Editing Langstroth hive (section)

=== Bottom board and entrance reducer ===
The bottom board is almost always exterior-grade plywood, to resist water damage. It keeps dampness and some pests out of the lower brood chamber. It rests on wooden rails, which in turn rest on the ground. Some beekeepers place the rails on bricks or sand to reduce water and termite damage. Langstroth's patent shows a wooden hive stool that lifts the hive several feet from the ground to a convenient working height for a beekeeper. A white plastic sheet is sometimes coated with a slightly sticky substance, and slid over the bottom board to trap and count fallen [[varroa]] mites, a bee parasite that can infest hives.

The entrance reducer is a square bar of wood to help the bees manage air circulation. Bees naturally manage their hive's temperature with fanning, clustering, and shivering. The reducer helps bees stay warm in winter, and fan less energetically in summer. It may drop into notches in the wooden rails or the bottom board. It has two different sizes of bee entrance notches cut into it, on different sides of the bar. In winter, the reducer is turned so that the smallest notch forms the entrance. This reduces the air flow and helps the bees to keep the hive warm. In spring and fall, it is turned so that the larger notch forms the entrance. In hot weather or full nectar season, the entire reducer can be removed to help cool the hive and permit more traffic to the fields.

In winter when the bees are too slow-moving to defend the hive, the entrance reducer may be supplemented with a mouse barrier to keep mice out of the hive.

Modern hives usually extend the bottom board slightly beyond the entrance to form a landing area, so that in nectar season, larger numbers of bees can land and walk into the hive. Langstroth's patent supplemented this with a cloth landing area supported on two wooden arms.

In Langstroth's patent, although the hive as a whole was level, the bottom board was slightly tilted toward the entrance so that liquid water would run out of the hive. The tilt also helped the bees to push dirt, debris, and dead bees out of the hive entrance. Modern commercial hives usually have level bottom boards.

Langstroth's patent entrance included two traps designed to attract [[wax moth]]s away from the bee entry. These were loosely mounted so that a beekeeper could remove and destroy wax moth larvae and pupae.