Honeybees

Changes in arable farming practices have been identified as important factors in the decline of wildlife. Significant declines in the brown hare have been recorded, associated with changes in the availability of high quality food at certain times of year. Declines in the Pipistrelle Bat are in part likely to have resulted from lower abundance of insect prey in farmland. Information on the decline of arthropods in farmland habitats has been published by the Game Conservancy Trust’s Sussex Study In the Sussex study area, between 1972 and 1990, arthropods have declined by 4.2% per annum (excluding springtails and mites), with many groups of beneficial insects, such as aphid predators and game bird food items, declining at faster rates. Bee species are particularly threatened. A range of cornfield weeds, such as corn buttercup and shepherd’s-needle, have declined markedly this century, to the extent that some species are now extinct in the UK. These annual flowers are dependent on the arable ecosystem, which is characterised by regular soil cultivation. Declines in farmland birds have been identified for a number of species characteristic of arable and mixed farmland. These birds feed on seeds, invertebrates or both, sometimes at different times of year.

Greenpeace Europe has called for the urgent elimination of all bee-harming pesticides from agriculture in Europe. In a statement accompanying the study ‘Bees in decline – a review of factors that put pollinators and agriculture in Europe at risk’, published on 9 April, the organisation argues that a total ban would “be a crucial and effective first step” to protect the health of bee populations and to safeguard their pollination value. “Science is clear: the negative impacts of bee-harming pesticides by far exceed any presumed benefits,” Matthias Wüthrich, ecological farming campaigner and European bees project leader at Greenpeace Switzerland, said. “EU countries simply can’t wait any longer and must take immediate action with a complete and immediate ban on these bee-killers,” he added.

De insecticiden die verantwoordelijk worden gehouden voor de bijensterfte blijken ook sterfte bij vogels te veroorzaken. De American Bird Conservancy (ABC) concludeerde in een dik rapport dat deze zeer effectieve insectendodende gifstoffen aantoonbare invloed hebben op vogels. Deze stoffen worden ook verantwoordelijk gehouden voor de bijensterfte die in alle delen van de wereld gaande is. In ons land wordt op grote schaal gebruik gemaakt van dit gif. Heel jammer dat een voorstel van de Europese Commissie voor een verbod recent verworpen is. De bioloog Arnold van Vliet op Youtube: http://www.youtube.com/arnoldvanvliet

At the request of the Dutch Nature and Environment Foundation, two scientists of the Dutch Centre for Agriculture and Environment (CLM) conducted an independent analysis of confidential studies on potential risks of the pesticide imidacloprid to bees through two visits to Bayer's 'reading room'. Their conclusions were as follows. The unpublished studies provide insufficient information on long-term (sub) lethal effects, combination toxicology or synergy between factors such as imidacloprid exposure and the impact of diseases and scarcity of alternative food sources. Sublethal effects mentioned in the studies were brushed aside by the Dutch regulators. The confidential studies worked with a limited number of crops and doses, and extrapolated data were used on other crops for which no residue measurements in pollen and nectar were available. The regulatory authority assessed the risks to bees on the basis of Good Agricultural Practice (GAP) and strict observance of the label text. This is, unfortunately, not in line with common practice, causing greater emissions, exposures and risks. The regulators applied little or no safety margins in the assessment of the data, rarely adopted worst-case scenarios and allowed the use of largely extrapolated data. Degradation models were frequently used instead of direct measurements. Since the basis for risk assessment was very thin, it was impossible to determine whether or not bees were at risk through the use of imidacloprid. There were so many uncertainties, that risks can not be ruled out. This is consistent with the conclusions of EFSA.

The Government must introduce a precautionary moratorium on three pesticides linked to the decline of pollinators - imidacloprid, clothianidin and TMX – that suspends their use on flowering crops attractive to pollinators, Parliament’s cross-party green watchdog has said. Environmental Audit Committee Chair, Joan Walley MP, commented: “Defra seems to be taking an extraordinarily complacent approach to protecting bees given the vital free service that pollinators provide to our economy. If farmers had to pollinate fruit and vegetables without the help of insects it would cost hundreds of millions of pounds and we would all be stung by rising food prices. Defra Ministers have refused to back EU efforts to protect pollinators and can’t even come up with a convincing plan to encourage bee-friendly farming in the UK.” Two-thirds of wild insect pollinator species - such as bumblebees, hoverflies, butterflies, carrion flies, beetles, midges and moths - have suffered population declines in the UK. Managed honeybees have also experienced unusually high mortality rates, decreased fertility, increased susceptibility to disease and the loss of hives. Similar trends have been observed in the US and other European countries.

Pesticides are important agricultural tools often used in combination to avoid resistance in target pest species, but there is growing concern that their widespread use contributes to the decline of pollinator populations. Pollinators perform sophisticated behaviours while foraging that require them to learn and remember floral traits associated with food, but we know relatively little about the way that combined exposure to multiple pesticides affects neural function and behaviour. The experiments reported here show that prolonged exposure to field-realistic concentrations of the neonicotinoid imidacloprid and the organophosphate acetylcholinesterase inhibitor coumaphos and their combination impairs olfactory learning and memory formation in the honeybee. Using a method for classical conditioning of proboscis extension, honeybees were trained in either a massed or spaced conditioning protocol to examine how these pesticides affected performance during learning and short- and long-term memory tasks. We found that bees exposed to imidacloprid, coumaphos, or a combination of these compounds, were less likely to express conditioned proboscis extension towards an odor associated with reward. Bees exposed to imidacloprid were less likely to form a long-term memory, whereas bees exposed to coumaphos were only less likely to respond during the short-term memory test after massed conditioning. Imidacloprid, coumaphos and a combination of the two compounds impaired the beesʼ ability to differentiate the conditioned odour from a novel odour during the memory test. Our results demonstrate that exposure to sublethal doses of combined cholinergic pesticides significantly impairs important behaviours involved in foraging, implying that pollinator population decline could be the result of a failure of neural function of bees exposed to pesticides in agricultural landscapes.

The European Commission said, on 19 March, that it would refer its proposal for a ban on the use of three neonicotinoid insecticides (clothianidin, imidacloprid and thiametoxam) on crops attractive to honeybees to the Appeal Committee after an inconclusive vote in the Standing Committee on the Food Chain and Animal Health last week (see Europolitics4608). Announcing the Commission’s decision at the Agriculture Council, Health and Consumer Policy Commissioner Tonio Borg pledged to do his utmost to “find solutions that command the widest possible support”. “The health of our bees is of paramount importance – we have a duty to take proportionate yet decisive action to protect them wherever appropriate,” he added, reiterating his determination to receive qualified majority support at the Appeal Committee for his proposal. “The Commission still envisages to have measures in place by 1 July 2013,” Borg’s services said in a separate statement. No date of the vote in the Appeal Committee was given at this stage.