives at same way.

Actually feral bees are escaped swarms. They have same genepool as surrounding hives.

When varroa spreaded in Finland 20-30 years ago, it moved 50 km in a year from Russian border to west frontier. Half of Norway is still uncontaminated.

 

[Finman]

I'm not sure the study proves or disproves anything except that mites can easily migrate from one colony to another.

It proves only to those who allready knows that. This is an old phenomenom descriped in New Zealand.

Others can believe what ever.

People tend to believe that every swarm in a chimney or at last in granpa barn are survivors. That is why I put that reseach into forum.

Here is lots of guys who recommends " do nothing to varroa" because no one help those "ferals".


DON'T KILL OTHER'S DREAMS BUT STILL, KILL MITES!

 

[domino]

You are as right as one hive owner can be

To be fair he's as right as anyone who read the title can be. But now you've pointed out that these aren't meant to represent feral hives but uninfected ones it's all good.

 

[alanf]

I'm not sure the study proves or disproves anything except that mites can easily migrate from one colony to another.

I think a significant line in the abstract is: "There were no significant differences in the invasion rates in relation to the distance between donor and receiver colonies." One of the frequently repeated warnings is the spread of disease by 'drifting' of workers between neighbouring hives in an apiary. The movement of varroa described suggests that it's anywhere within range that matters. If disease is about it can move much more rapidly and widely than just to immediate neighbours.

One implication is that it is not going to be worthwhile scourging every last varroa out of a colony if there are untreated colonies within a significant radius. Early autumn varroa treatments, for instance thymol in August, could still see a couple of hundred arrive after treatment. Given the current mild autumns in the UK that's potential for a thousand or so varroa by January in a hive that ended August almost varroa free. Thymol is less effective if it's applied late because of temperature but it's less effective if applied early because of re-infection. Not an obvious choice and one that will vary by conditions each year.

Even treating a whole apiary at the same time is not effective if others a Km or more away time it differently. Being the only beekeeper for miles around has advantages.

 

[rolande]

Even treating a whole apiary at the same time is not effective if others a Km or more away time it differently.

Blatant cut and paste here from Beesource (http://www.beesource.com/forums/showthread.php?276950-something-to-think-about), a post by Michael Palmer from a couple of days ago addressing this very issue.

Boy, isn't that the truth of the matter. The "we" and the "not we" camps aren't helping to move this discussion forward. I apologize to all if you're offended by what I say, but...most of the folks here with strong opinions haven't kept bees long enough, haven't got enough bees, or enough apiaries spread out across the countryside to have a valid opinion. "One man's opinion of moonlight". You can talk about pet theories, or dogma gleaned from the internet, but if you haven't experienced a crash from sloppy neighboring beekeepers, you just don't have a right to be critical.

I can show you two beautiful apiaries that crashed from varroa because a new beekeeper in between doesn't know how to manage his varroa population...let alone his bees. My other apiaries roll ones and twos, but these two 13s and 15s. And how about a yard of 75 nucleus colonies that went down because a neighboring beekeeper's sick packages were allowed to crash from nosema. And he blamed ME for HIS losses. GMAB.

So you folks that need to point fingers, etc, remember this. I love my bees as much as you love yours. Beekeepers with 10,000 colonies care as much about their bees as beekeepers with 10. We're a community folks, if we don't drive it apart. Let's be respectful of each other, and aware that what we do in our own bees, whatever dogma it is we believe, is effecting the whole neighborhood. We're all in this together.

 

[Dishmop]

I'm more inclined to think that colonies died because a load of people kept opening the hives and somehow counting all the mites inside. I dont see any mention of what time period this occured over.

1 year? 5? 10?

 

[Finman]

I think a significant line in the abstract is.......

You understood very well that information.

The more to south beekeeping goes, the more difficult it is control varroa.
Mites are in safe under cappings. South USA, NZ, South Africa, whole Africa in future, Argentina...
they are all in troubles when treating their hives.

Just now varroa spreads in Africa faster than forest fire
http://www.apitradeafrica.org/varroa-in-africa.html

 

[johncorne]

I dont see any mention of what time period this occured over.

1 year? 5? 10?

It says "Over a two month period from August to October"

Jc

 

[Dishmop]

Well I saw that but I just dont believe that the "donor" colonies died out over that period. All four of them? Heavily infested? I assume that as is par for the course in such tests the colonies were infested to saturation point by those carrying out the tests.

 

[pargyle]

You are as right as one hive owner can be

No one has said that hives in reseach were ferals.

They were carefully nursed hives and moved to a military area.

I add that feral to the headfline because that happened in NZ. Even if you treated you hives carefully, a hive may get a huge mite load from dying hive.

In Australia AFB infect nursed hives at same way.

Actually feral bees are escaped swarms. They have same genepool as surrounding hives.

When varroa spreaded in Finland 20-30 years ago, it moved 50 km in a year from Russian border to west frontier. Half of Norway is still uncontaminated.

OK Finman - I stand corrected in terms of interpretation of what the study sought to achieve - but I still think that it lacked a serious control model - and the only thing the study really proved was that Varroa can spread rapidly and that uninfected hives can get infected.

What I am more interested in ... is there an alternative (even in the longer term) to continuing chemical treatment of hives. We know that some Varroa have already developed a resistance to some treatments and with their reproduction rate are capable of Darwinian evolution at a tremendous pace. So ... when we finally find that the current range of varroa treatments are no longer effective what do we do next ?

I was reading this old (1999) Swiss study which looked at acaricides being present in comb and (amongst other conclusions) there were concerns that this latent contamination was having an effect on the resistance building up in Varroa.

See : www.agroscope.admin.ch/imkerei/01810/01822/index.html?

So ... as it is 14 years since this study have there been any alternative solutions put forward ? Or do we keep beating the 'chemical only' drum ?

And only having one hive does not preclude me from reading and thinking as much as the next Beek with a thousand hives - indeed, as a relative newcomer I probably spend more time reading, thinking and worrying !

 

[Finman]

OK Finman - I stand corrected in terms of interpretation of what the study sought to achieve


What I am more interested in ...!

I do not know what they tried but than phenomenon was described in NZ news when varroa occupied the country.

I could imagine that researchers wanted to simulate those stories with the reseach where start points were well known.

 

[Finman]

.

That example is a little bit like ABF research.

There were 10 pure hives in the yard. They feeded AFB contaminated honey to one hive.
After some days every 10 hives had AFB spores.

 

[domino]

Well I saw that but I just dont believe that the "donor" colonies died out over that period. All four of them? Heavily infested? I assume that as is par for the course in such tests the colonies were infested to saturation point by those carrying out the tests.

There is another study in the same publication by a well known US queen breeder. That showed a 60% mortality rate in untreated hives during a year. Only three out of eight of those control hives survived, in a trail on the efficacy of non chemical varroa treatments. That's similar to other control hives survival rates, a study in Sweden showed a 75% mortality rate in untreated hives in the first year. Those hives were seeded with ~150 mites per hive.

I don't think it's too far fetched to believe that in that study all of the colonies would die in the first year. Given the survivability of the donor hives wasn't even a factor of the study they have no reason to misrepresent it.

 

[Dishmop]

I don't think it's too far fetched to believe that in that study all of the colonies would die in the first year.

If you are refering to the test that Finnman mentioned...
August to October is not a year.

 

[Dishmop]

I'm not sure the study proves or disproves anything except that mites can easily migrate from one colony to another.

which just about says it all.

It doesnt matter how far away the mites are.

You could irradiacate every mite within a 20 mile radius of your hives but bees from a hive outside the 20 mile limit are going to fly 3 miles into that zone, and then its like the Royal Mail service giving a parcel to the next depot for delivery to the next one.

 

[Finman]

If you are refering to the test that Finnman mentioned...
August to October is not a year.

Those things happened in NZ in few weeks and beekeepers were not able even get honey away from hives.

One of my big hives met that destiny in one month. All winter bees turned wingless mite porriage.

.

 

[domino]

If you are refering to the test that Finnman mentioned...
August to October is not a year.

I've assumed they were existing colonies given one started in August would probably die anyway. I could be wrong.

My point would be there is no benefit to misrepresenting them dying because if they all lived it wouldn't change the results.