The most important thing about a top bar hive - is what goes on inside....
When I am asked to speak to groups about top bar hives - I like to start out with the one most important take-away point, "rendered," if you will, into one concise statement:
"It's All About the Wax!"
What do I mean by that? I mean that natural beeswax comb - made BY bees, FOR bees - is clean, it's the correct shape, and the cells are the right size for what the bees know they need.
So the best way to support the natural systems at work inside a beehive - is to simply let the bees be in charge of building their combs.
The use of wax foundation was a great convenience for the beekeeper when it came into use back in the 1800's. It caused the bees to make razor-straight comb, which sped things up for the beekeeper. Now inspections took less time; honey extraction could be mechanized; beekeepers could manage more hives. Beekeeping was on its way to becoming a business!
Foundation also dictated the size of the hexagons in the comb. This effect was obvious and beekeepers utilized it happily: the size of the cell determines the gender of the baby bee raised in it. Hallelujah! We can make a hive of all girls! And since girl bees "do all the work" - gathering nectar, turning it into honey, raising baby bees, collecting pollen, building wax - who wants those boy bees around anyway? And... genetic diversity? Hmmm...
Other trickle-down effects from foundation were slower to come to the surface. Cells in foundation were made slightly larger than the bees made in natural wax combs - affecting the length of the gestation cycle of the bee. Bigger bees took longer to develop. This may have never been an issue had we not encountered the varroa mite in the mid-1980's. The longer the gestation cycle of the bees, the better that supports the varroa mite's reproductive requirements. Ack! More mites?!
And when we found ourselves dealing with the varroa mite, we went after them with gusto - using some seriously toxic chemicals in our attempts to eradicate them. That's when we realized that those chemicals were "lipophilic" - and had been absorbed into the bees' wax combs. After years of chemical treatments, we have managed to contaminate the wax supply from which foundation is made - making even brand new foundation full of chemical contamination. Not an auspicious start for a new beehive.
Natural beeswax combs are the heart and skeleton of any beehive. Simply letting the bees make their own wax - to their own specifications - can overcome a whole lot of the "help" that we humans, with our big brains and our opposable thumbs, have inflicted upon the bees.
Because for the bees - "It's All About the Wax!"