Regarding square mesh vs round holes. I used to trap pollen by the ton. Had about 300 pollen traps I made myself. We used the Ontario design, slightly simplified to make it cheaper. All we had was a wood frame with screen on both sides so they had to pass through it twice. The pollen dropped down through a finer mesh screen into a wooden drawer. You wouldn't want 100 per cent efficiency as the bees need pollen. I estimated that they got through with about half the pollen, which is reasonable. The bees adjust the amount of pollen coming in so that they have an adequate supply regardless of how much you take (short of taking it all)

PLB

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm