Strange Bee Behavior-Screened Bottom Boards?

[Jacobs]

At our September GCBA meeting we asked Don Hopkins about large numbers of bees gathering under the bottom board of hives and the response was that bees were doing strange things this year. I had two hives with screened bottom boards have the same thing happen this season.

About 3 weeks ago I went through the hive with the largest number of bees underneath. I went through every frame and saw no eggs, larvae or brood, but the bees were calm. There appeared to be as many bees clustered under the screened bottom board as were in the hive, and the inside of the bottom board was covered in live bees, obviously in contact with the outside bees. After taking a small scoop of underneath bees and seeing they did not fight when placed on the landing board, I set aside the deep and first medium and dumped the bottom board bees onto the top of the second medium. The bees covered the top of the medium and started going in. I left it for about 5 minutes and watched other bees walking toward that medium and going in. I reassembled the hive and left it for a week.

On inspection I saw a nice pattern of newly laid eggs in the first medium above the deep and I closed the hive up. Only a few bees are now under the bottom board. I have not used the plastic insert to close the hive bottom, but I have on all of my other screened bottom hives. I will have to slide them open every couple of weeks to clean out wax, droppings, etc., but I am inclined to leave them on more or less permanently.

In my hives with screened bottoms, the bees do not seem to fully occupy the deep, do not move into it as early as the solid bottom board hives, and may be the hives where the bees are not fully drawing out deep foundations. Have others had this same experience?

As for the hive with bees underneath, I'm wondering if the large group underneath had a queen with them that failed to return to the interior of the hive after a mating flight, but wound up under the bottom board. This could explain the calm nature of the hive, the large group of bees under it, the polished cells and lack of brood in the hive, and the absence of laying workers in the broodless hive. Thoughts?

[Wally]

That is one of several reasons I left screen bottoms and went back to solid bottoms. They don't realize it is an outer wall of the hive, therefore they don't try to find their way in. They think they are in.

[Newbee Jim]

Wally,

What are some of the other reasons for not using a screened bottom board?

[Wally]

Grass growing up through them


No brood in the lower portion of the bottom box.


moths and beetles raising on the forgotten slide-in board.


cleaning of bottom board


Maybe others I can't think of right now.