some crops pollinated by bees the honeybee is nature's "workhorse — and we took it for...

Some Crops pollinated by Bees

The honeybee is nature's

"workhorse — and we took it for granted... We've hung our own future on a thread” Prof.

E.O. Wilson Harvard University Insect + Biodiversity Expert + Pulitzer Prize-winning Author

of many books including “ The Insect Societies” + "The Creation: An

Appeal to Save Life on Earth"

What do we mean by Ecosystem Services?

The Problem: Dead Bees outside a hive

US honey colonies (Millions) 1945-2007

Colony Collapse Disorder 2007

Educational Cartoon

Multi-routes of pesticide exposure for honey bees…Received/ accepted/ published… Jan 2012

(How is this paper organized?)

• Abstract – Bees colonies decline + pesticide results• Introduction – Background on Colony collapse

disorder• Results – Short but + 6 Tables of data !• Discussion – Data compared to literature• Materials + Methods: prep + analysis field and lab

methods• Acknowledgements – thanks anonymous reviewers !• References – 36 listed.

Abstract: summary of problem + research

• Neonicotinoid insecticides “blamed” – known to be highly toxic to bees– 2 types are researched in this paper: – Clothianidin (CL)+ – Thiamethoxam(TH)

• How can bees be exposed?– Foraging flowers– seed planter exhaust – soil

Introduction: Background Info• Bees are important crop pollinators

• Bee populations are declining worldwide What are potential causes?

– Parasitic mites: hard to kill = spread easy

– Viruses: also spread easily

– Pesticides: insecticides, miticides, fungicides, herbicides are found in pollen + bee wax

– high fructose corn syrup: may contain toxins

Deadly parasitic Varroa mite on the back of a honey bee. (Credit: Scott Bauer)

Intro. – Neonicotinoid Pesticides

• Low vertebrate toxicity: thought “safe”

• Highly toxic to bees: LD50 = 22-44 ng/bee (contact) or 3 ng/bee (oral)– LD50 = lethal dose to kill 50% of tested critters– 1,000,000,000 ng = 1 gm

• Persistant: half-life = 148-1155 days for CL– ½ life = time for half of substance to disappear

• Effect: insect neural nicotinic acetycholine receptors to “fire” continuously leading to death

Intro: Corn• Largest “single use” of land in N. America

– 35.7 million hectares (2010)

• Neonicotinoid Pesticides are applied to the seed coats before planting on 99.8 % of corn (except for the 0.2% organically grown).

• Applied at 0.25-1.25 mg/kernal – x 12,500 kernals/hectare– x 35.7 million hectares =

• Dead bees tested had Clothianidin or Thiamethoxam• Healthy bees + healthy hives had no CL or TH

Results: Table 1 – Soil Samples

Soy and Corn soils show levels of pesticides.

Table 1 - Soils

• Soil residues even after 2 years• easily spreads off-site

Table 2 – Talc samples

Table 2 = Talc

Talc residues are very high in pesticidesLevels are toxic and very mobile

Table 3 - Corn Pollen samples

Table 3 - corn pollen

Table 4 - Bee pollen samples

Table 4

Table 5- Bee and hive samples

Table 5

Table 6 – Soil + Dandelion samples

Table 6

Mite chemical “baits”• Scientists have developed a new bait that may help

control varroa mites, the top pest of honey bees.  • the mites encounter a more heady bouquet of honey

bee odors that lure the parasites away from their intended hosts and onto the sticky boards, where they starve.

• In preliminary tests, 35 to 50 percent of mites dropped off the bees when exposed to the attractants. Free-roving mites found the semiochemicals even more attractive, according to Teal. http://www.sciencedaily.com/releases/2009/07/090705145109.htm

Survivorship of bees being fed HFCS feed vs Sucrose

High Fructose Corn Syrup• Although small backyard beekeepers

traditionally feed bees a mixture of sugar and water when colonies need extra food, commercial beekeepers largely use high fructose corn syrup. 

• HF corn syrup is cheap and easy to get in the U.S... but some scientists think feeding bees corn syrup could be one cause of colony collapse disorder.  

Hydroxymethylfurfural (HMF)• Research in the Journal of Agricultural and

Food Chemistry reports conditions, including heat, where potentially dangerous levels of hydroxymethylfurfural (HMF), a toxic substance, form in high-fructose corn syrup.

• This may suggest soft drinks + other human foods with high-fructose corn syrup have HMF. http://www.sciencedaily.com/releases/2009/08/090826110118.htm

Discussion• Bees exposed to pesticides at fields –

• A single seed with 0.5 mg/kernal Neonicotinoid has enough toxin to kill 80,000 bees.

• Talc residues are extremely high in Neonicotinoid pesticides

• Neonicotinoid pesticides are found in pollen + plant fluids

• Soil have residues even after 2 years

• Bees forage 50% of their pollen from corn• Pollen in healthy hives have <1/3 pesticide levels

The Literature on Neonicotinoids:• Neonicotinoid Pesticides in leaf droplets at

10-199 mg/l results in paralysis + death

• Delays in worker bee development

• High humidity may be required to kill bees (even at 100 ng CL / bee)

• Corn pollen 10x more toxic than Canola

• Nurse bees eat 65 mg pollen in 10 days which might result in 50% of the LD50 dose

• Fungicide Propicozole – synergistic toxicity

• Translocation of Neonicotinoid Insecticides From Coated Seeds to Seedling Guttation Drops: A Novel Way of Intoxication for Bees

• Guttation is when xylem fluids are released at leaf margins to attract ants. Leaf guttation drops from corn plants germinated from neonicotinoid-coated seeds contained amounts of insecticide constantly higher than 10 mg/l, with maxima up to 100 mg/l for thiamethoxam and clothianidin, and up to 200 mg/l for imidacloprid.

• http://esa.publisher.ingentaconnect.com/content/esa/jee/2009/00000102/00000005/art00011

• The Obsession With Lawns, a magazine article argues lawn care is harming is the bee population – which begs the question, where have all the bees gone? http://www.lowdensitylifestyle.com/FREE,%20flexibility,%20fluidity/colony-collapse-disorder/