1. An Evaluation of Georgia’s Mason Bees And Their Nesting Preferences
(Megachilidae: Osmia species)
And Their Nesting Preferences
Nicholas Glynn Stewart and M. A. Schlueter 1

2. NATIVE-BASED POLLINATION SYSTEMS:
Basic Description  Rationale  Required Knowledge
An Ecosystem Service where the Pollination is provided IN TANDEM with the natural system
A Native-Based Pollination System is an agro-ecosystem which depend upon the native Apoidea to provide all the necessary pollination services a particular crop would ever require
The most abundant native species which were Inherently present and participating in pollination services are known as “Target” native pollinators

3. Osmia SPECIES: Spring 16 Species in GA (28 SPECIES)
Common North-East; Uncommon in South
Cavity/Stem-nester, 28 species
Early spring species in GA, rarely persisting beyond the end of April
Ranging from one-third the size of a honeybee to slightly larger
The majority of species are dark blue (often appearing black in the field) with a few that are brown, black, and one rare bright green one

4. The MASON BEES (Osmia sp.): An Opportunity Presents Itself…
In North Georgia, Osmia are some of the earliest bees to emerge each year
Early- to Mid-March
Prior to the apple bloom – typically occurring in mid-April (the 1st mass floral food resource) - NO FOOD IS AVAILABLE
Females immediately SCATTER in search of suitable nesting sites
Food availability
Nesting habitat
Early Blooms in 2011 and ‘12 provided a booster to the Osmia populations, resulting in a bumper year
2010 (TYPICAL) – (9) Osmia collected
2012 (EARLIEST ON RECORD) – 311 Osmia collected
Why Should we care?

5. Currently Managed Species: THE Horn-Faced & Blue Orchard Mason Bees
Using simple measures in Osmia rich regions, some Mason Bee species have become easily MANAGEABLE POLLINATORS
Currently Managed Species:
THE Horn-Faced & Blue Orchard Mason Bees

6. Pollination Efficiency of Osmia
7 Mason Bees
Osmia are EXCEPTIONAL POLLINATORS of Rose-Family agricultural crops
LIKE - Apples, peaches, plums, nectarines, cherries, almonds, pluots...
One mating pair of Osmia
have been shown to effectively pollinate an
entire apple tree in full bloom
545 Honey Bees 6

7. Basic Description  Rationale
GOALS:
Basic Description  Rationale
TRY TO ENCOURAGE Osmia to remain in and settle at our orchards using EARLY BLOOMING FLORAL RESOURCES and NEST HABITAT
PROMOTE AS MUCH NESTING as possible within easily collected and transported hollow TUBES and NEST BOXES
DETERMINE which NEST MATERIAL (Tubes vs. Boxes; Optimal Diameters) is best:
Resulting in the most females rearing young (FILLING TUBES)
Give the most viable offspring ultimately
DECIDE if PROVIDING FLORAL RESOURCES is worthwhile versus only NESTING HABITAT (Floral Nesting Plots vs. Nesting Plots alone)

8. Species with Management Potential:
The Blue Orchard Bee
CONTROL SITES
Starting Number - Tubes/Holes
Raw Totals
% Filled Holes
Cells per Filled Hole
Bees/Coccon per Filled Hole
Hole Diameter
Filled Holes
Cells
Coccon/ Pre-Adults
6 mm (tube) 40 1
0.025
7 mm (tube) 2
8 mm (tube)
0.000
7 mm (insert) 80 7 48 25
0.088
6.85
3.57
8 mm (box)
304 14 58 12
0.046
4.14
0.86
TOTALS
504.00
23.00
109.00
38.00
0.04
2.80
1.09
FLORAL SITES
Hole Diameter
Starting Number - Tubes/Holes
Raw Totals
% Filled Holes
Cells per Filled Hole
Bees/Cocoon per Filled Hole
Filled Holes
Cells
Cocoon/ Pre-Adults
6 mm (tube) 40 11 82 65
0.275
7.45
5.91
7 mm (tube) 2 4 1
0.050
2.00
0.50
8 mm (tube) 20
10.00
5.50
7 mm (insert) 80 6 26 8
0.075
4.33
1.33
8 mm (box)
304 13 54
0.043
4.15
0.46
TOTALS
504.00
34.00
186.00
91.00
0.10
5.59
2.74

9. Species with Management Potential:
The Blue Orchard Bee
TUBE COMPARISON
Hole Diameter
Starting Number - Tubes/Holes
Raw Totals
% Filled Holes
Cells per Filled Hole
Bees/Coccon per Filled Hole
Filled Holes
Cells
Coccon/ Pre-Adults
6 mm (tube) 80 12 82 65
0.150
6.83
5.42
7 mm (tube) 3 6 2
0.038
2.00
0.67
8 mm (tube) 20 11
0.025
10.00
5.50
7 mm (insert)
160 13 74 33
0.081
5.69
2.54
TOTALS
400.00
30.00
182.00
111.00
0.07
6.13
3.53
TUBE COMPARISON (cont.)
Cocoon Size Comparisons
Hole Diameter
Raw No.
Average
of cocoons
min size
max size
avg. size
6 mm (tube) 65
6.89
8.22
7.55
7 mm (tube) 2 xx
8 mm (tube) 11 9 13
10.73
7 mm (insert) 33
8.75 10
9.4975
TOTALS
111
8.21
10.41
9.26

10. Species with Management Potential:
Osmia georgica, O. atriventris & O. pumila
OF the 111Osmia cocoons harvested, nearly 50% were the offspring of one of our native GA species (the 3rd most abundant)
Osmia georgica
Surprisingly, the next most prolific species, responsible for roughly 35% of the viable offspring, is an introduced species to NA – only just last year being recorded for the 1st time in GA
Osmia taurus

11. QUESTIONS? BENEFITS OF OSMIA:
Osmia pollinate open-faced flowers very efficiently
One mating pair can pollinate as effectively as nearly 200 honeybees
Osmia can be easily managed
With little effort, Osmia can be utilized for multiple years and moved wherever needed
IMPLICATIONS OF OSMIA ABUNDANCE PEAKS FOR NATIVE-BASED POLLINATION SYSTEMS:
Osmia abundance peak during PREMATURE BLOOMS Provide POLLINATION RESERVOIR for native-pollination systems during these early seasons
QUESTIONS? 11

12. 3/28/13

13. 3/28/13

14. PHENOLOGY OF AN AGRO-ECOSYSTEM:
The Apple Bloom and Bee Species Emergence/Occurrences
In typical seasons, onset of apple bloom occurs around mid-April
1st substantial floral resource providing food for bees
Prior to onset of bloom, no food available
Emergent males wait for females to emerge
Females begin to search for nesting sites
Based upon food availability, nesting habitat
Osmia, Bombus & Xylocopa Emergence
Dominate TNP Bee Species Emergence
APPLE BLOOM
Vernal Floral Dearth
March
April
May 14