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Wild bee pollination at UC Davis
• Dr. Neal Williams• Wild bee contributions to crop pollination• Landscape effects on wild bee communities• Effects of habitat enhancement on bees and pollination • Plant choice for creation of bee habitat• Other impacts of pollinator enhancement, e.g.
pests/beneficial insects
Talk Overview
• What are native bees?• Why and how are native bees important to almond
pollination?• Managing orchards to support alternative
pollinators• Alternative Managed Bees: the Blue Orchard Bee• Establishing pollinator habitat to support native bees
What Are Native Bees?
• Bees that originate in CA • Does NOT include Honey Bee, which is from Europe
• ~ 1500 species of native bees in CA, ~450 in Sac Valley
Honey Bees:• 1 species• Social• Live in Hives• Produce Honey
Native Bees:• Many species • Typically Solitary• Many nest in twigs,
hollow stems, or underground
Diversity of almond pollinators
Spring bee
Digger beeBumble bee
Long horned bee
Hairy-leg bee Tiny dark beeSmall dark bee
Blue orchard bee Other mason bee
Slide credit: K Ward
Why are native bees important in an almond system?
Nut Yield and Quality
Slide credit: K Ward
Why are native bees important in an almond system?
Pollination
Nut Yield and Quality
Slide credit: K Ward
Why are native bees important in an almond system?
Number of Bees
Pollination per bee
X = Pollination
Nut Yield and Quality
Diagram: K Ward
Necessity of outcrossing
Native Bee Potential• Increasing concerns about honey bee availability and health• Synergistic effects: make honey bees more efficient pollinators• Fly in worse weather conditions
Dr. Claire Brittain
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without WBs with WBs
% fr
uit s
et p
er o
rcha
rd
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without WBs with WBs
% V
isits
suc
cess
ful p
ollin
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n
Data C. Brittain, graph from K Ward
21% 16%
Orchard Orchard
Single visit pollination by honey bees
Fruit set
Wild bees make honey bees better pollinators
Weather conditionsNative bees and other wild pollinators willing to fly in worse weather conditions than honeybees
Data C Brittain from K Ward
Managing for native bees in your orchard: the blue orchard bee
• Exploring potential for Blue Orchard Bees as an alternative managed bee
• Can nest in man-made nesting blocks of wood or cardboard
• ~ 800-1000 BOB females needed to pollinate one acre of almonds effectively
Nest in provided blocks, which can be collected and
stored
Offspring in bee blocks mature
Winter: chill nest blocks to ensure
synchronous emergence
Warm cocoons and place into orchards for bees to emerge
Bees pollinate crop
Blue Orchard Bee Management
Cycle
Feb-March
April
April - September
Dec - JanuaryEarly Feb
Benefits of adding pollinator habitat to almond systems
• Improve nest retention for Blue Orchard Bees?
• Forage for honey bee colonies before almond bloom
• Improve honey bee nutrition and health
• Forage and nesting resources for native bees
Proportion of HB movements across vs. down the orchard rows
Key considerations
• Develop a mix that blooms at the right times (i.e. provides resources before and after almond)
• Identify plant species suitable for almond growing regions• Develop methods for establishing plantings that are cost and labor
effective
Bee visits to almond mix
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2/22/2013 3/22/2013 4/22/2013
Num
ber o
f bee
s per
plo
t
Honey bees
Wild bees
Lost Hills 1614Honey Bee 1017Native Bee 515
BLOOM
Graph: K Ward
Flower strips did not compete with almonds
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0.01
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0 50
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ControlRestoredWildflower strip
Mid bloom
Late bloom
Distance into orchard
Alm
ond
flow
er v
isita
tion
Graph: K Ward
Planning for wildflower plantingsSite considerations
• Space and time available• Proximity to crop• Management practices• Weed pressure• Exposure
Planting preparation
• Essential to control weeds prior to planting
Site preparation methods
Diagram: K Ward
Establishing wildflowers
• No cultivation is key!• At most, lightly scratch soil
prior to planting with a chain harrow
• Spread seed with a dropseederor hand-cranked seeder
• Cultipack (ring-roll) to ensure good contact with soil
Ongoing maintenance
• Be attentive to wildflowers as they begin to grow and monitor for weeds
• Control grasses with grass-specific herbicides
• Hand-pull small patches or weeds or spray with a targeted herbicide application
• Remember that broadleaf herbicides will also harm wildflowers
• Consider spraying or mowing plot perimeter
• Plot should reseed from year to year
Acknowledgements
• Researchers:• Neal Williams, Kimiora Ward, UCD• Theresa Pitts-Singer, USDA ARS• Claire Brittain, project ICP
• Growers:• Amy Abele, Mary Fahey, Pat and
Kim Gallagher, Dave and Diane Gilmer, Rachael Long, Wonderful Orchards, Muir Glen
Additional Resources
• Xerces Society: regional plant lists, pollinator habitat installation guides, etc:http://www.xerces.org/pollinator-conservation/
• USDA-ARS Blue Orchard Bee Manual: http://bit.ly/2kaVca3
• Project ICP: [email protected]
Save the Date! Almond Field Day
March 22Arbuckle, CA
