Unintended Consequences of Seed-Applied Insecticides

Bee-collected pollen analysis: Pesticides• Half of the pollen samples analyzed to date containedthiamethoxam, clothianidin or both• All contained fungicides, applied aerially during pollen shed• Fungicides in this family synergize neonicotinoid toxicity inhoneybeesHIVEIDMeanconcentrations(SE),ppb(#sampleswithdetection)Thiamethoxam(Cruiser)Clothianidin(Poncho)Untreated1 ND 4.0(1/5)Untreated2 ND 4.9(±2.3)(4/5)Propiconazole(Tilt)17.5(±6.0)(5/5)10.8(±1.9)(5/5)Treated1 ND ND 9.7(±3.6)(5/5)Treated2 2.18(3/5)27.8(±15.4)(4/5)7.5(±1.2)(5/5)Azoxystrobin(Quadris)29.2(±13.5)(5/5)15.6(±4.2)(5/5)19.7(±11.6)(5/5)12.1(±4.7)(5/5)Worker longevity experiments• Goal: Quantify effects of living near treated/untreatedcorn upon worker longevity• Placed 4 hives at each location (treatment):1) Non-agricultural area (Gravel pit)2) Adjacent to neonicotinoid-treated corn (TPAC)3) Adjacent to untreated corn (TPAC)• Two hives/location with pollen traps installed tosample pollen weekly• Two hives/location with marked workers introduced at2 intervals: 1) planting time, 2) at corn silking• Correlate worker longevity with pollen entering hiveat various periods through seasonColony-level effectsWorker longevity experiments• Pollen is primary proteinsource for bees• After eclosion, youngworkers feed on storedpollen - consumeapproximately 65 mgover 10-d period• Effects of consumingcontaminated pollen?Stored pollen• Introduced 250 paintmarked,24-h oldworkers to each hive• Each frame removedand photographed• Photos 24-h afterintroduction(baseline), then 7, 14,21 days afterintroduction• Conductedimmediately afterplanting and duringcorn pollen shedResults: Forager longevityduring pollen shed• No rapid intial mortality – mortality curves were initiallysimilar• Possible reduced lifespan in/near cornfields?• May have ended prematurely...revisit in 2012Seed treatments are labeled for control of manypests…ProportionsurvivingCorn rootwormBlack cutwormSeedcorn maggotWhite grubWirewormAndmany,manymore!5