1. A native managed pollinator Department of Entomology
The blue orchard bee:
A native managed pollinator
Native to North America
Temperate zone fruit trees: almonds…
Manageable pollinator, supply, rearing, developmental biology
Christelle Guédot
Department of Entomology

2. Most important insect pollinators: Bees
Feed on nectar and pollen
Pollen collecting structures (scopa, corbicula)
Display floral constancy (strong tendency to visit flowers of the same type on a single foraging trip): important for pollination because minimizes pollen wastage and stigma clogging with pollen from other species
Osmia bicornis
Jeremy Early
Wikimedia Commons
Andrena
John B. Pascarella, Sam Houston State University
pollinator.info

3. Why are bees important?
Whole foods and Xerces Society "Share the Buzz" campaign (2013)

4. Bees At least 25,000 known species of bees
Social vs. solitary, 90% being solitary
~4,500 of solitary spp. in North America
Wisconsin: ~390 spp. (Wolf and Ascher, 2008)
Stephen Buchmann
Smallest North American bee (Perdita minima) on largest female carpenter bee
T'ai Roulston,
University of Virginia

5. Bees: distinguishing characteristics
Bees vs. Wasps
Robust Slender
Hairy Smooth
Flat rear legs Slender legs
Feed on nectar and pollen Predators
mommammia Flickr
James Cane

6. Life cycle of a solitary bee
Mining bee (Andrena sp.): a year in its underground nest as egg, larva, and pupa before emerging to spend a few weeks as an adult.
Photos: Dennis Briggs

7. Ground-nesting solitary bees
~70% of native bee species nest underground
Resemble ant-nests from above ground
Nests may be as deep as 3’
Photos: Eric Mader, Matthew Shepherd, Dennis Briggs

8. Cavity-nesting solitary bees
~30% of native species nest in cavities
Nest in hollow plant stems, old beetle borer holes, man-made cavities
Nest have tunnel partitions constructed of mud,
leaf pieces, or sawdust
Artificially managed for some crops
About 30% of our native bees nest as solitary individuals in wood tunnels, usually hollow stems, or the abandoned beetle borer holes found in dead trees, or stumps.
Photos: Edward Ross, Darrin O’Brien, Matthew Shepherd

9. Bees for fruit tree pollination
Impediments to bee pollination on fruit trees
Early season; bad weather
Short flowering period: 2-3 weeks
Flowers receptive only few days
Cool temperatures slow pollen germination
ovules might degenerate before fertilized
Incompatibility: bees must move between inter-compatible
cultivars in different rows
Christelle Guédot, UW-Madison

10. Flower morphology
♀ organ
♂ organ
≡ Pistil

11. Apple pollination
Pollinate king blossoms (first to open, produces larger fruit)
Pollinate blossoms with large amount of compatible pollen for high number of seeds, which relates to fruit size and shape
Size of fruit affected by number fruit produced; thinning might be required
Christelle Guédot, UW-Madison

12. The blue orchard bee Osmia lignaria, a native Solitary but gregarious
Nest in pre-existing cavities
Only females provision nest
Collect nectar and pollen for provision
Collect mud for nesting material
Back
Front
Provision
Egg
Cell1
Mud partitions

13. 5th instar larva inside coccon
The blue orchard bee
Females
Male Female
” long
Prepupa
5th instar larva inside coccon
White pupa
Black pupa
Adult

14. Eggs hatch, larvae grow into pupae
Life cycle of blue orchard bee
Eggs hatch, larvae grow into pupae
Late March
April - May
June
The bees overwinter as adults. They emerge when it’s about 55 degrees, males first then females a few days later. They mate, and the males are dead within two weeks. Females forage for a few days, then begin nesting in available holes. One hole is owned for each female. 25 trips or so of pollen gathering makes a pea sized mass of pollen/nectar. She backs in and lays an egg, then seals that chamber with about trips of mud gathering. The egg hatches within a week or so and begins to eat the pollen mass. After a month, the larva has eaten all of the pollen and then spins a cocoon. Later in the summer it metamorphosis into an adult bee, and then hibernates through the winter.
July - Aug
Sept - March
Dormant adults

15. Identifying females vs. males
Males smaller than more robust females
Males have longer, more slender antennae
Males do not have scopa, females do
Males have more facial hair
Males often have additional hairs on face “mustache” or extra yellow maculations

16. Life history Fecundity: 10 - 20 eggs / nesting female (2.5 - 6 ♀ eggs)
Longevity adult females: ~20 days
Females build ~ 2-4 nests in lifetime
Emergence: - males emerge hrs after warming
- females emerge 1-3 days later

17. Why the blue orchard bee?
discoverlife.org: Osmia lignaria distribution
Designed by The Polistes Corporation
Native
Commercial use in 1970’s
Forages in cool weather > 54°F
Visits many tree species:
almonds, apple, pear, cherry, apricot,…

18. Foraging behavior and pollination effectiveness
Why the blue orchard bee?
Foraging behavior and pollination effectiveness
% Stigma contact
Almond
Apple
Pear
Osmia
98.7
97.7
Apis (P)
67.3 -
51.8
Apis (N)
39.5
32.7
19.0
Christelle Guédot, UW-Madison

19. Why the blue orchard bee?
Blue orchard bees readily move from tree to tree and row to row
Facilitate cross-pollination, rather than pollination within a tree or within a cultivar
Preference for fruit tree pollen: %
Dandelion
Golden currant

20. Why the blue orchard bee?
Active at low light levels and low temperatures
33+ hours foraging in 5 days
15+ hours by honey bees
Usual foraging range: ft
Max. foraging range: 1,300 ft
Homing ability: 4,000 ft

21. Apple yield with blue orchard bee
Commercial Apple Orchard, Utah
Apple yield (bushel)
Apple Variety
Honey Bee
Blue orchard bee
McIntosh
4380
5186
Red Delicious
986
3248
Golden Delicious
204
288
Jonathan
430
417
Rome
184
307
Total
6184
9446
53% increase

22. Why the blue orchard bee?
Commercial cherry orchard, Utah
Year
Pollinator
Cherry yield (Kg)
♀ BOB increase
1992
Honeybee -
1993
3,040
1994
5,545
1995
4,820
1996
3,695
1997
1998
Blue orchard bee
14,875
5.44
1999
4,150*
2.17
2000
16,935
4.21
2001
4,415**
1.03
2002 -*
2.45
2003
6,680***
0.62
* Freezing event; ** missed timing on BOB release; ***high bee predation by birds

23. Number of females
Optimal number of nesting females for adequate pollination
Blue orchard bee
Almond
Apple
# nesting females/acre
300
250
# females/tree 3
2.5
In comparison, need honeybee hives / acre (typically 30, ,000 workers / hive)

24. Pollination efficiency
Flower efficiency and fidelity
75 flowers per “load” of pollen and nectar
15-35 loads per provision
75 X 25 (avg.) = 1,875 flower visits per provision
Female provisions 7 – 12 cells in her life
A single female visits 10,000-20,000 flowers in her lifetime!
Remember: % orchard flower pollen
Christelle Guédot, UW-Madison

25. How to manage the blue orchard bee
What do you need to have blue orchard bees in your orchard?
Care, attention, enthusiasm
Bee stock
Nesting equipment
Appropriate storage facility
Proper handling

26. Where to obtain bees and materials

27. Nesting shelters Attach shelter on tree or fence post
Orient SE for longer foraging activity (and more attractive to nesting females)
James Cane, USDA ARS
Shelter with wooden blocks and chicken wire

28. Nesting blocks Prefer wood blocks
Reeds
Prefer wood blocks
Paper straws in cavities help for handling
and storage
Wafer boards

29. Nesting cavities 19/64” (7.5 mm) hole diameter 6” (15 cm) long
Plan on 3-5 nesting cavities per female released

30. Nesting material Mud is a vital nesting material
Clayey mud, not sand or loam
Need safe place for gathering mud, within 20-50ft. of nest

31. A typical BOB season Example for Northern Utah March/April
About two weeks prior to expected bloom:
Check flower development
Check weather forecast

32. A typical BOB season 2) March/April
Set up nesting materials and mud sources
Incubate bees at 72-76°F (22-25°C)
Emerged bees can be held at 37-41ºF for ~a week

33. A typical BOB season 3) March/April
Release BOB population ( females males per acre for full pollination in almonds, cherries, apples, and pears)

34. A typical BOB season 4) May/June Retrieve nesting materials
Move nests to summer storage (avoid excessive heat, direct sun)
Take measures to avoid parasitism
Adult female chalcid wasp, Monodontomerus
Blue orchard bee nests by black light trap Note large numbers of drowned Monodontomerus in tray
Adult female chalcid wasp,
Melittobia chalybii

35. A typical BOB season 5) June through August
Monitor development with monthly development checks
Select 10 male cocoons from different nests

36. A typical BOB season 6) Mid/late September
Move nests to winter storage (refrigerator)
Check small sample of females from different nests to be sure that all adults
Best if population held for 1 week at 55°F before being placed in artificial wintering at 39°F
Require minimum of 3 months wintering: adults go dormant (diapause)

37. Hairy-fingered pollen mite, Chaetodactylus krombeini
A typical BOB season
7) November/December
Quantify population
Remove parasites and diseased bees (now dead)
Prepare nesting materials for the following season
Hairy-fingered pollen mite, Chaetodactylus krombeini
Recently emerged male covered with migratory nymphs of hairy-fingered mite
Chalkbrood fungus

38. Summary Blue orchard bees are superb orchard pollinators
BOBs can be used alone or along with honey bees
Easy management
Bees are safe

39. Spray guide

40. Acknowledgements Jordi Bosch Theresa Pitts-Singer William P. Kemp
USDA-ARS Beelab