The blue orchard bee: A native managed pollinator

Christelle Guédot Department of Entomology

Most important insect pollinators: Bees

1. Feed on nectar and pollen 2. Pollen collecting structures (scopa, corbicula) 3. 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 Andrena

Jeremy Early Wikimedia Commons http://www.natures desktop.com/images/wallpapers/1600x120 0/insects/bee-collecting-pollen.jpg

John B. Pascarella, Sam Houston State University pollinator.info

Why are bees important?

Whole foods and Xerces Society " Share the Buzz " campaign (2013)

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

Native Exotic

T'ai Roulston, University of Virginia

Bees: distinguishing characteristics

Bees

Robust Hairy Flat rear legs Feed on nectar and pollen

vs. Wasps

Slender Smooth Slender legs Predators mommammia Flickr James Cane

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

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

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 Photos: Edward Ross, Darrin O’Brien, Matthew Shepherd

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 Christelle Guédot, UW-Madison - Incompatibility: bees must move between inter-compatible cultivars in different rows

Flower morphology ♂ organ ♀ organ ≡ Pistil

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 http://appleharvester.blogspot.com/2011/05/king-blossom.html

Christelle Guédot, UW-Madison

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 Cell1 Mud partitions Provision Egg Front

The blue orchard bee

Females 5 th Prepupa instar larva inside coccon White pupa Black pupa Adult Male Female 0.4 0.6” long

Life cycle of blue orchard bee

Eggs hatch, larvae grow into pupae

Late March April - May June Sept - March

Dormant adults

July - Aug

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 http://seabrookeleckie.com/

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 24-48 hrs after warming - females emerge 1-3 days later

Why the blue orchard bee?

• Native • Commercial use in 1970’s • Forages in cool weather > 54°F • Visits many tree species: discoverlife.org:

Osmia lignaria

distribution Designed by The Polistes Corporation almonds, apple, pear, cherry, apricot,…

Why the blue orchard bee?

Foraging behavior and pollination effectiveness % Stigma contact

Osmia Apis

(P)

Apis

(N) Almond 98.7

67.3

39.5

Apple 97.7

32.7

Christelle Guédot, UW-Madison Pear 98.7

51.8

19.0

http://www.ars.usda.gov/Research/docs.htm

?docid=18333

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: 85-100% Dandelion http://www.swcolorado

wildflowers.com

Golden currant

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: 300-600 ft Max. foraging range: 1,300 ft Homing ability: 4,000 ft

Apple yield with blue orchard bee

Commercial Apple Orchard, Utah Apple Variety McIntosh Red Delicious Golden Delicious Jonathan Rome Total Apple yield (bushel) 1977 + 1978 Honey Bee 4380 1979 + 1980 Blue orchard bee 5186 986 204 430 184 6184 3248 288 417 307 9446 53% increase

Why the blue orchard bee?

Commercial cherry orchard, Utah Year 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Pollinator Honeybee Honeybee Honeybee Honeybee Honeybee Honeybee Blue orchard bee Blue orchard bee Blue orchard bee Blue orchard bee Blue orchard bee Blue orchard bee Cherry yield (Kg) 3,040 5,545 4,820 3,695 14,875 4,150* 16,935 4,415** -* 6,680*** ♀ BOB increase 5.44

2.17

4.21

1.03

2.45

0.62

* Freezing event; ** missed timing on BOB release; ***high bee predation by birds

Number of females

Optimal number of nesting females for adequate pollination Blue orchard bee # nesting females/acre # females/tree Almond 300 3 Apple 250 2.5

In comparison, need 1 - 2.5 honeybee hives / acre (typically 30,000 - 50,000 workers / hive)

Pollination efficiency Flower efficiency and fidelity

• 75 flowers per “load” of pollen and nectar • 15-35 loads per provision Christelle Guédot, UW-Madison • 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: 85-100% orchard flower pollen

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 http://www.sare.org/Learning Center/Books/How-to-Manage-the-Blue Orchard-Bee

Where to obtain bees and materials

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

Nesting blocks

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

Nesting cavities

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

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

A typical BOB season

Example for Northern Utah 1) March/April • • About two weeks prior to expected bloom: Check flower development Check weather forecast

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

A typical BOB season

3) March/April Release BOB population (200-300 females + 400-600 males per acre for full pollination in almonds, cherries, apples, and pears)

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

A typical BOB season

5) June through August • Monitor development with monthly development checks Select 10 male cocoons from different nests

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)

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

Chalkbrood fungus Recently emerged male covered with migratory nymphs of hairy-fingered mite

Summary

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

Spray guide

Acknowledgements

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