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 )
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 = 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 = 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 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 pesticides Levels 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.
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. 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.
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 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.
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? Obsession With Lawns