* * On Tue, Jan 8, 2013 at 6:51 AM, Ghislain De Roeck <[log in to unmask]> wrote: > Against the current, I know ... > http://www.boerenlandvogels.nl/sites/default/files/JEIT-D-12-00001_0.pdf Well not that much I guess ... From Eric Mussen's newsletter 'from the U.C. Apiaries University of California' Nov/Dec 2012 *Nosema/Fipronil Synergy* Most beekeepers are familiar with results of studies conducted at the USDA Beltsville Bee Lab that demonstrated a synergy between imidacloprid and Nosema ceranae infections. The infections became worse when the bees had been exposed to the neonicotinoid. A group of researchers in France conducted a similar experiment and obtained similar results with fipronil and thiacloprid and Nosema ceranae. The French researchers expanded their studies on the insecticide fipronil, a phenylpyrazole with the chemical name (5-amino-1-(2,6- dichloro-á-á-á-trifluoro-p-tolyl)-4- trifluoromethylsulfinylpyrazole-3- carbonitrile). In this case, they decided to see if they would induce synergism when the treatments were administered in four different regimes. In one approach, newly emerged bees were inoculated with Nosema spores and exposed during the first week to a sublethal dose of fipronil, right after emerging. In the second case, the bees were exposed to the fipronil for a week at the beginning, but the microbe was inoculated a week later. In the third situation, bees were inoculated with Nosema ceranae right after emerging and the week-long application of fipronil was applied a week later. Finally, the bees were treated with both stressors at the same time, after being caged for one week. It turned out that over the 23 days of the trials, being exposed to sublethal levels of fipronil alone, and being inoculated with Nosema spores alone, did not change mortality very much from that of the controls - between 75 and 80 percent survival. However, when the toxicant and microbe were combined, the survivorship dropped to between 23 and 39 percent. The only difference was in timing of the mortality. If either the application of toxicant or inoculation with the microbe was delayed a week, then the mortality was delayed but showed a much steeper loss with time. The authors of the paper suspected that the synergism could go one of two ways. The toxicant could make the bees more susceptible to infections or the exposure to sublethal doses might induce stress resistance to infections. In this case, as in the case of mosquitoes and either entomopathic fungus Beauveria bassiana or Metarhizium anisopliae and permethrin, the combination was particularly hard on the insect. With mosquitoes, that can be good. With bees, that isn't so good. If you wish to examine this study, it should be available on the Internet. The title is: "Parasite-insecticide Interactions: A Case Study for Nosema ceranae and Fipronil Synergy on Honeybee." Authors are Julie Aufauvre, et al. URL is: doi: 10.1038/ srep00326. The Journal is Scientific Reports 2: 326. > > *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html Guidelines for posting to BEE-L can be found at: http://honeybeeworld.com/bee-l/guidelines.htm