What do you think happens in the fall with Varroa?

[Michael Bush]

I would love to hear other peoples view of why there are sudden increases in population in the fall and the ramifications for various treatments/methods.

IÂ’m not sure what it is that happens sometimes when the population of Varroa explodes. If it happens, it almost always happens around here (Southeast Nebraska) in about September or so. Some years it doesnÂ’t happen at all, but some years the population of mites goes from a natural drop of 6 or 7 mites in 24 hours to thousands. This phenomena is intriguing to me and the only explanation I can see for it is mites coming in as hitchhikers from other hives that are crashing and being robbed by my bees. Certainly SOME of the mites are coming from emerging bees and there is no where for them to get back in a cell so the population of mites on the bees seems to go up because they canÂ’t get back in a cell, but I donÂ’t think itÂ’s an adequate explanation for the exponential increase in mite numbers. Does anyone have another theory?

Without getting into the issue of what methods are best, I think itÂ’s significant to the success and sometimes subsequent failure of many of the methods we, as beekeepers are trying to use. As an example, I had hives that had been treated with FGMO fog only for two years and when I killed all of the mites with Oxalic acid at the end of that two years there was a total mite load of an average of about 200 mites per hive. This is a very low mite count. But some people have observed a sudden increase to thousands and thousands of mites in a short time. I believe the issue is that the FGMO (and many other systems as well) manage to create a stable population of mites within the hive, either by killing portion of the mites, or by preventing their reproduction. In other words the mites emerging is balanced out by the mites dying, either by killing some of them to make the balance or by suppresing reproduction. This is the object of many methods. SMR queens are queens that reduce the mitesÂ’ ability to reproduce. Small cell reduces the mites' ability to reproduce. Hygenic bees clean out infested brood. But even if you get to a stable reproduction of mites, this does not preclude thousands of hitchhikers coming in. Using powdered sugar, small cell, FGMO or whatever that gives an edge to the bees by dislodging a proportion of the mites, or preventing the reproduction of mites and seems to work under some conditions. I believe these conditions are where there are not a significant number of mites coming into the hive from other sources.

All of these methods seem to fail sometimes when there is a sudden increase in mites in the fall.

Then there are other methods that are more brute force. In other words they kill virtually all the mites. Even these seem to fail sometimes. We have assumed itÂ’s because of resistance, and perhaps this is a contributing factor. But what if sometimes itÂ’s again because of this huge influx of mites from outside the hive? Granted having the poison in the hive over a period of time when this explosion of population occurs seems to be helpful, in some ways, but it still sometimes fails.

IÂ’d love to hear other peoplesÂ’ observations and theories on this.

And, since I'm sure Jim Fischer will jump on this like a duck on a junebug and acuse me of contradicting myself somehow because I'm not religious enough in my belief in small cell, no, I have not had this happen on small cell... yet. Nor have I had it happen on FGMO. I have seen it happen when I was using Apistan. But others have observed it with FGMO and I have to wonder how much this affects the success of many methods from Sucracide to SMR queens, from FGMO to Small Cell.

It seems like there are at least two components to success with Varroa mites. The first is to create a stable system so that the mite population is not increasing within the hive. The second is to find a way to monitor and recover from that occasional sudden influx of mites.

So, everyone, what are your thoughts and observations? Does anyone have another explantion for population explosions of the Varroa?

[loggermike]

Nothing to add really.Any time of the season there is a dearth bees will rob any vulnerable hives .We have all seen hives that are crashing getting robbed out and thats one reason mites spread rapidly.(here is where last years swarms come back to haunt you)No mystery there.The only other reason for the 'sudden buildup' is that the mites werent knocked back by whatever the last treatment was and have been quietly and rapidly increasing.Its either natural reproduction or reinfestation,what else could it be?

[Michael Bush]

>what else could it be?

I guess that's the reason I lean toward the hitchikers. Especially when mite populations have been stable and there is a sudden huge change. I don't see where else they can come from but even then it seems like there are too many to account for. But maybe more of them can hitchike that I am imagining.

[loggermike]

I am leaning towards that too.If a crashing hive has 5 to 10000 mites and is being robbed by several hives with the mites jumping on the robbers (rats abandoning a sinking ship)then the robbing hives CAN get a huge influx.Usually many hives are involved in the robbing but this can be going on in a large area with many hives involved ,especially if there are lots of hives in the area with chemical resistant mites.Your problem becomes my problem,mine becomes his,his becomes........etc.Ineffective treatments are a real danger to everyones hives.

[BULLSEYE BILL]

>Then there are other methods that are more brute force. In other words they kill virtually all the mites. Even these seem to fail sometimes. We have assumed itÂ’s because of resistance, and perhaps this is a contributing factor.

I am curious about the claimed resistance from chemicals. Have assumed resistant mites been examimed in a laboratory? Have they been subjected to the actual chems to see first hand that they are resistant?

I ask because it occures to me that if a hive is treated with Apistan and afterwards it still has mites, were the mites really subjected to the Apistan or were they late arrivals that hitchiked in? Thus presumeing that they were resistant when in fact they may have not been exposed?

[?honey?]

I have a lot to learn from this post but nothing to add. I will be reading regularily. This will notify me when someone posts a reply.

[loggermike]

I have also wondered if some who claim chemical resistance didnt put it on too late-after the mites had already done too much damage to save the hive.

[Michael Bush]

>I ask because it occures to me that if a hive is treated with Apistan and afterwards it still has mites, were the mites really subjected to the Apistan or were they late arrivals that hitchiked in? Thus presumeing that they were resistant when in fact they may have not been exposed?

That was one thing I was wondering. Maybe they put the chemicals on too soon and missed killing the influx of hitchikers.


>I have also wondered if some who claim chemical resistance didnt put it on too late-after the mites had already done too much damage to save the hive.

There is another issue. Maybe they were too late to avoid the damage.

Because the large explosion of population seems to happen all of a sudden how much effect does it have WHEN that happens. Maybe it happens when there is a dearth and a weak hive gets robbed in the Summer or maybe it happens as Fall comes in. But a combination of that, when the mite population goes through that explosion, and when they were treated might be a big part of sucess or failure of any given method.

[jfischer]

> And, since I'm sure Jim Fischer will
> jump on this like a duck on a junebug
> and acuse me of contradicting myself...

You apparently have me confused with
George W. Bush and Dick Cheney. THEY are
the experts at accusing people of contradicting
themselves.

And its not really fair to get angry at me for
something before I even THINK about doing it. http://www.beesource.com/ubb/smile.gif

The whole "fall mite thing" has to be prefaced
with an understanding that it takes weeks and
weeks for any but an overwhelming population of
mites to cause colony collapse, and there is
no way that such a large number of mites are
going to wander in on drifting bees.

Wyatt Mangum (who often writes for ABJ) has done
quite a bit of work in this specific area, and
his view in the reinfestation by isolated
drifting bees is happening all the time. He's
got a few hundred hives worth of weekly mite-drop
data over at least two years to back up his
view, which may be the largest sample set ever
monitored.

So, if your hive crashes in fall, it was infested
in mid-summer. If you treated only weeks before,
either your treatment was ineffective, or was not
done often enough to "knock down" the varroa
population sufficiently to prevent the collapse.

Wyatt's data may show the specific population growth
in reinfested hives, but I don't have it handy.
Regardless, everyone's data shows that it takes weeks
and weeks to go from "reinfested" to "colony collapse".

[Michael Bush]

I agree it seems to take weeks to the actual collapse. But it does not seem to take a very long time of the mite population to explode. That population explosions is what I find hard to explain.

[loggermike]

I think the varroa population increase is like compounding interest-it starts out small then suddenly you're in BK court!

[BjornBee]

I would like to add that the assumption that chemicals kill all the mites is wrong. There is always mites not killed. This is for resistant reasons or not coming into contact with enough chemicals to cause death. There will always be a few left that has come into contact with some level of the chemicals and may over time, become resistant. This is why resistance develops. Again, no chemical treatment is 100%. The chem makers do not make this claim. Rotating chemicals from year to year at least will ensure that the highest kill rate can be achieved from treatments.

The increase in mite levels is a combination of several things.

Robbing from dying hives.

The expulsion of drones. If you do the math for the population of drones, and add them to workers in the fall, the percentages can be effected drastically.

The peak population of bees going down in the range of 10,000 to 20,000 bees at this time of year Do the math....

The eliminating of brood/bee areas as beekeepers eliminate supers and other hive areas in preparation for winter. This compresses the bees into a smaller area, and can effect the exchange/transmission/ and breeding patterns for mites. Actually may increase mites per cell as bees are compressed.

Natural bee cluster activity at night (when cold)will add to the level of mites in a particular area of the hive. This may help the efficiency of mites ability to breed at higher levels. In summer bees are more spread out throughout the hive. There is only a small window of opportunity for mites to enter a cell before capping. More bees in the brood chamber...more mites(per area)....more success in finding a cell.

Continual feeding by beekeepers do not allow a natural brood cycle to stop. This "normally" happens in most area, but beekeepers are good at feeding. This may continue or at least help the mites with an uninterrupted brood laying period.

Most beekeepers know that mite levels will gradually rise and will peak with devestating results. Most medicate too late, after the level is beyond help.

If your looking for a 100% answer, I feel the only way to get it is to add up all the nickels. Its alot of little things that make the big picture and not one item that can answer it all.

I will also like to add that chemical resistance in nearly all cases stem from two things. Beekeepers leaving the strips on all winter and not removing them as dirceted. And the use of the same chemical year after year.

Doing a pettis test every year will determine if your bees are resistant and will direct you to which chemical strip has a more effective kill rate for your mites. (which may of come from someone elses hives)

Monitoring mite levels to determine if steps are needed is usually not completed by most beekeepers.

[Dave W]

Greetings . . .

Been reading my "new" book, MITES OF THE HONEY BEE.

To add to the thought about "exploding population", the above book declares;
1) on average, mites reproduce at a rate of 1 or 2 mites per female
2) only approx 100 mites per day are returned to hive by robbers

Using THIS info, I cant understand the "explosion" but,

If 50,000 bees are infested (carring) w/ mites, and 4, 5, or 6 frames of brood w/ each cell infested w/ 1, 2, 3, 4 mites, and colony begins to "downsize" for winter (fewer host bees and a lot less brood) where do all the mite go?

Population does not "exploded", its just concentrated in a "smaller space".

DISCLAIMER http://www.beesource.com/ubb/smile.gif None of above may be true, Im just a newbee w/ a lot of mites too!

------------------
Dave W . . .

Hobbyist - 1 Hive
First Package - Apr 03
Broodnest - 3 Deeps
Screened Bottom Board
Apistan - Aug 18, 03
Grease Patties - All year
2003/04 Winter Loss - 0%
See Forum1/HTML/001304, for ongoing mite counts.

[shoefly]

Caveat, I'm new to this - no mentionable long-term experience with the beekeeping just thinking.

What if the mite populations are always exploding but some environmental factor keeps them in check - except for certain conditions in September? The success or failure of mite brood-cycle seems to depend in part on the length of the bee brood-cycle.
The shorter length of the bee brood-cycle may be one reason why small cell bees (an old bee keeper friend calls them "Mickey Mouse bees") are more successful in raising fewer mites. The brood cycle for small cell bees is shorter - too short for the full development of most mites. If there is an environmental condition (temperature?) that slightly lengthens the bee brood cycle the mite brood cycle could benefit and many more mites successfully mature - alas an explosion!

From the mites vantage point it would make a lot more sense to hitch a ride on a robber than to jump onto bees of a crashing hive. The ensuing unprotected frost dooms the mites as well, wouldn't it?

...and then there are the drones. Mites love to develop in drone cells. Isn't it because the drones take longer to develop? In the fall though it would make sense for the mites to jump off the drones before they get the boot.

[Michael Bush]

>What if the mite populations are always exploding but some environmental factor keeps them in check - except for certain conditions in September?

That would be a reasonable explanation. But we still need a mechanism.

>The success or failure of mite brood-cycle seems to depend in part on the length of the bee brood-cycle.

Certainly.

>The shorter length of the bee brood-cycle may be one reason why small cell bees (an old bee keeper friend calls them "Mickey Mouse bees") are more successful in raising fewer mites.

That has been my observation.

>The brood cycle for small cell bees is shorter - too short for the full development of most mites.

One day less pre capping one day less post capping.

>If there is an environmental condition (temperature?) that slightly lengthens the bee brood cycle the mite brood cycle could benefit and many more mites successfully mature - alas an explosion!

If the brood cycle were lengthened by one full day it would almost double the number of mites reproducing.

>From the mites vantage point it would make a lot more sense to hitch a ride on a robber than to jump onto bees of a crashing hive.

But how would they sense a robber vs a crashing hive occupant?

>The ensuing unprotected frost dooms the mites as well, wouldn't it?

When the bees die, the mites die. Frost or no.

>...and then there are the drones. Mites love to develop in drone cells. Isn't it because the drones take longer to develop?

That is exactly why they reproduce better in drones and is supsected to be why the prefer them.

>In the fall though it would make sense for the mites to jump off the drones before they get the boot.

Yes it would. But do they?

[loggermike]

We dont know why mites do what they do.I have heard of research being done to find what stimulates the mite to go into a brood cell.If it is a specific pheremone or odor then we could design a trap that draws the mites to a concentrate of that odor.Thats why basic research is so important-let the scientists figure out why and WE will figure out how to use that info.

[jfischer]

>> I agree it seems to take weeks to the actual collapse.
>> But it does not seem to take a very long time of the mite
>> population to explode. That population explosions is what
>> I find hard to explain.

Well, the mite reproduction rate is limited by the 21 day
capping and development cycle for egg-larvae-bee, so it
would be impossible for the varroa population to "explode"
any faster.

> I think the varroa population increase is like compounding
> interest-it starts out small then suddenly you're in BK court!

This is true. It takes time for varroa to overwhelm a colony,
and if left undetected, it certainly CAN seem like a "sudden
explosion".

[loggermike]

When varroa first arrived here ,an Austrian wrote some very informative articles in the ABJ on what we could expect.One of his statements was that you could expect a monthly doubling in mite population.An example:Say you treated with Apistan in September of last year.There were roughly 3000 mites when you treated.The strips worked well and 98% of the mites were killed.So 60 were still alive but un-noticed.The bees began rearing brood substantilly in mid -feb. so a monthly doubling would go:March 120,
April 240,May,480,June 960,July 1920,August3840,Sept 7680,Oct.(deadout).Of course there are too many variables for this to be an absolute formula,but it does give an idea of why varroa seems to explode in late summer.

[Hillbillynursery]

I think it was MB that mentioned spreading the bees out farther(long hive) over a screened bottom board would in theory keep so many mites from falling and getting on another bee before hitting the screened bottom board. In theory it sounds viable. The theory was if you streched the hive thin enough over a screened bottom board you could get rid of nearly all mites. The problem is proving these theories. And will the bees work under these conditions.

About the doubling theory, it makes sence. If take into account the screen bottom boards many of us use then you see why removing one mite is so important. If you start with 59 in Feb, in Sept. you get 7552 which is 128 less mites. That is from removing one mite in Feb. If you remove one per hundred each month, you end up with 7144 that is 536 roughly less mites. It really makes you think about how removing just a few makes a big difference. If you add in small cell to slow reproduction and hygenic behavior and grooming behavior you can see how easy it woud be to get bees that can live with mites as they would keep mite levels low. This would take all beekeepers to work toward this goal to get there in a timely manner.