. Wouldn't this have a negative effect in winter..
Or actually the opposite - it has a postiive effect. By allowing the moisture out , it provides a healthier environment for the bees. It is damp not cold that kills most colonies.
I overwinter all my bees on mesh floors. They all survived bar the little one which was poor all last summer/autumn.
It's important to close off any top ventalation (in the UK at least) as you don't want a chimney effect of warm air rising up out the colony. Warm air rises and is trapped at the top of the hive.
Our National Bee Unit is recommending all bee keepers switch to these open mesh floors, and this information is being disseminated via the local bee inpsectors.
It is especially good when applying varroa treatments, as partially resistant mites, which may be knocked off, recover and climb back up, fall through the mesh and do not return.
As many as 20 - 30% of mites are thought to "drop off" in any period, and if they can't climb back up - thats a significant bio-friendly method.
I have suffered no effects as a result of using mesh floors, and as they can ventilate through the bottom to drive of moisture in the summer, you can keep the enterances narrow at all times, - I never ever remove my entrance restrictors. Hence I seem to be the only beekeeper I know who didn't suffer any losses due to wasps at all this summer. Perhaps having them in place all through the season helps. Maybe wasps start sneaking in earlier in the season than we think - and hence learn to come back once their protien source dries up. Anyway, I had no problems with wasps at all.
It's also easier to smoke, - just a few puffs under the hive is all thats required, - it evenly wafts up through the frames.
Light is not an issue - just look at a ferral colony which builds on a tree branch.
I do however stick a 2 inch thick piece of polystyrene over treh hive roof in winter - to keep the frost off the roof - even through the underneath is completely open.
All my hives have come through strong - a sign of the benefits perhaps?
I've never seen "damp" comb since I started using them - just in other peoples hives these days!
Hope thats of help.