Mason bees benefit from "bee hotels"

Among the most common bees in spring are the European orchard bee (Osmia cornuta) and the red mason bee (Osmia bicornis).

Both species readily accept cavities of "insect hotels" as artificial nesting aids. They build the brood cells of their nests from loamy soil. Usually females develop in the rear cells and males in the front cells.

The nursery of the mason bees can be easily recognized by its clay closure. The red mason bee fits into tubes as small as 5 mm inside diameter. Their nest closures are usually somewhat coarser and more "sloppily" made than those of the somewhat larger European orchad bee.

Especially the red mason bee is considered an effective pollinator of fruit trees. It even surpasses the honey bee in this respect. For this reason, fruit growers use them specifically for pollination.

Image captions:
Mason bee species gather food on a wide variety of flowers, including red clover (Trifolium pratense L.).
European orchard bees (Osmia cornuta) mating at the nest site.
The clay nest seal reveals where mason bees nest.
Male (left) and female (right) of the red mason bee (Osmia bicornis).

English translation of the information panel in the Botanical Garden. Original German text: Dr. Barbara Ditsch, Mandy Fritzsche