Why Small Cell?

[Solomon]

I just wanted to write a quick set of reasoning for why we use small cell, since there is so much misinformation around, and to get this forum started.

Small cell is not a treatment, it is not something you put in a hive to reduce mite levels. In fact, we believe it may increase mite levels.

Why?

Because, I believe, it pushes the mites more toward the drone brood. We all know mites prefer drone brood, this is a scientifically proven fact and commonly accepted information. We believe smaller cells cause the mites to preferentially eat the drone brood. Drone brood is capped longer, leading to more effective reproduction of the mites.

This allows a hive to survive with a larger mite load, one perhaps beyond traditional triggers for treatment. Drones are expendable, they can be expelled from the hive with limited detriment.

Small cell will not eliminate mite problems.

Small cell will not reduce mite numbers.

We also use small cell for other various benefits, firstly because it is "more natural" than standard foundation sizes. When faced with the choice between more natural and less natural, all other factors being equal, I choose more natural. Seems like the obvious choice to me.

Smaller cells mean more brood in the same comb area. This seems self evidently a good thing, compact broodnest, easier climate control, etc.

Some evidence for quicker emergence of worker brood, possibly leading to reduced mite reproduction, leading to natural selection of mites away from eating worker brood.

Not sure if this is proven, but smaller cells may equal smaller bees which are more resource efficient to make, and have lower energy expenditure in flying.

All of this would also apply to foundationless (I do not believe "natural cell" exists in a managed hive especially starting with commercial sourced bees) providing the cell size is actually smaller than 5.2mm, which is by no means a guarantee. I have had a number of conversations where people have equivocated small cell with foundationless and then discovered their cell size was actually much larger than standard. "Small cell doesn't work, my bees died!" Unless you have small cell (4.95mm or less), you don't have small cell. And aside from that, bees still die. Fact of life.

[Neill Sayers]

I started with Russians 4 years ago and kept them in Warre hives. Sometime last year I pulled a brood comb and measured several cells just for grins with my digital calipers and they ranged between 5.0 to 5.1mm. If they continue on this track can I expect them to eventually end up at 4.9mm?

[clong]

I just wanted to write a quick set of reasoning for why we use small cell, since there is so much misinformation around, and to get this forum started.
...
Some evidence for quicker emergence of worker brood, possibly leading to reduced mite reproduction, leading to natural selection of mites away from eating worker brood.

Solomon,

Some speculation:

Samuel Ramsey's research contends that when mites are found on an adult bee, they are not truly phoretic, but are actually feeding on them. Could it be that it is harder for varroa to wedge themselves under the sternites of the small-cell worker bees? Perhaps this leads more of the varroa to gravitate to the adult drones in small-cell colonies for feeding. Has anyone ever observed mites on feeding on adult drones?

I also wonder if in addition to exponential growth, the eviction of drones in the fall may explain the rapid increase in the number of sampled varroa in colonies.

[Solomon]

Could it be that it is harder for varroa to wedge themselves under the sternites of the small-cell worker bees?

That's a good question, I don't know for sure. The mites I tend to see on my bees are generally riding on the top of the thorax, but that may just be that that's the easiest way to see them and that I'm missing other ones. But I imagine it's possible at a certain point. Are small cell bees enough smaller that it becomes a factor, I would tend to think not. They don't seem to be that much smaller physically. But this is just my pondering of the idea. I don't have any data.

Perhaps this leads more of the varroa to gravitate to the adult drones in small-cell colonies for feeding. Has anyone ever observed mites on feeding on adult drones?

I've seen plenty of mites on adult drones, newly hatched drones, in drone brood. There should be a default selection toward drone predation as drones objectively have a longer post capping time, leading to more effective reproduction of the mites. There have been studies on this, I believe. Suffice it to say for the layman, mites like drones more than workers, and we should encourage this by keeping the workers at a more natural size.

Another interesting factor, I have found drone frames, the green ones specifically, have a rather large cell size, even for drones, 7.1mm. Whereas I've polled other beekeepers and found a more natural size for drones to be in the mid sixes mm. Just measured some of my own and found 6mm to 6.4mm.

I also wonder if in addition to exponential growth, the eviction of drones in the fall may explain the rapid increase in the number of sampled varroa in colonies.

That and also the reduction in brood area.