Osmia Rufa

Osmia rufa or Osmia bicornis is a species of solitary bee, also known as the red mason bee due to its habit of using mud to build small cavities within its nest.

The species is most active during the spring and early summer although it can be seen as far as late June. Despite being classed as solitary, these bees are gregarious. The female is larger/broader than the male and has 2 large horns on the head. The female has a much smaller sting than honeybees or wasps. The male has no sting. Osmia rufa nest in preexisting hollows, choosing not to excavate their own, and have been known to nest in key holes, empty snail shells, plant stems and empty beetle hollows. Male larvae are placed in front of the females within the nest allowing the males to emerge first in the spring. These bees store mostly pollen moistened with a small amount of nectar which is eaten by the larvae during the summer before they rest through the winter in a cocoon. Red mason bees are excellent pollinators.

These bees are not aggressive and will only sting if handled very roughly between the fingers and they are safe to be closely observed by children.