Osmia spinulosa (male) Cherry Hinton Chalk Pits

Distribution
Found south of a line roughly between the Wash and the Severn, although more common in the south of this region. Overseas: Central and southern Europe.
Status (in Britain only)
This species is not regarded as being of conservation concern.
Habitat
A widespread, although not always frequently found species. It is found in a range of open neutral or calcareous grassland habitats, provided that there are plenty of Asteraceae flowering and a degree of litter build-up around tussocks.This is where the snails, whose shells provide the nest site, live out their lives. Hay-cut and hard-grazed grasslands are not suitable for this bee.
Flight period
The species is univoltine, but has a long flight period, being found from mid-May to late September.
Nesting biology
Nests are made within medium-sized old snail-shells, such as those of Cepea nemoralis. The cells are made within the spiral from chewed plant material.
Flowers visited
Males and females of this species are most often visit Asteraceae but many males have been found with orchid pollinia attached to the apical terga (S P M Roberts pers. comm.).
Parasites
G R Else reports rearing the generalist chalcid wasp Pteromalus apum from a nest of Osmia spinulosa (pers. comm.). No cleptoparasitic aculeates have been reared from this species in Britain.

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