excluders

Excluders are devices or components designed to prevent passage or entry of specific entities while allowing others to pass. They are used in agriculture, beekeeping, construction, and fisheries to control access and movement without relying on killing or trapping.

In beekeeping, a queen excluder is placed between brood frames and honey supers. It is a grid with openings that prevent the queen from moving into honey storage, while worker bees can pass. This arrangement helps manage brood area and honey production, but can slow colony throughput if the excluder becomes crowded or poorly fitted.

In buildings and homes, excluders include window and door screens, draft excluders under doors, chimney caps, and vent screens. These barriers prevent insects, rodents, and drafts from entering while allowing ventilation. They require regular cleaning and proper fit to remain effective.

In fisheries and aquaculture, aquatic excluders are devices attached to nets or gear to allow undersized fish or non-target species to escape, reducing bycatch. Examples include exit rings or square-mesh panels. These tools require consideration of local regulations and species behavior.

Other applications include protective screens for machinery to prevent debris ingress, and animal-exclusion barriers in gardens and crops. Excluders are valued for offering non-lethal, targeted control, but effectiveness depends on proper sizing, installation, and maintenance.