With our schools all on spring break here, I’ve had a revolving door of bored children passing through the house all week so I am a bit behind in posts that I’d planned to get done. Maybe it has all worked out for the best as articles have piled up, I now have three slightly conflicting and very interesting news stories about pesticides and the potential harm they cause (or don’t?) our bee colonies…
Pesticide makes bees forget the scent for food, new study finds
“Neocotinoids block part of brain bees use for learning, leaving them unable to make link between floral scents and nectar.”
Bees exposed to widely-used pesticides were slow to make or forgot completely the link between floral scents and food. Photograph: C.N.Connolly/PA
The Guardian – “Widely used pesticides have been found in new research to block a part of the brain that bees use for learning, rendering some of them unable to perform the essential task of associating scents with food. Bees exposed to two kinds of pesticide were slower to learn or completely forgot links between floral scents and nectar.
These effects could make it harder for bees to forage among flowers for food, thereby threatening their survival and reducing the pollination of crops and wild plants.
The findings add to existing research that neonicotinoid pesticides are contributing to the decline in bee populations.
It has also been revealed that a separate government field study on the impact of the pesticides on bees was seriously compromised by contamination because the chemicals are so widespread in the environment.
The government put the field study at the heart of the UK’s resistance to a Europe-wide ban on the controversial pesticides earlier this month. The UK was one of nine out of 27 member states that opposed suspending some uses of the insecticides across the EU, after environment secretary Owen Paterson said, “I have asked the EC to wait for the results of our field trials, rather than rushing to a decision”. On Wednesday, his department said more field research was needed.
The new findings on the effect of pesticides on bee brains showed that within 20 minutes of exposure to neonicotinoids the neurons in the major learning centre of the brain stopped firing. Christopher Connolly at the University of Dundee, who led the peer-reviewed work published in the online journal Nature Communications, said it was the first to show the pesticides had a direct impact on pollinator brain physiology.
A parallel peer-reviewed study on the behaviour of bees subjected to the same insecticides found the bees were slower to learn or completely forgot important associations between floral scent and food rewards. “Disruption in this important function has profound implications for honeybee colony survival, because bees that cannot learn will not be able to find food,” said Dr Geraldine Wright, at Newcastle University, who led the work.
The scientists who carried out the separate field study for the Department for Environment Food and Rural Affairs admitted it was “not a statistically robust study” because of the contamination issues. The trial results (pdf), which have not been peer-reviewed, showed that 20 hives of bumblebees meant to act as pesticide-free controls in the experiments were significantly contaminated owing to the widespread presence of the chemicals in the environment. Neonicotinoids are near ubiquitous in modern agriculture and earn billions a year for their manufacturers. But a series of high-profile scientific studies in the last year has increasingly linked them to harmful effects in bees. Declines in bees and other pollinators, which fertilise three-quarters of the world’s food crops, have been linked to habitat loss and disease as well as pesticides.
Julian Little of Bayer, which makes one of the neonicotinoids tested in the government study, said: “We welcome field studies and once again, when such studies are carried out, there does not appear to be a link between neonicotinoid seed treatment use and poor bee health.” Full Article
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Neonicotinoids pose ‘low’ risk to bees, Defra studies show
“The two pieces of research, including a field trial from the Food and Environment Research Agency (Fera), contradict the findings of an EU risk assessment and are likely to reinforce the UK’s opposition to a proposed EU ban.”
DEFRA has published two pieces of research suggesting the risk of neonicotinoids seed treatments to bee populations in the field is low.
The Farmer’s Guardian – “The European Commission is planning to suspend the use of three neonicotinoid products - imidacloprid, thiamethoxam and clothianidin – for two years from as soon as this July.
The proposal is based on the findings of a risk assessment by the European Food Safety Agency (Efsa), which found the chemicals, which are used to treat seeds prior to sowing to protect against insects like aphids, pose a ‘high risk’ to honey bees from crops producing nectar and pollen.
