Jamison Scholer July 2012 University of Minnesota Department of Entomology

1. Does imidacloprid and clothianidin reduce bumble bee colony health at residue levels found in landscape plants? Jamison Scholer July 2012 University of Minnesota Department of Entomology

2. Beekeepers • Petition for clothianidin to be withdrawn from sale • Registration was based on a Bayer study that was later found by beekeepers to be deficient and later EPA agreed (Feldman et al. 2010). • Insecticide seed coating dust extremely toxic to bees, new studies with clear evidence (Krupke et al. 2012, Tapparo et al. 2012, Marzaro et al. 2011). • Insecticide use contributes to weakened immune systemincreased susceptibility to pathogens. (Alaux 2010, Hawthorne & Dively 2011, Pettis et al. 2012). lovethehoneybees.blogspot.com

3. Neonicotinoids: Trade offs Advantages: • Neonicotinoids most often applied to the soil and are • translocated through the entire plant • Variety of application methods: soil drench, irrigation, • seed treatment, tree injection • Safer to mammals and birds (selective-binding to insects) Disadvantages: • Neonicotinoids most often applied to the soil and are • translocated to pollen and nectar • Harmful against all beneficial insects eating pollen, nectar • Long lasting residual effects in pollen, nectar, leaves, soil • Bayer argues 20 ppb imidacloprid will not affect • mortality, but will affect behavior.

4. Neonicotinoid: Use in Minnesota 2009 Active Ingredient in (lbs) Minnesota Department of Agriculture

5. Neonicotinoid: Products

6. Neonicotinoids: Persistence in the environment

7. Neonicotinoid: Toxicity to bees Mode of Action: Over stimulates nicotine receptors in central nervous system zmescience.com *Lethal dose to 50 percent of population

8. Neonicotinoids: imidacloprid residue levels

9. Experimental hypothesis Imidacloprid and clothianidin used at landscape rates will negatively affect colony health. Objectives Determine the effects of landscape rate use of imidacloprid and clothianidin on Bombus impatiens colony health. • Treat colonies with a range of imidacloprid and clothianidin doses for a summer (11 weeks). • Determine the effect of dose on colony health.

10. Methods: Experimental design • 5 treatments • (0, 10, 20, 50, 100 ppb) • 4 colonies / treatment • Repeat experiment 2 times • imidacloprid Fall 2011 • clothianidn Spring 2012 • 40 colonies / insecticide

11. Methods: Parameters measured • Bimonthly (3 times/experiment) • Colony weight • Biweekly • Individual worker weights (20 workers per colony) • Number of bees dead in flight box (separated by caste) • Weekly • Pictures of colony box looking at: • Number of brood cells • Number of bees • Number of honey pots • Number of empty cells • Queen status (dead or alive) • 48 hour • Sugar syrup consumption

12. Methods: Neonicotinoid treatments • Treated syrup: Add neonicotinyl • insecticide to 50% sugar syrup • Five Treatments (ppb) 0 ppb = control 10 ppb = pollen from seed treatments 20 ppb = NOEC from Bayer, but affects behavior 50 ppb = Field pumpkin study 100 ppb = Lower level found in landscape plants • EPA LD50 for imidacloprid 4-40 ng/bee • = 40-400 ppb • LD50 for clothianidin 3.8 ng/bee • = 38 ppb

13. Annual life cycle: Bombus impatiens Queen starts colony in May Winter New queen + drone production in late summer Mating in fall

14. Bumble bee colonies in the greenhouse

15. Bumble bee colonies with flight box Brood box Flight box

16. 48 hr measurement of sugar syrup consumption from feeders

17. Sugar syrup consumption (Week 8) ANOVA: F = 22.2, df = 4, 35, p = 0.0001 ANOVA: F = 34.5, df = 4, 28, p = 0.0001 a A b B BC c c C C c

18. Queen mortality (week 8) 8/8 7/8 6/9 5/8 3/8 2/9 1/8

19. Measurement of bee and colony weight

20. Mean individual bee weight (week 8) ANOVA: F = 2.8, df = 4, 26, p = 0.05 ANOVA: F = 1.7, df = 4, 24, p = 0.18 a a a A a AB AB a AB B

21. Mean colony weight (final) ANOVA: F = 16.2, df = 4, 35, p = 0.0001 ANOVA: F = 16.1, df = 4, 37, p = 0.0001 a A a B BC C C b b b

22. Measuring nest development

23. Mean number of honey pots (final) ANOVA: F = 5.3, df = 4, 35, p = 0.0020 ANOVA: F = 12.7, df = 4, 37, p = 0.0001 a ab A AB bc bc AB B c B

24. Measuring number of bees produced • Bees collected • Flight box (Biweekly) • Colony dissection (End of experiment) Males Females Queens

25. Total number adult bees produced (final) ANOVA: F = 4.6, df = 4, 35, p< 0.0042 ANOVA: F = 4.6, df = 4, 35, p< 0.0042 A a ab AB ab B AB b b B

26. Annual life cycle: Bombus impatiens Birkhäuser (2002), Fisher (1992)

27. Summary of preliminary results

28. Sugar Consumption Colony weight Queen mortality Number of honey pots

29. Experimental hypothesis Imidacloprid and clothianidin used in landscape rates will negatively affect colony health. Objectives Determine the effects of landscape rate use of imidacloprid and clothianidin on Bombus impatiens colony health. • Treat colonies with a range of imidacloprid and clothianidin doses for a summer (11 weeks). • Determine the effect of dose on colony health.

30. References Alaux, C., Brunet, J.L., Dussaubat, C., Mondet, F., Tchamitchan, S., Cousin, M., Brillard, J., Baldy, A., Belzunces, L.P., Conte, Y.L., 2010. Interactions between Nosema microspores and a neonicotinoid weaken honeybees (Apis mellifera). Environmental Microbiology. 12, 774-782. Cameron, S.A., Loziera, J.D., Strange, J.P., Koch, J.B., Cordesa, N.L., Solter, F., Griswold. T.L., 2010. Patterns of widespread decline in North American bumble bees. PNAS. Early Edition. Cordes, N., Huang, W.F., Strange, J.P., 2012. Interspecific geographic distribution and variation of the pathogensNosemabombi and Crithidia species in United States bumble bee populations. Journal of Invertebrate Pathology. 109, 209-216. Feldman, 2010. Correspondence with the Environmental Protection Agency Fisher, R.M., 1992. Sex ratios in bumble bee social parasites – support for queen-worker conflict theory? (Hymenoptera, Apidae). Sociobiology 20: 205–217. Grixti, J.C., Wong, L.T., Cameron, S.A., Favret, C., 2009. Decline of bumble bees (Bombus) in the North American Midwest. Biological Conservation. 142, 75-84. Hawthorne, D.D., Dively, G.P., 2011. Killing them with kindness? In-hive medication may inhibit xenobiotic efflux transporters and endanger honey. PLOS ONE. 6(11). Hoffmann, E.J., Castle, S.J., 2012. Imidacloprid in Melon Guttation Fluid: A Potential Mode of Exposure for Pest and Beneficial Organisms. Economic Entomology. 105, 67-71. Marzaro, M. Vivan, L., Targa, A., Mazzon, L., Mori, N., Greatti, M., Petrucco, T.E., DiBernardo, A., Giorio, C., Marton, D., Tapparo, A., Girolami, V., 2011. Lethal aerial powdering of honey bees with neonicotinoids from fragments of maize seed coat. Bulletin of Insectology. 64, 119-126. Mommaerts, V., Reynders, S., Boulet, J., Besard, L., Sterk, G., Smagghe, S.G., 2009. Risk assessment for side-effects of neonicotinoids against bumble bees with and without impairing foraging behavior. Ecotoxicology. 19, 207-215.

31. References Tapparo, A., Marton, D., Giorio, C., Zanella, A., Solda, L., Marzaro, M., Vivan, L., Girolami, V., 2012. Assessment of the Environmental Exposure of Honeybees to Particulate Matter Containing Neonicotinoids Insecticides Coming from Corn Coated Seeds. Environ. Sci. Technol. 46, 2592-2599. Whitehorn, P.R., O’Connor, S., Wackers, F.L., Goulson, D., 2012. Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science. 336, 351-352.

32. Questions? Acknowledgments Dr. Vera Krischik (Advisor) Karine Pouliquen (Lab supervisor) Judy Wu Dr. Ian Burns Undergraduate help including Tyler Obermoller Rafael Boulton Kristen Waurio Funding Source USDA Sustainable Agriculture Research and Education Legislative-Citizen Commission on Minnesota Resources