It does two really great things. First it helps the hive to receive better airflow in the summer when it's hot and the bees spend a lot of energy just trying to keep the hive cool enough. But Secondly it helps keep the varroa mite levels down in a super-easy chemical-free beekeeping strategy.
The mites reproduce by laying eggs on a honeybee larva. When the larva emerges from its cell so do the new mites. Very frequently they fall the the bottom board and then crawl back up finding a bee to latch on to. With a screened bottom, you have a large number of mites that simply fall through the screen to the ground and they are not able to find their way back into the colony to terrorize it.
|This is how I honeybee-- rubber kitchen gloves and a mosquito net from the Target dollar spot. Classy!|
|Dust sifting through the hen's feathers as she walks away.|
So in caring for our bees against this modern plague, we look to long-standing natural methods for integrated pest management (aka: a number of complimentary methods), to help keep the pest levels down in our colony. It's exciting that our colony has survived through three winters already and we've never had to use any chemical control in our hive.
I don't know what we will do with our hive when we move. The crazy part of me wants to take them with us!
But maybe it would be ok to sell them--I'm interested to try some additional beekeeping methods such as natural-sized cells and top bar hives like the warre hive, which encourage strong hives without chemical management as well.