1. 3. Materials and methods – Mapping of floral resources
Nest boxes:
• 200 O. bicornis were released as pupae at each of the three nest box sites; adult
emergence was recorded at weekly intervals (figure 2).
• Cells in each nest box were counted and pollen samples taken from each cell.
Quadrat and transect survey:
• Fixed quadrats (2m x 2m) were used to record flower species within Osmia flight
radius around each nest box (figure 1.).
• The number of individual flowers of each species in each quadrat were recorded.
Walk surveys were conducted within grid cells (Figure 3 and 4) to identify any floral
resources not quantified within quadrats.
4. Nest cell construction
Figure 4. Cells constructed against floral abundance between
sites Green = Floristically enriched, Red = Mid point,
Blue = Floristically unenriched. Cell construction rate was more
strongly correlated with floral abundance than floral diversity.
Investigating the influence of floral resource availability on the
nesting behaviour of the solitary bee; Osmia bicornis.
Liam M Crowley 1, Jordan T Ryder 2, Andrew J Cherrill 2 and Keith FA Walters 2
1. University of Birmingham, B15 2TT 2. Harper Adams University, TF10 8NB
2. Field site – West Shropshire
Weekly floral surveys were conducted across a gradient of habitat complexity to determine floristic diversity, abundance and composition within the
foraging range (figure 1).
Cell construction was recorded along with analysis of the pollen provisioned by Osmia bicornis by microscopy (figure 2 & 3).
1. Introduction
The national pollinator strategy aims to boost the number of pollinating insects on commercial farms
by creating specific habitats, tailored to local conditions and native insects.
This study supports the national pollinator strategy by:
1. Investigating floral diversity and abundance on nesting behaviour of the solitary bee; Osmia bicornis.
2. Investigate pollen provisions to determine the presence of any keystone floral species.
Figure 1. Figure 3. Example of stained pollen grains for
analysis. Left to right: Prunus sp., Salix sp.,
Ranculus sp. and Taraxacum sp.
6. Bigger picture
• Floral species found to be important to O. bicornis
reproduction are not specifically addressed in conventional
agri-environment schemes.
• In addition to nectar rich wildflower mixes, future schemes
could support a more diverse pollinator assemblage by
promoting tolerance of specific weed plants, along with
enhanced hedgerows and woodland environments.
• Future laboratory experiments will be conducted to identify
the effect of pollens from keystone versus less favoured
species on larval development.
Figure 2. Left: Osmia release box with nesting trays.
Right: Cells showing eggs with pollen provision.
Osmia bicornis is a
common, polylectic
solitary bee, known to
utilise the pollen of over
34 species from at least
19 plant families!
x
x
x
week week week week week week week week
Green = Floristically enriched
Yellow = Mid-point
Blue = Floristically unenriched
5. Floral and pollen profile
Figure 5. Relative proportions of each species in flower (F) and in pollen
provisions (P).