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As a service to bees and other pollinators, the Pollinator Partnership provides a synopsis and abstract from recent published research papers on our website, and it is updated periodically. Your suggestions are welcome; please send them to info@pollinator.org.

Updated May 25, 2012

By James E. Cresswell, Nicolas Desneux, and Dennis vanEngelsdorp in Pest Management Science, 68(6):819–827, June 2012.

Abstract: Honey bees are important pollinators of both crops and wild plants. Pesticide regimes that threaten their sustainability therefore should be assessed. As an example, we examine the evidence that the agricutral use of the neonicotinoid pesticides is a cause of the recently observed declines in honey bees. We aim to define exacting demographic conditions for a detrimental factor to precipitate a population decline and we employ Hill’s epidemiological ‘causality criteria’ as a structured process for making an expert judgement about the proposition that trace dietary neonicotinoids in nectar and pollen cause population declines in honey bees.

By Tjeerd Blacquière, Guy Smagghe, Cornelis A. M. Gestel, and Veerle Mommaerts in Ecotoxicology, 21(4):973–992, May 2012.


A common pesticide decreases foraging success and survival in honey bees.
By Mickaël Henry, Maxime Béguin, Fabrice Requier, Orianne Rollin, Jean-François Odoux, Pierrick Aupinel, Jean Aptel, Sylvie Tchamitchian, and Axel Decourtye in Science, 336(6079):348–350, April 2012.

Abstract: Nonlethal exposure of honey bees to thiamethoxam (neonicotinoid systemic pesticide) causes high mortality due to homing failure at levels that could put a colony at risk of collapse. Simulated exposure events on free-ranging foragers labeled with a radio-frequency identification tag suggest that homing is impaired by thiamethoxam intoxication. These experiments offer new insights into the consequences of common neonicotinoid pesticides used worldwide.

Do pathogen spillover, pesticide use, or habitat loss explain recent north american bumblebee declines? 
By Nora D. Szabo, Sheila R. Colla, David L. Wagner, Lawrence F. Gall, and Jeremy T. Kerr in Conservation Letters, April 2012.

Abstract: Several North American bumblebee species have recently undergone dramatic declines. The use of managed, pathogen-carrying bumblebees for pollination of greenhouse crops began shortly before these declines, and wild bumblebees near greenhouses now have high pathogen loads. This has led to speculation that pathogen spillover from commercial bumblebees caused declines of these species. We test this hypothesis using a large dataset of bumblebee occurrence records and agricultural census data. We find support for the pathogen spillover hypothesis for two species but no evidence that pathogen spillover caused the near disappearance of the previously widespread Bombus affinis. Furthermore, we show that pesticide use and habitat loss are unlikely to be major causes of decline for any of the Bombus species examined. Collectively, our analyses underscore that there remains an urgent need to identify causes of pollinator population losses.

Neonicotinoid pesticide reduces bumble bee colony growth and queen production.
By Penelope R. Whitehorn, Stephanie O’Connor, Felix L. Wackers, and Dave Goulson in Science, 336(6079):351–352, April 2012.


By Julie Aufauvre, David G. Biron, Cyril Vidau, Régis Fontbonne, Mathieu Roudel, Marie Diogon, Bernard Viguès, Luc P. Belzunces, Frédéric Delbac, and Nicolas Blot in Scientific Reports, 2, March 2012.


By Christian H. Krupke, Greg J. Hunt, Brian D. Eitzer, Gladys Andino, and Krispn Given in PLoS ONE, 7(1):e29268+, January 2012.


By Jeffery S. Pettis, Dennis vanEngelsdorp, Josephine Johnson, and Galen Dively in Naturwissenschaften, 99(2):153–158, January 2012.


Translocation of neonicotinoid insecticides from coated seeds to seedling guttation drops: A novel way of intoxication for bees.
By V. Girolami, L. Mazzon, A. Squartini, N. Mori, M. Marzaro, A. Di Bernardo, M. Greatti, C. Giorio, and A. Tapparo in Journal of Economic Entomology, 102(5):1808–1815, September 2009.

Abstract: The death of honey bees, Apis mellifera L., and the consequent colony collapse disorder causes major losses in agriculture and plant pollination worldwide. The phenomenon showed increasing rates in the past years, although its causes are still awaiting a clear answer. Although neonicotinoid systemic insecticides used for seed coating of agricultural crops were suspected as possible reason, studies so far have not shown the existence of unquestionable sources capable of delivering directly intoxicating doses in the fields. Guttation is a natural plant phenomenon causing the excretion of xylem fluid at leaf margins. Here, we show that leaf guttation drops of all the corn plants germinated from neonicotinoid-coated seeds contained amounts of insecticide constantly higher than 10 mg/1, with maxima up to 100 mg/1 for thiamethoxam and clothianidin, and up to 200 mg/1 for imidacloprid. The concentration of neonicotinoids in guttation drops can be near those of active ingredients commonly applied in field sprays for pest control, or even higher. When bees consume guttation drops, collected from plants grown from neonicotinoid-coated seeds, they encounter death within few minutes.

Quantification of imidacloprid uptake in maize crops.
By J. M. Bonmatin, P. A. Marchand, R. Charvet, I. Moineau, E. R. Bengsch, and M. E. Colin in J. Agric. Food Chem., 53(13):5336–5341, June 2005.

Abstract: The systemic imidacloprid is one of the most used insecticides in the world for field and horticultural crops. This neurotoxicant is often used as seed-dressing, especially for maize, sunflower, and rape. Using a LC/MS/MS technique (LOQ = 1 μg/kg and LOD = 0.1 μg/kg), the presence of imidacloprid has been measured in maize from field samples at the time of pollen shed, from less than 0.1 μg/kg up to 33.6 μg/kg. Numerous random samples were collected throughout France from 2000 to 2003. The average levels of imidacloprid measured are 4.1 μg/kg in stems and leaves, 6.6 μg/kg in male flowers (panicles), and 2.1 μg/kg in pollen. These values are similar to those found previously in sunflower and rape. These results permit evaluation of the risk to honeybees by using the PEC/PNEC ratios (probable exposition concentrations/predicted no effect concentration). PEC/PNEC risk ratios were determined and ranged between 500 and 600 for honeybees foraging on maize treated with imidacloprid by seed dressing. Such a high risk factor can be related to one of the main causes of honeybee colony losses.

By Agnes Rortais, Gerard Arnold, Marie-Pierre Halm, and Frederique Touffet-Briens in Apidologie, 36(1):71–83, January 2005.



By Severine Suchail, David Guez, and Luc P. Belzunces in Environmental Toxicology and Chemistry, 20(11):2482–2486, November 2001.

Abstract: Imidacloprid is a systemic nitroguanidine insecticide that belongs to theneonicotinoid family. As an agonist of the acetylcholine receptor, it attacks the insect nervous system and is extremely effective against various sucking and mining pests. Oral acute and chronic toxicity of imidacloprid and its main metabolites (5-hydroxyimidacloprid, 4,5-dihydroxyimidacloprid, desnitroimidacloprid, 6-chloronicotinic acid, olefin, and urea derivative) were investigated in Apis mellifera. Acute intoxication by imidacloprid or its metabolites resulted in the rapid appearance of neurotoxicity symptoms, such as hyperresponsiveness, hyperactivity, and trembling and led to hyporesponsiveness and hypoactivity. For acute toxicity tests, bees were treated with doses of toxic compounds.

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