Theory About Upper Entrance in Winter

[c10250]

OK, bear with me here. I have been keeping bees for three years now and have yet to lose a hive over winter (Chicago Area). I always insulate and run with an upper and lower entrance (reduced). Last year one of my hives went through around 30 lbs of stores from October until March. I thought that was real good until Finski (the Finish beekeper on this forum) basically called my bees pigs. He thought that 30 lbs was a very large amount of stores to go through. Many on this forum and others said that running an upper entrance causes them to burn through much more stores than they normally would.

Now, most of us know that an upper entrance is used to prevent condensation over the bees in the winter. A hive in the winter is a very humid environment. Without an upper entrance, hot humid air created by the bees would rise, hit the top of the hive, condense, and drip on the bees, killing them. However, if you have the most insulation over head then condensation over the bees would be practically impossible, instead condensing on cooler surfaces (the sides or bottom). So, if you throw a bunch of insulation over top of the bees, why have an upper entrance?

I have been thinking of this for some time and was on the fence. I mean, how can you argue with my success for overwintering? Why change? I think I'm going to change though. The tipping point came with this month's beeculture and ABJ. In this month's CAP article, they discussed varroa mite biology. There was a section on humidity in the hive which stated that varroa hate humidity. The higher the humidity in the hive, the less varroa are able to reproduce. The section concluded with the following statement, "[i]f there are ways to artificially increase the [relative himidity] to about 80%, then the varroa mite population will never increase to a damaging level." Whoa!

We all know that hives are incredably humid during the winter, and most of us do everything we can do to reduce this. It now occurs to me that we might actually be helping out the varroa when doing this. So, I'm going to give the "no upper entrance" thing a try. Insulating heavily over the top of the bees is a must.

Thoughts?

Ken

[Hawkster]

since there is little to no brood in the winter time, and humidity seems to inhibit their ability to reproduce i am not sure what you gain ? making it hard for them to reproduce when they aren't reproducing anyway ? what am i missing

[c10250]

Bees do reproduce in the winter. Not in such numbers as the summer. They do start reproducing again in larger numbers in late winter.

The low number of brood in early winter is one reason why a high mite load going into winter is a bad thing. You wind up with few brood and many mites. That is why I treat in the fall. So after treating in the fall, you wind up with a lot fewer mites, however, you have a lot fewer brood. The mites can still do damage because the mite to brood ratio is still up there.

Now, if you prevent the mites from reproducing in winter (especially late winter after the queen picks up), after your fall treatment, you might start the spring with a much lower mite load. . . ???

[Barry]

The only thought I have is to share my experience, living in the same area. Never wrap or insulate and no upper hole or ventilation. Just a 3/8" opening about 8 inches wide. Keeping bees 15 years this way and don't have dead bees in spring either. In the spring I remove the propolis around the inner cover hole between the outer cover. In the fall the bees seal it shut. I figure they know how they like it.

[jmgi]

Generally speaking, there is no brood rearing in the winter where I live, I don't know about where you are, therefore mite reproduction in the winter is a non-issue for me. John

[c10250]

I am quite sure that in most northern areas there is little brood in November, December and most of January, however in late January in N. IL, your queen will start laying in ernest. By Febuary and March you will have lots of brood for the spring build up. . . . lots. By March I had 9 frames of bees last year. The hive was packed. That means a lot of brood in January and Febuary. If you could keep the humidity up by having no upper entrance, there would be no increase in mites.

[Ian]

Its a bit colder up here, and we tend to get alot of snow, so the upper entrance tends to be more important here. The bees tend to propolize them shut up here also but they probably do not realize they are nesting on the ground, where their entrance gets snowed and iced shut. They will primarily use the upper entrance late winter and well into spring

[Barry]

That's the one thing I have to keep on top of is making sure they don't get snowed in. I may try closing up the bottom for winters and only keep an upper. Haven't had time to play around with this yet.

[Adrian Quiney WI]

Ken, I think the insulation/ventilation debate is eternally confusing. My suggestion would be try 1/2 your bees the new way and half your old way and see the results. What would you take as a measure of success? Would it be survival, or survival with lower mite counts?

[psfred]

The amount of ventilation is better controlled by restricting the lower entrance I think -- you want plenty of oxygen in the hive, but you don't want to have water condensing on the top over the cluster and dripping on them. Lots of ways to prevent this, including insulation, Warre quilts and "condensers (shavings boxes), candy boards, and nothing.

I plan to leave an upper entrance (the notch in the inner cover) about an inch or inch and a half wide and between 1/4 and 3/8" deep. My bees seem to like using it in the spring, and it allows enough air flow to get rid of excess moisture but not enough to freeze the bees.

I am using only wooden covers from now on out, had too much water dripping on the inner cover with a plastic one.

Peter

[Harley Craig]

could you just tilt the hive a few degrees ? theoretically any condensation should run to the edge and down instead of dripping on the bees.

[MattDavey]

I have a long hive (double width) with top entrances (either end), the cluster was in the centre. The top of the hive was dry, but the outer bottom edges were damp from condensation. The inside of the outer walls and the frames closest to the wall also had mildew on them. Mostly towards the bottom half.

Matthew Davey

[Acebird]

I think lower entrance hives were developed for the beekeeper and upper entrance hives benefits the bees. Bees will survive in both because they are adaptive. Which one is altimetly better for survival will be hard to get numbers on because most hives are bottom entrance hives.

[heus]

I purchased Honey Run Apaiaries' all-season ventilated/insulated tops with an upper entrance for my hives. This will be my first winter with bees. Not sure if I am going to wrap or not.

[libhart]

I also read the report about humidity affecting varroa and thought about ways to do this for about 3 minutes until I realized what 80%RH would do to hygroscopic honey at which point I stopped thinking about it.

[AR Beekeeper]

Elbert Jaycox overwintered colonies at the University of Illinois using bottom entrances only, without any ventilation above. The entrances were open full width and were 3/8 inch high. He had no problems with moisture dripping on the bees. He also recommended that bottom entrances be fully closed if upper entrances were used.

[jmgi]

Elbert Jaycox, now there's a name I don't hear too often, I have a book of his in my library. Anyway, I assume he didn't like both a bottom and top entrance because it would cause too much cross ventilation in winter. I know that full open bottom entrances used to be the thing to do many years ago when I started out and upper entrances were hardly ever used from what I recall. John

[Oldtimer]

I don't use top entrances, other than to choc the boxes a bit on really strong hives in summer.

But C10250, I don't think a beekeeper from another country, using different bees, in a different climate, can tell you your bees are eating too much. In fact, just that they assume they can, shows a lack of understanding on their part.

Generally I would consider 30 lbs for winter not too bad, but it depends how you define winter. Is any brood raising period included? If we are talking carniolan bees, through their broodless period only, food consumption would be much lower than 30 lbs. But if we define winter as the period from when they are prepared by us for winter, until the first spring nectar starts coming in, so they have already been raising brood for quite a time before nectar starts, and they are italian bees, food consumption could be well over 30 lbs.

There is anecdotal evidence that bees on mesh bottom boards consume more honey in winter than bees on solid bottom boards, presumably needing more fuel to keep warm. So if a top entrance causes more cold air to circulate, that could have the same effect. Would it reduce condensation? I don't think that's been proved at this time.

[Acebird]

Do you think a colony will raise brood if they are short on stores for the winter? I think if the stores are plentiful in the spring or late winter the colony goes gang busters to expand and if they are short on stores they will conserve. I realize I don't have a lot of experience but I am confident that a surplus of honey allowed my one surviving hive to really take off last spring.

[Baja]

The 2011 Bee Informed Survey on Winter Preparation (http://beeinformed.org/2012/03/bee-i...vey-2010-2011/) with Dennis vanEngelsdorp showed slightly reduced losses from beekeepers who used insulation wrap, lid insulation, mouse guard and tar paper wrap but significant benefits came from beekeepers who equalized their hives and for those who had an upper entrance (https://www.box.com/s/2u7fv32euq6h7ksgpdyo). I personally do all of the above as well as an insulated moisture quilt to absorb moisture. When you say upper entrance do you mean a full upper entrance or an inner cover entrance?