Honeybees abandoning hives and dying due to #insecticide use, research finds | Environment | theguardian.com
▻http://www.theguardian.com/environment/2014/may/09/honeybees-dying-insecticide-harvard-study
Previously, scientists had suggested that neonicotinoids can lead to CCD by damaging the immune systems of bees, making them more vulnerable to parasites and disease. However, the new research undermines this theory by finding that all the colonies had near-identical levels of pathogen infestation.
“It is striking and perplexing to observe the empty neonicotinoid-treated colonies because honey bees normally do not abandon their hives during the winter,” the scientists wrote. “This observation may suggest the impairment of honey bee neurological functions, specifically memory, cognition, or behaviour, as the results from the chronic sub-lethal neonicotinoid exposure.” Earlier research showed neonicotinoid exposure can damage the renowned ability of bees to navigate home.
The new research follows similar previous work by the same group and comparison of the two studies shows that cold winters appear to exacerbate the effects of neonicotinoids on the bees. In the cold winter of 2010-11, 94% of the insecticide-exposed colonies suffered CCD compared to 50% in the new study.
“Sudden deaths of entire honey bee colonies is a persistent concern in North America,” said Paul de Zylva, Friends of the Earth’s senior nature campaigner. “Comprehensive research into the role pesticides play in bee decline is urgently required – including how they may compound other pressures, such as a lack of food and loss of habitat.” Lu agreed: “Future research could help elucidate the biological mechanism that is responsible for linking sub-lethal neonicotinoid exposures to CCD. Hopefully we can reverse the continuing trend of honeybee loss.”
In April, a landmark European study revealed the UK is suffering one of the worst rates of honeybee colony deaths in Europe. “The UK government [which opposed the EU’s neonicotinoid ban] has accepted the need for a national action plan to reverse bee and pollinator decline,” said de Zylva. “But its draft plan is dangerously complacent on pesticides, placing far too much trust in chemical firms and flawed procedures.”
▻http://www.bulletinofinsectology.org/pdfarticles/vol67-2014-125-130lu.pdf