http://www.ibtimes.com/colony-collapse-disorder-highly-likely-caused-insecticides-harsh-winters-increase-honey-1582734
Researchers have again linked the unexplained decline in honey-bee populations worldwide,a phenomenon known as colony-collapse disorder (CCD),to a certain class of insecticides called neonicotinoids. Furthermore, new research found that colder winters have aggravated the condition.
In a study released Friday in the Bulletin of Insectology,scientists from Harvard University revealed that exposure to two neonicotinoids,the most widely used class of insecticides in the world,was responsible for half of the colonies they studied dying.
"We demonstrated again in this study that neonicotinoids are highly likely to be responsible for triggering [colony-collapse disorder] in honey-bee hives that were healthy prior to the arrival of winter," Chensheng Lu,an associate professor of environmental exposure biology at the Harvard School of Public Health and lead author of the study,said in a statement.
The new study builds on the university’s previous work that discovered a link between just one kind of neonicotinoid,imidacloprid,and colony collapse disorder. This time around,researchers focused on imidacloprid as well as clothianidin and found that both chemicals had the same effect on honey bees –causing them to abandon their hives in winter and die.