• 06 APR 12
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    2nd study links pesticide to colony collapse disorder

    From World Science:

    2nd study links pesticide to bee epidemic
    April 5, 2012

    Courtesy of the Harvard School of Public Health
    and World Science staff

    The likely cul­prit in sharp world­wide de­clines in hon­ey­bee col­o­nies since 2006 is Im­i­da­clo­prid, one of the most widely used pes­ti­cides, a study from the Har­vard School of Pub­lic Health in­di­cates.

    It”s the sec­ond re­port to link that pes­ti­cide or closely re­lat­ed ones to the mys­ter­ious bee die-offs, though the pre­vi­ous one fo­cused on die-offs in Eu­rope pri­marily and used a dif­fer­ent meth­od­ol­o­gy.

    Mem­bers of the Har­vard group, led by bi­ol­o­gist Al­ex Lu, a spe­cial­ist in en­vi­ron­men­tal ex­po­sure, said they found “con­vinc­ing ev­i­dence” of the link be­tween im­i­da­clo­prid and a phe­nom­e­non called Col­o­ny Col­lapse Dis­or­der, in which adult bees aban­don their hives in droves.

    The study is to ap­pear in the June is­sue of the Bul­le­tin of In­sec­tol­o­gy.

    “The sig­nif­i­cance of bees to ag­ri­cul­ture can­not be un­der­es­ti­mat­ed,” said Lu. “And it ap­par­ently does­n”t take much of the pes­ti­cide to af­fect the bees. Our ex­pe­ri­ment in­clud­ed pes­ti­cide amounts be­low what is nor­mally pre­s­ent in the en­vi­ronment.”

    Bees, be­yond pro­duc­ing hon­ey, are prime pol­li­na­tors of roughly one-third of the crop spe­cies in the U.S., in­clud­ing fruits, veg­eta­bles, nuts, and live­stock feed such as al­fal­fa and clo­ver. Mas­sive loss of hon­ey­bees could re­sult in bil­lions of dol­lars in ag­ri­cul­tur­al losses, ex­perts es­ti­mate.

    Lu and his co-authors hy­poth­e­sized that the uptick in col­o­ny col­lapse dis­or­der re­sulted from im­i­da­clo­prid, a mem­ber of a family of pes­ti­cides known as neon­i­coti­noids in­tro­duced in the early 1990s. Bees can be ex­posed in two ways: through nec­tar from plants or through high-fructose corn syr­up bee­keep­ers use to feed their bees. (Since most U.S.-grown corn has been treated with im­i­da­clo­prid, it”s al­so found in corn syr­up.)

    In the sum­mer of 2010, the re­search­ers con­ducted a field study in Worces­ter Coun­ty, Mass. Over a 23-week pe­ri­od, they mon­i­tored bees in four dif­fer­ent bee yards; each yard had four hives treated with dif­fer­ent lev­els of im­i­da­clo­prid and one non-treated hive. Af­ter 12 weeks, all the bees were alive. But af­ter 23 weeks, 15 out of 16 of the treated hives had died. Those ex­posed to the high­est lev­els of the pes­ti­cide died first.

    The pre­vi­ous, Eu­ropean study fo­cused on neon­i­coti­noids more gen­er­al­ly, and em­ployed a dif­fer­ent meth­od­ol­o­gy.

    Lu said the char­ac­ter­is­tics of the dead hives in his study were con­sist­ent with col­o­ny col­lapse dis­or­der; the hives were emp­ty ex­cept for food stores, some pol­len, and young bees, with few dead bees near­by. When oth­er con­di­tions cause hive col­lapse””such as dis­ease or pest­s””many dead bees are typ­ic­ally found in­side and out­side the af­fected hives.

    Sci­en­tists, pol­i­cy­makers, farm­ers, and bee­keep­ers, alarmed at the sud­den losses of be­tween 30 per­cent and 90 per­cent of hon­ey­bee col­o­nies since 2006, have posed many the­o­ries as to the cause of the col­lapse, such as pests, dis­ease, pes­ti­cides, mi­gra­to­ry bee­keep­ing, or some com­bina­t­ion of these fac­tors.

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