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The Perfect Storm: Setting the Stage for this Year's Loss
of Honey Bee Colonies
Marla SpivakUniversity of Minnesota
Healthy Honey BeesHealthy Honey Bees
Variety of pollens with different protein contents
Michael Traynor
Umberto Moreno
Foraging trip of bees back when….our landscape contained small farms separated by
windbreaks, and wildlife (pollinator) corridorswww.miriameaglemon.com
Clover was used as a cover crop
Alfalfa was cut at 10% bloom
Healthy honey bee colonies issued many swarms, establishing a large population of feral colonies in
trees and cavities
If a fruit orchard or farm needed bees for pollination, a beekeeper brought in a few
colonies for a handshake
http://www.art.com/
The main health problem of honey bees was American Foulbrood disease
(Paenibacillus larvae, bacterium)
The Treatment
From World War II to the 1980’s
After WWIIAntibiotic use increased to control
American foulbrood
Other Honey Bee Diseases
Chalkbroodfungal disease caused by Ascosphaera apis
1960’s
Nosema apis
Mostly a problem in northern climates where bees are confined during winter
After World War II, our use of pesticides increased
www.hawaii.gov
Pesticide Poisoning
Foragers may die in front of the colony
Micro-encapsulated pesticides (e.g., methyl parathion) and those with long residue are collected with pollen, stored,
and consumed by bees later
Until 1980’s, main problems for honey bees:• Diminishing forage due to land use• Increasing use of pesticides on crops• American foulbrood disease
And for beekeepers:
• Diminishing honey yields • Depressed honey market• Increasing number of bee poisonings
1984
The Tracheal MiteAcarapis woodi
1987: Varroa destructor
Original host Apis cerana, Asian honey bees
Apis cerana Varroa
(Rath, 1999)
Life Cycle of Varroa destructor on Apis mellifera
• Reduced body weight (Schneider and Drescher, 1987)
• Reduced longevity (De Jong et al., 1982)
• Suppressed immune system
(Yang and Cox-Foster, 2005)
• Deformed Wing Virus (De Jong et al.,1982)
• Acute Paralysis Virus (Batuev, 1979)
Impact of Varroa destructor Apis mellifera:
Beekeepers reluctantly resorted to using pesticides to control Varroa
And the mites developed resistance to the treatments
Queen starts laying eggs
Queen stops laying eggs
Mites in brood
Mites on adult bees
Infestation level of mites over a year in northern climate
Honey flow
(Martin, 1997)
(Martin, 1997)
Honey flow
Treatment window
Varroa destructorVarroa destructor has gained the upper handhas gained the upper hand
Apis mellifera
Varroa destructor
Foraging trip of a weakened bee in our modern
landscape:
Neonicotinoid treated canolaAnd many other crops…
Contaminated pollen, nectar, and wax combsLow diversity, low quality pollen
Simple Beekeeping Economics
• Current price of honey (wholesale) = $0.80-0.90/lb• Beekeeper with 2000 colonies, producing 100 lbs/
colony can gross $180,000
• Current price for renting colony for almond pollination = $150/colony
• Beekeeper with 2000 colonies can gross $300,000 during “winter”
Almonds
• In 2006, there were over 550,000 acres of almonds in bloom– at 2 colonies / acre, growers
needed 1.2 million colonies of honey bees
• In 2010, it is projected that 750,000 acres will be in bloom– almond growers will need more
than half of all the commercial honey bee colonies in the US
Recipe for DisasterRecipe for Disaster:1. Resistant Varroa mites2. Old wax combs with disease spores and pesticide
residue3. Reduced forage and DIVERSITY of forage4. Poor bee nutrition5. Crop and urban pesticides6. Depressed honey market7. Increased acreage of almonds,
blueberries, cranberries, etc 8. $$ in pollination contracts 9. Increased movement of bees
10. New pathogens, new pesticides….
“What’s going on with the honey bees?”
Modern Agriculture
International Trade
Chemical Companies
Urban sprawl
Food Supply
Human-centric
landscape Economy
My Goal:
Apis mellifera Varroa destructor
• Breeding honey bees for resistance to diseases and Varroa destructor (“MN Hygienic” line)
• Developing a Varroa sampling plan for beekeepers to help them make educated treatment decisions
• New line of work on the benefits of propolis (plant resin) on immune system of bees
• Promoting non-Apis pollinators: bumble bees, mason bees, leafcutter bees
What we are doing at University of Minnesota