The Red Mason Bee
Most of the fruit, vegetables and flowers we grow are dependent on insects for pollination. Insects pollinate approximately 80% of the flowering plants in temperate regions [source]. One of the best known pollinating insects is the honeybee, often seen in the garden or allotment buzzing from one flower head to another collecting pollen and nectar.
With traditional bee-keeping in decline and honeybee populations under pressure from parasitic mites, bees are having a struggle; habitat is under pressure due to urbanisation and modern farming methods. We can help by encouraging bees to live in our gardens and allotments and this does not necessarily mean keeping beehives.
Osmia rufa male waiting for females to
emerge. Picture courtesy Nigel Jones ©.
Not all bees live in colonies, some are solitary and build individual nests. One particular solitary bee, the Red Mason Bee [Osmia rufa], is an excellent pollinator and safe around children and pets. By providing suitable nesting sites, we can encourage the Red Mason Bee into our gardens and allotments and have the pleasure of watching the fascinating life cycle of this attractive little bee.
Life Cycle
Osmia rufa females nest building.
The nests of Osmia rufa are cylindrical hollows. The female divides the hollow into several cells - one for each larva - separated from the next by a wall of mud. The female uses existing hollows for the nest, such as plant stems or old beetle holes, and might build several nests during her short lifetime, which runs for a few weeks from Spring to late June. Although solitary, the bees are gregarious, and often gather together around nest sites, particularly the nest site that they emerged from.
The female provisions each cell with a pile of pollen, lays an egg on top, then caps off the cell with a wall of mud. She is able to determine the sex of her offspring and puts females at the back of the nest and males at the front. During the summer the larvae eat the pollen, then spin a cocoon and pupate, sitting out the winter in the insulating cocoon as fully developed bees.
In Spring, the males emerge first, feed up for energy, then look for females to mate with. Males are slightly smaller than the females and can be observed scouring the territory looking for the opportunity to mate - even if this involves dislodging another male in the process of mating. Once the females have emerged and mated they start building nests and the cycle repeats itself.
Distribution
In the UK Osmia rufa can be found in most parts of England and Wales; it is absent from Northern Ireland and Northern Scotland. It can be found throughout most of mainland Europe and has been reported as far north as Sweden and Norway, North Africa to the south and Iran to the east [distribution map].
[Visitors from North America might be interested in a similar bee, the Blue Orchard Mason Bee - Osmia lingnaria - that lives in the region. A useful source of information can be found on the links page.]
Videos
Videos of these bees can be found here.