In addition, Dr. Vaissiere says the space separating the two layers of 5-mesh screen must never be less than one quarter inch and not more than five sixteenths of an inch. He also suggests a metal slide be used to help the tray slide easily. There are several reasons beekeepers might trap pollen, according to Dr. Vaissiere. The most obvious is a a protein source for bees. Supplementary feeding is desireable for brood rearing and absolutely essential if colonies are expected to produce drones.
Trapping can protect colonies from pesticide poisoning if contaminated pollen is suspect.
In addition, pollinating efficiency of bee colonies on crops often increases when traps are used and pollution monitoring is also possible by analyzing pollen collected downwind from smelters or other smoke stack industries. Collecting pollen for human consumption, of course, is also a goal for some persons. But beekeepers should be careful, Dr. Vaissiere said, because potential allergy by the consumer is always a real possibility. Colonies with medium sized populations appear to be more efficient than larger of smaller colonies 2. Collecting improves when unsealed brood is present 3.