Osmia leaiana (Kirby, 1802)

Osmia leaiana colonises a wide variety of habitats as long as there are large populations of Asteraceae and deadwood structrures. It can be found in open woodland, woodland and hedgerow edges, gravel pits and quarries, ruderal areas, extensive pastures and meadows as well as gardens and parks (SwissBeeTeam 2019).It nests in pre-existing cavities like insect burrows in dead wood and bore holes in wooden blocks, hollow stems and holes in pithy stems or holes in stones and walls. The cell partitions and nest plug are made of chewed leaves (e.g., from Rosa) (Benoist 1931, Romasenko 1980, Westrich 1989, Müller et al. 1997, Banaszak and Romasenko 2001). This species is oligolectic, in that it prefers to forage upon a narrow range of flowering plant species, specifically on Asteraceae (Westrich 1989, Müller et al. 1997, Amiet et al. 2004, unpublished data, A. Müller pers. comm. 2014).Development may be annual or biennial. In the latter case, the species spends the first winter as a resting larva and the second winter as an imago. The main flight period for males is from early May to late July, and for females from late May to late August (Gogala 2013, SwissBeeTeam 2019). In Türkiye, it was reported flying until second half of September (Grace 2010).