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Since the mid-1960s, environmental toxicology focussed on the effects of bioaccumulation of organochlorine insecticides in organisms, and their consequences for populations of species in the wild. Prompted by the release of Silent Spring, scientists sifted focus to the ecological effects of pesticides, thus expanding the narrow field of pesticide toxicology that had been restricted to its effects on pests, weeds and pathogenic fungi since its beginnings. The ensuing decades will witness a tremendous gathering of data related to the toxic impacts that insecticides, herbicides and fungicides have on organisms and ecosystems. Despite these efforts, our understanding of the mechanisms of toxicity at different levels of biological organisation has not kept abreast with the overwhelming progress experienced in the development of new pesticides. While chemical companies introduced new plant protection products in the market at a staggering pace, environmental toxicology has trailed behind.

Researchers with the Canadian Pollination Initiative (NSERC-CANPOLIN) mined numerous insect collections in Canada and the United States looking for information on the distribution and abundance of 21 eastern species of bumble bees. "It is really difficult to know if a species is in trouble unless you have good historical data for comparison. This is the first time data gathered from historical collections has been used to assess the current status of Nearctic bees across their entire native range," says Sheila Colla, a recent PhD graduate from York University who led the study. The study was based on 44,797 bee specimens collected between 1864 and 2009. Researchers used both taxonomic and geographic data found in collection records to measure the persistence and relative abundance of each species across the full range of their distribution. Of the 11 species found to be in decline, four are deemed "vulnerable", six are considered "endangered" and one is "critically endangered".

Carabid beetles are important functional components of many terrestrial ecosystems. Here, we describe the first long-term, wide-scale and quantitative assessment of temporal changes in UK carabid communities, to inform nationwide management aimed at their conservation. Multivariate and mixed models were used to assess temporal trends over a 15-year period, across eleven sites in the UK Environmental Change Network. Sites covered pasture, field margins, chalk downland, woodland and hedgerows in the lowlands, moorland and pasture in the uplands, and grassland, heaths and bogs in montane locations. We found substantial overall declines in carabid biodiversity. Three-quarters of the species studied declined, half of which were estimated to be undergoing population reductions of > 30%, when averaged over 10-year periods. Declines of this magnitude are recognized to be of conservation concern. They are comparable to those reported for butterflies and moths and increase the evidence base showing that insects are undergoing serious and widespread biodiversity losses.

Retailers have clarified their stance on pesticide use after new research revealed a combination of two commonly used products harmed bumblebee populations. The Co-operative Group said imidacloprid was a neonicotinoid that was on its “prohibited list”, which applied to fresh and frozen produce sold in store and grown on its farms. Morrisons said it understood the importance of encouraging healthy bee populations in the UK and screened all pesticides used by its suppliers to ensure they did not have an adverse effect on bees. Tesco, meanwhile, said it did not use the two pesticides in combination on any “flowering crops” such as apples or pears in the UK. Sainsbury’s did not respond to specific questions over whether its suppliers were permitted to use the two pesticides mentioned in the study. A spokeswoman, however, said: “Our pesticide policy requires our suppliers to minimise their use of pesticides and employ Integrated Crop Management techniques.”

The purpose of the current study was to investigate the immunological impacts of chronic imidacloprid insecticide toxicity in broiler chickens and the protective effects of vitamin E and selenium. Broiler chicks (n=90) aged day old were randomly segregated into three groups of 30 chicks each and were kept in separate pens. Newcastle disease (ND) vaccine was given on day 7 and 28 of age. On day 8, chicks in group I were administered 5 mg/kg bw (1/20 LD50) imidacloprid orally. Chicks in group II were given imidacloprid 5 mg/kg bw orally plus a mixture of vitamin E and selenium ≅ 200 mg/kg diet, while group III was given distilled water (DW) orally and served as a control. The treatments were given daily based on weekly body weight till day 45. Antibody titration, serum total immunoglobulins, circulating immune complexes, cell-mediated immunity and histopathology of bursa of Fabricius and spleen were examined. Imidacloprid produced significant decline in the titer of antibodies against ND vaccine, total immunoglobulins and circulating immune complexes in imidacloprid treated group on day 45 as compared to control group. There were no significant changes in the skin thickness between treated chickens and chickens of control group. Histopathology of the bursa of Fabricius revealed edema, lymphocytic depletion in the medulla and cortex and mild interfollicular fibrosis in imidacloprid treated group. The spleen showed mild haemorrhages and lymphocytic depletion.

The research, published in the Journal of Applied Ecology, found that 3/4 of the beetle species examined had declined in number over the last 15 years. The abundance of half of these species had fallen at a rate equivalent to 30% per decade. Scientists warn that these declines, comparable to those seen in butterflies and moths over the same period, are of serious conservation concern. The study focused on ground beetles or 'carabids'. Many of these species perform valuable tasks in their ecosystems that we'd miss if they disappeared.

Earlier this year, two studies published in Science showed that colonies are severely affected when bees are exposed to neonicotinoid pesticides of the kind commonly sprayed on crops. In one study, exposure led to a significant loss of queens in colonies of bumblebees (Bombus terrestris). In the other, on honeybees (Apis mellifera), the insecticide interfered with the foragers’ ability to navigate back to the hive. Now, in a study published in Nature, researchers at Royal Holloway, University of London, in Egham, UK, show that low-level exposure to a combination of two pesticides is more harmful to bumblebee colonies than either pesticide on its own. The results suggest that current methods for regulating pesticides are inadequate because they consider only lethal doses of single pesticides. Low doses of pesticides have subtle effects on individual bees and can seriously harm colonies.

For bees on Chatham Island distance has been, in one respect, an advantage (Tyranny of Distance, October 27). It has kept at bay the Varroa mite which is their greatest threat on the mainland. But until the efforts four years ago of two energetic and devoted beekeepers, bees were a neglected and insignificant part of the island’s ecosystem. Michele Andersen and Mana Cracknell have established an apiary of about 100 hives at Kaingaroa, a tiny settlement in the island’s northern corner. Honey is a side production, their main objectives being pasture improvement from increased nitrogen as the bees pollinate clover, and the raising of queens. Improved pasture will make beef production viable. At the moment cattle roam over unfenced peat land in search of grass and are often shot by hunters for sport. Michele and Mana see the raising of queens as providing a Noah’s ark for the future.

SCOTLAND’S multi-million pound fruit growing industry is at risk unless ministers ban key pesticides that are threatening to wipe out bees, wildlife experts warned yesterday. The Scottish Wildlife Trust is urging the Scottish Government to prevent the use of neonicotinoids after research suggested that the widely-used pesticides might have a catastrophic effect on the insects, which play a vital role in pollinating crops. Feeding on contaminated pollen and nectar affects bees’ navigational abilities, which jeopardises their chances of making it back to their colonies, it is claimed.

There is a growing body of evidence that shows that neonicotinoids have a detrimental effect at sub-lethal doses on insect pollinators. For this reason, The Wildlife Trusts believe that until it can be categorically proven that neonicotinoids are not adversely impacting pollinator populations, and by extension ecosystem health, Government should adopt the precautionary principle and place a moratorium on their use on all outdoor crops.