The purpose of a metal queen excluder in an American Langstroth beehive is to prevent the queen bee from accessing the honey supers, which are the boxes placed above the brood chambers where honey is stored. Designed to fit regular 8 frame beehives.
The excluder is designed with gaps that are large enough to allow worker bees to pass through but too small for the larger queen bee to do so. This ensures that the queen lays eggs only in the brood chambers and not in the honey supers, which could lead to brood and other contaminants mixing with the honey.The use of a metal queen excluder has several advantages.
Metal excluders are robust and can last for many years, possibly decades. They are also less likely to damage the wings of worker bees due to their smooth edges. The gaps in metal excluders are typically rounded, which allows worker bees to pass through more easily compared to the squarer gaps found in plastic excluders. Metal excluders are also easier to clean than plastic ones, which is beneficial at the end of the beekeeping season.
However, restricting the queen to the brood chambers can lead to congestion, which may prompt the hive to swarm. Regular maintenance is also required to ensure that the gaps do not become blocked with wax or propolis.
Despite these potential drawbacks, many commercial beekeepers use metal queen excluders for ease and time savings during honey harvest, as they allow for quick removal of honey boxes without the need to inspect frames individually. For hobbyist beekeepers, the decision to use a queen excluder is often a matter of personal preference and beekeeping philosophy.