Study points to stew of pesticides as possible cause of colony collapse disorder among bees

Results from a two-year study have focused more attention on one possible cause of the mysterious colony collapse disorder affecting beehives across the country: pesticides. "Christopher Mullin of Pennsylvania State University in University Park and his colleagues describe widespread pesticide tainting in 749 samples of bee-dom, some of those chemicals at levels that would be toxic if they occurred alone," Janet Raloff of Science News reports. "Except that most bees aren’t exposed to just a single pesticide."

The researchers found eight different pesticides on average in the 259 beeswax samples, and seven chemicals on average in the 350 pollen samples retrieved from hives. The 140 bees sampled average about two chemicals per bee, Raloff reports, although one pitiful bee contained 25 different pesticides. The researchers suggested bees were less contaminated because many died before ever making it back to the hive to be chosen in the study.

The researchers analyzed 140 bees from both healthy hives and those affected by colony collapse disorder. They also analyzed all aspects of the hives, as well, and found that just one of the wax samples, three pollen samples and 12 bee samples were free of detectable pesticides. "The biological impacts of these materials at their dietary levels on other honey bee larvae or adults remains to be determined," the researchers write. Mortality may not be the chief concern, as previous research found pesticides impacted honey bee learning, immune system functioning, and synergism of insecticide toxicity by fungicides. (Read more)