New study links com­mon pes­ti­cide to bee deaths

Kuwait Times - - HEALTH & SCIENCE -

Two of the most ex­ten­sive field stud­ies con­ducted to date in Europe and Canada have con­firmed the hy­poth­e­sis that neon­i­coti­noid in­sec­ti­cides are harm­ful to bees and other pol­li­nat­ing species. The re­sults, pub­lished Thurs­day in the US jour­nal Sci­ence, also re­veal that lo­cal en­vi­ron­ments can mit­i­gate the im­pact of the pes­ti­cide, which is widely used in farm­ing de­spite be­ing dubbed a “bee killer.” The chem­i­cal-which acts on the ner­vous sys­tem of in­sects-had a “largely neg­a­tive” ef­fect on the pol­li­nat­ing in­sects that are es­sen­tial to many crops.

It re­duced their re­pro­duc­tive suc­cess and boosted mortality rates, ac­cord­ing to the re­search that was part funded by the Ger­man chem­i­cals com­pany Bayer and Switzer­land’s Syn­genta. “In the light of this new study, con­tin­u­ing to claim that use of neon­i­coti­noids in farm­ing does not harm bees is no longer a ten­able po­si­tion,” said David Goul­son, a biology pro­fes­sor at Bri­tain’s Univer­sity of Sus­sex who did not par­tic­i­pate in the study.

The first ex­per­i­ment, con­ducted over a to­tal of 2,000 hectares (5000 acres) in Great Bri­tain, Ger­many and Hun­gary ex­posed three bee species to win­ter oilseed rape crops with seeds coatings con­tain­ing ei­ther cloth­i­an­i­din from Bayer CropS­cience or Syn­genta’s thi­amethoxam. The coatings were tem­po­rar­ily banned by the Euro­pean Union in 2013 due to con­cerns re­gard­ing their im­pact on bee health, though there are now plans to ban them com­pletely in fields but not in green­houses.

The re­searchers found ex­po­sure to the pes­ti­cide re­duced win­ter sur­vival rates in Hun­gary, where the colony pop­u­la­tion fell by 24 per­cent and in Bri­tain where sur­vival rates were “very low.” Ger­many did not see a dra­matic de­cline, which lead au­thor Ben Wood­cock put down to the avail­abil­ity of al­ter­na­tive flow­er­ing re­sources. All three coun­tries saw a de­cline in re­pro­duc­tion rates, linked to resid­ual neon­i­coti­noid in nests. The se­cond study con­ducted in Canada showed that worker bees and queens ex­posed to the in­sec­ti­cide died ear­lier, while the over­all health of colonies was also weak­ened.

Worker bees ex­posed to the treated pollen dur­ing their first nine days had their life spans cut short by 23 per­cent, were un­able to main­tain a healthy lay­ing queen and had poor hy­giene. The re­searchers were surprised to learn the contaminated pollen the hon­ey­bees col­lected did not be­long to corn or soy­bean plants orig­i­nally treated by the in­sec­ti­cides. “This in­di­cates that neon­i­coti­noids, which are wa­ter sol­u­ble, spill over from agri­cul­tural fields into the sur­round­ing en­vi­ron­ment, where they are taken up by other plants that are very at­trac­tive to bees,” said re­searcher Nadia Tsvetkov.—AFP

LILLE: A pic­ture taken in Lille, north­ern France shows a bee on a flower.—AFP

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