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

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

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

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?

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

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

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)

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

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

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

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

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3/28/13

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