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

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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