Osmia bicornis (Linnaeus,1758) commonly known as “Red Mason Bee”
Male: 8mm to 10mm in length Female: 10mm to 12mm in length.
Flight season: late March to early July. (More active during the spring months).
A widely distributed and common species U.K. (As far north as Perthshire). Although not so common northern England and is scarcer in Scotland and Ireland. This species is found throughout much of the Palaearctic, ranging as far north as Sweden and Denmark and extending south as far as Morocco and east to Japan.
Generally speaking this species of bee is not regarded as being scarce or threatened.
Habitat: Very common in lowland Britain. Gardens, parks, wasteland, grasslands and urban spaces.
Flowers visited: Pollen collected from a wide variety of plant species including fruit blossom such as raspberry (Rubus idaeus), plum (Prunus domestica), pear (Pyrus sp.) and apple (Malus sp.).) which makes them early important pollinators for agriculture. They are known to have trichromatic colour vision (being ultraviolet, blue, and green).
Osmia bicornis is a bee species of “mason bees”. They are solitary bees and take advantage to nest in pre-existing holes, as in sandy banks, decaying trees, plant stems, crumbling mortar walls and unmaintained window frames etc. they forage up to approx. 600m from the nest.
The females lay a single egg in each cell, supplied with a supply of pollen, then the cell is sealed.
The cell walls are built from mud, brought to the nest site as pellets held in the bee's mandibles and pressed into position. Osmia bicornis is one of only two British Osmia species which use mud for the construction of their nests, others species use leaf pulp.
The whole process from egg to cocoon stage takes about 20 days. Young males tend to leave the nest earlier than females, because the female cells being larger and needing more food take longer to pupate. Female brood cells tend to be made further inside the nest.
The adults hibernate over the winter months.
Parasites: Monodontomerus obscurus (wasp) Chrysis ignita (Chrysididae Ruby wasp), Chaetodactylus osmiae, (mite) cacoxenus indagator (Fly), Megatoma undata (Dermestidae, Skin Beetles) C. indagator, a member of the family Drosophilidae; may be found in nest the cells eating pollen so starving the bee larvae of its food supply.
This species is part of the order Hymenoptera which consists of bees, wasps, ants, and sawflies.
Males have longer antennae and are smaller in size, notably the females body and head are broader than the males.