Widely used insecticides interfere with the homing instincts of bees, international researchers suggested Thursday, linking a class of agricultural pesticides to the growing threat to beehives known as colony collapse disorder. Explanations have ranged from poor nutrition to diseases to mite pests, which have devastated wild honeybees. Also mentioned in the new study, which looked at both honeybees and bumblebees, are pesticides, including the "neonicotinoid" insecticides that are among the most widely used agricultural pesticides worldwide.Colony Collapse Disorder has dramatically affected the populations of Honey Bees in the United States. I rarely see them anymore; they used to be common. However, there have been numerous claims for the cause in the past, including cell phones, and parasites turning them into zombies. I hope we solve this and find something we can do about it, but after many unproven claims, the standard of proof needs to be kept appropriately high.
In their study, Goulson and colleagues dosed some bumblebee hives with the insecticides, but not others. They placed the hives in enclosed fields where their bees could forage naturally. After six weeks, they found that the dosed hives were 8% to 12% smaller than the others and, more important, that they produced only 15% as many queen bees, an average of two compared with nearly 14 in undosed hives, important for the hive-producing future generations of bees.
"The bumblebee finding is really important" because reproduction is a key element in deciding whether or not to approve a particular insecticide, says entomologist Jeffery Pettis of the U.S. Department of Agriculture. The queen bees that survive the winter are the ones that must start a new hive the next year, so if fewer queens are produced that directly affects survival.