''Osmia uncinata'', the pinewood mason bee, is a species of solitary bee from the family Megachilidae It is an Arctic-alpine species which is found in the northern

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

, in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

it is a Biodiversity Action Plan priority species.

Description

''Osmia uncinata'' is a wasp like mason bee with a yellow and black striped thorax which is quite variable in its colour and the degree of hairiness shown. They measure between 7mm and 15mm in length.

Habitat

Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...

''Osmia uncinata'' is closely associated with relicts of the ancient Caledonian Forest, being found in woodland clearings, along paths through woodland, and on adjacent roadside verges where the principal forage plant, birds-foot trefoil ''

Lotus corniculatus ''Lotus corniculatus'' is a flowering plant in the pea family Fabaceae, native to grasslands in temperate Eurasia and North Africa. Common names include common bird's-foot trefoil, eggs and bacon, birdsfoot deervetch, and just bird's-foot trefoi ...

'', is well established.

Distribution

In the United Kingdom ''Osmia uncinata'' is confined to the northern Scotland. In Europe its distribution covers northern Europe and the mountains of central Europe east into Asiatic

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

Biology

In Scotland the flight period is from late April or May to early July. This species has a single-brood in any season. It chooses preexisting cavities: insect burrows in dead wood or bark, especially those of the longhorn beetle '' Rhagium inquisitor'' and has used drilled borings in wooden blocks; between the thick bark of pine trees. The cell partitions and nest plug are made of leaf mastic. The nesting sites require full exposure to the sun. The eggs are laid in these small cells, which the female then seals with a reserve of food. The larva develops to a pupa and an adult while sealed in the cocoon, where it overwinters. The adults emerge in the spring to mate and to set up their own nests. On the continent ''Osmia uncinata'' is polylectic and has been recorded as utilising pollen sources from plants belonging to 10 different families. In Scotland, both males and females have been observed visiting ''Lotus corniculatus'', broom ''

Cytisus scoparius ''Cytisus scoparius'' ( syn. ''Sarothamnus scoparius''), the common broom or Scotch broom, is a deciduous leguminous shrub native to western and central Europe. In Britain and Ireland, the standard name is broom; this name is also used for oth ...

'', bilberry ''

Vaccinium myrtillus ''Vaccinium myrtillus'' or European blueberry is a holarctic species of shrub with edible fruit of blue color, known by the common names bilberry, blaeberry, wimberry, and whortleberry. It is more precisely called common bilberry or blue whortle ...

'' and rowan ''

Sorbus aucuparia ''Sorbus aucuparia'', commonly called rowan (UK: /ˈrəʊən/, US: /ˈroʊən/) and mountain-ash, is a species of deciduous tree or shrub in the rose family. It is a highly variable species, and botanists have used different Circumscription (taxo ...

'', but these latter three may be nectar sources for the adults only Meadows which border pine woods are possibly an important source of food by providing nectar to fuel the adults' flight and pollen to be provided for the larvae. The chrysidid wasp '' Chrysura hirsuta'' which is a known

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

of the closely related ''

Osmia inermis ''Osmia inermis'', the mountain mason bee , is a species of mason bee from the family Megachilidae which has a Holarctic distribution. Description A small matt black bee, the females are 10mm long and show some pale hairs on the body while the m ...

'', may also be a parasitoid of ''Osmia uncinata'' as the wasp has been found in woodland sites where ''O. uncinata'' also occurs while ''O. inermis'' is not found in woodland.

Conservation

In Scotland it is Listed as vulnerable, the main threats to ''Osmia uncinata'' are the reduction of available habitat, the loss of the open areas within the forest and increased shading of the forage plants. Dead pine wood should be retained to provide nest sites, and the natural regeneration of the forest should be encouraged. As this species has a boreo-alpine distribution, the relict populations in Scotland are probably going to be negatively affected by

anthropogenic climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

. Measures taken to conserve other species found in Caledonian forest should benefit this species. Attempts to encourage them to use artificial nests in Scotland were unsuccessful but did find other rare species of arthropod such as '' Clubiona subsultans''. ''Osmia uncinata'' may be rare in Scotland due to a combination of the limited availability of the combination of old trees in sunny positions, beetle burrows (especially as ''Rhagium inquisitor'' is a scarce species in Scotland), and the availability of patches of bird's-foot trefoil.

References

{{Taxonbar, from=Q2414567 Hymenoptera of Europe uncinata Insects described in 1869 Taxobox binomials not recognized by IUCN