A Much Simpler Explanation of Why Mite Bombs Happen

Some hives are bad at dealing with mites. Pretty simple huh? If mite bombs were a real thing and were as bad as purported, then a mite bomb would take down just about every hive in the vicinity. But they don't. Instead, often, the mite bomb cannot even be identified in the area, and is only assumed to exist. What does happen is this: Let's construct a hypothetical hive. This hive is bad at dealing with mites. Even though it might have been treated, it is bad at dealing with mites, so the random mite load of all the bees in the area would tend to concentrate with that hive, they don't bite mites, they don't chew them out, they basically just ignore them, and so mites build up in this hive. The hives very nearby are going to tend to receive some of this load due to drifting and robbing and if they can't deal, they'll start suffering too, but some, even many of them may be able to deal with mites, or even deal with them well. So these don't suffer, even with an increased incoming mite load. Hives that are very mite tolerant or resistant will absorb this load and eliminate the mites, becoming what we call "mite black holes." They suck in mites, never to be seen again. But in the mite bomb hives, generally sourced from non-resistant or tolerant commercial stock, the mite load increases to damaging proportions and they collapse, forming a "mite bomb" or maybe a "mite big bang?" These hives, it seems, do increase the mite load around, but again, it is the responsibility of the nearby hives to deal with their own mite loads. Those of us who are in the habit of catching swarms will have these mite bangs most years. And we have been told many times about these mite bombs, but yet, they don't seem to do much if any damage to the surrounding hives. Mite bombs never seem to knock out whole yards. They haven't knocked out any of mine. When I catch a good batch of swarms, I start a new yard with them, so they're all in the same spot for the first year. Inevitably, around a third of the fresh swarms will die, mite collapse, yet the rest in the yard don't seem to suffer. From the early days of this "mite bomb" idea, I have never warmed to it. It just doesn't seem to fit what I've seen and doesn't seem to fit the data of the people around me. I know a good number of people who catch a lot of swarms and bring them home and some of them have mite collapses, and none of them seem to lose many, if any hives, to mites caused by mite bombs of the hives next door. So I conclude that mite bombs are just hives that don't deal with mites well and collapse. And any hive in the vicinity that also collapses is also a hive that doesn't deal with mites well. These are hives that in the final analysis need to be eliminated one way or another. What better test than real world conditions?

Drones (the case that drones are not PALTs)

Unlike what you may have been taught, drones are not just partially autonomous loafing testicles (PALTs) hanging around the hive eating up honey and being a drain on the colony. They are actually useful and cultivating a natural amount of drone comb is good for the hive, especially the treatment free hobbyist's hive.

One of the major benefits for the TF hive is that drones are a sink for varroa. Varroa are naturally drawn to the larger meatier drones with their longer development times. If the bees can successfully keep varroa in the drone brood (through smaller worker cells) then the damage the varroa do is confined to the drones. Damaged drones are then removed and ejected from the hive, costing little more than the bit of pollen and honey it took to make them, but saving a worker who would have cost not only the construction materials, but also the loss of a worker to do the work. I have seen hives that didn't have much hygienic ability but because they were confining the varroa to the drone brood, were able to successfully maintain operations with a relatively high mite load.

Secondly, I see drones as very useful for influencing the surrounding genetics to your location. It has been said that drones raised in more naturally sized cell hives fly faster and are healthier than extra large treated drones. That means your drones can have a much better chance of getting out there and mating with new queens in your area, and if your drones are TF survivors, you are pulling up the genetics in your area to match yours. That means even treated hives that swarm (or supersede their queen, which they often do) can have a measure of TF survivor genetics which in turn can re-benefit your operation when your queens mate.

As far as the food drones are supposed to be eating, bees eat relatively little. We all know that a single worker will only bring in about 1/20 of the teaspoon of honey (about one worker cell volume) in its lifetime, but may bring in sixty times that much weight (40 times the volume) in pollen. All the drones produced in a hive in a year may cost the hive only a couple pounds of honey and a couple pounds of pollen. Many times that are spent making workers. So do we reduce the number of workers? Of course not. It does cost the hive to make drones, I estimate it takes the honey production of one or two workers to make each drone. But if that drone prevents a varroa from infesting a worker, then you have pretty much made that worker-equivalent back. And how valuable is having a good drone to mate with your virgin queen? And let's remember that there are 4-9 times as many workers as there are drones, even in the worst of times. And the workers know how many drones to make, don't forget that.

Fourth, numbers from the Bee Informed National Survey show that removing drone brood does little to nothing for the survival of the colony, ostensibly due to varroa. You may be removing some varroa, but then the rest are going to have nowhere else to go but into worker brood, further damaging your hive's ability to deal with varroa and in fact selecting for varroa that infest worker brood, which we absolutely don't want. Every action we take in the hive selects for something. We are TF because we want strong bees and weak mites. Let's not muddy the waters by selecting for mites that like worker brood, that only hurts us.

In conclusion, I would say that you're not helping yourself all that much by getting rid of drones or drone brood, and in fact, the bees are going to want to build that drone brood back anyway, so you've perhaps cost yourself time and energy to build that comb again. You are hurting yourself by removing drones due to the selection of worker brood infesting mites, limiting your beneficial effect on the surrounding colonies, and by not sacrificing those drones to the mites which will protect your workers.

Survey of Mites in Capped Brood Cells

So I was out working the bees today and I was removing some deep frames from a medium hive.  The bees had built comb hanging from the bottom of the frames.  It was the only way I had to get a deep nuc into a medium hive last year.

I took the best of the brood comb and tied it into a foundationless frame:

However, a lot of the comb was drone and so out of curiousity I started pulling out the drone brood and counting and separating them by which ones had mites and which didn't.  Then out of more curiosity, I did the same with the last little bit of worker brood there was on a similar piece of comb. 

Here are the results:  Of the drone brood, I uncapped 56 drones, finding 15/56 (27%) infested with at least one varroa, and two with two mites for a total of 17 mites.  Of the worker brood, I uncapped 73 and found 5 infested with a mite (7%) and one having successfully reproduced, showing multiple mites in the cell, in the typical ages of a mite lifecycle in a honeybee cell (1.4%).  I did not find any reproducing mites in the drone cells, but as you can see in the picture above, the drones were all recently capped whereas many of the workers were near emergence.

What does this demonstrate?

First, I have mites.  No surprise there, I have been saying that for years.

Second, I have plenty of mites.  No tiny insignificant population here.  This is not a hive that has demonstrated hygienic traits, yet survives nonetheless.

Third, the mites obviously prefer the drone brood, infesting at a rate of one in four while worker brood was only infested at a rate of one in fourteen.

Fourth, some hives are capable of handling a substantial mite load without crashing or even showing detrimental effects.  This hive is about the fourth strongest in this yard of nine.  I used it as my cell builder this year.

Five, if these numbers hold out, mites are not terribly successful at reproducing in worker brood in this hive, only about 1 in 71 worker cells result in mite reproduction.

And for some background data, I measured the cell size of this piece of nearly perfect free form comb and found the cell size to be a consistent 5.2mm.  The rest of the comb in the hive is 4.9mm wax or 4.95mm plastic.

How Many Mites?

Here is a picture of the bottom board of a hive I took apart on Saturday.

If you right click and select 'View Image' you may be able to see the number of mites there are on this bottom board.  There are tons, hundreds, maybe as many as a thousand.  This is what I would expect to see on a bottom board from a hive that had died from varroa mites.

But this hive not dead.

This is the hive that I expected to die last fall due to an extremely high mite load.  I remember inspecting this hive and seeing mites everywhere.  I saw them crawling on bees, in cells with brood, crawling across the comb, everywhere.  There were hundreds.

I expected this hive to die.  But it didn't.  Remember, this is a completely treatment free hive.  No treatments ever.  And yet it survives, even with a massive mite load.  Admittedly, it's not doing great, but we shall see what happens.  This is one of the reasons I let hives die on their own, to see exactly how much they can take and if they have what it takes to survive.

First Deadout of Winter

Here's today's yard.

 Sad news, today I discovered my first deadout of the winter.  I've gotten better at knowing a deadout without even looking inside.  Bees will be coming and going, but they will be acting more like robbers and in this case, they will be trying to use the lower entrance which this hive never took to.  Around here, dead hives not uncommon for this time of the year, but the reason varies.  Let's look at some of the signs.  What's left of the hive (all the uncapped honey) is located in the back middle of this picture.  I figure any hive able to be out flying through the winter can have all the honey they can carry home.  The hives headed by the queens I ordered from Zia seem do be flying just fine in 45 degree temperatures.

The first thing I found was this in the second box from the bottom.

At first, I thought the hive was queenless because the queen wasn't in this cluster.  There was a hive beetle though.  There was also plenty of honey around the cluster, though it was uncapped.

As I began to take the hive apart and take stock, I found this right at the top of the hive right under the sugar.  Like the lower cluster, they were surrounded by uncapped honey and you can see in this picture just how close it was.  They also had a very healthy supply of pollen.

There the queen is.  She looks like a standard Italian if not just a little dark complected.  This hive was a swarm I caught last spring, and I saw old used queen cells in the hive so I assume this is not the queen that swarmed with the hive.

I also took a good hard look at the bottom board.  That's one of the most important things to look at.  There were about half a dozen beetles and about two dozen mites.  Neither of these things is likely the source of the demise of this hive.  There were dead bees, but not enough to form a solid layer across the bottom.

The primary issue with this hive seems to me to be a divided cluster.  But the question must be asked as to why their population is so low.  I checked my records and this hive was designated SW-NWA-0000-0004 meaning that it was a swarm from around here with unknown parentage.  This hive mysteriously showed up clustered under my comb melting vat last year.  It made it through last year well enough, but had a tough start this spring taking heavy damage from skunk predation.  This apparently triggered a supersedure this spring.  Later on, the hive was healthy enough to harvest three frames of honey from to supply some new nucs.  This hive did show some minor signs of dysentery this spring, but every thing cleared up.  By fall inspection time, they were just about the least provisioned of any of the hives and I put a top feeder on.  They did not take much syrup, and I found what they did take (it was dyed) on one of the combs.  Most of what they had was real honey.

I did my best, but this hive was never a performer.  Perhaps in the future, a hive like this will be placed in a nuc or combined with another hive so that it won't be taking up valuable equipment.  However, at this point, I have plenty of equipment so it's not really an issue.  They ended up being comb babysitters more than anything.  So far, survivors are 10 of 11.  Let's hope there will be very few more deadouts.  It's another big splitting year next year.