New pesticides linked to bee population collapse
"Worldwide declines in bee colonies, threatening much of global agriculture, may be caused by a new generation of nerve-agent pesticides, two new scientific studies strongly suggest. The findings place a massive question mark over the increasingly controversial compounds, now the fastest growing family of insecticides in the world."
more on pesticides link to mass bee collapse
Pesticides suspected in mass die-off of bees
Two studies show that a class of chemicals known as neonicotinoids created disorientation among bees and caused colonies to lose weight, which may have contributed to a mysterious die-off.
March 29, 2012, 5:13 p.m.
"In Scotland, Goulson and his colleagues brought colonies of bumblebees indoors, feeding some a diet of pollen and nectar tainted with neonicotinoids and giving others food without the chemicals. Then they let both groups of bees out in an enclosed field site and let them forage for six weeks.
By the end of the study period, the bees that ate the insecticide produced 85% fewer queens per colony, on average. The queens lay the eggs that produce the members of the colony for the next year.
"If that went on for years, the consequences could be pretty dramatic," Goulson said.
The colonies that were exposed to the pesticide also gained 8% to 12% less weight — including honey and beeswax — than the control colonies.
The second study, led by researchers from the French National Institute for Agricultural Research, or INRA, focused on honeybees, which have been victimized by colony collapse disorder throughout the Northern Hemisphere.
First they glued special radio frequency identification tags to the bees' thoraxes. Then they fed the bees sublethal doses of a neonicotinoid and monitored the insects as they attempted to return to the hive.
The research team discovered that the "intoxicated" bees were about twice as likely as unexposed bees to die because they couldn't find their way home. Computer simulations suggested that these no-shows could cause hive populations to crash in a matter of weeks, said study coauthor Mickael Henry, a researcher at INRA in Avignon.
The weakened colonies would be especially vulnerable to environmental stresses such as climate change or disease, he added."
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