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 culÂprit in sharp worldÂwide deÂclines in honÂeyÂbee colÂoÂnies since 2006 is ImÂiÂdaÂcloÂprid, one of the most widely used pesÂtiÂcides, a study from the HarÂvard School of PubÂlic Health inÂdiÂcates.
It”™s the secÂond reÂport to link that pesÂtiÂcide or closely reÂlatÂed ones to the mysÂterÂious bee die-offs, though the preÂviÂous one foÂcused on die-offs in EuÂrope priÂmarily and used a difÂferÂent methÂodÂolÂoÂgy.
MemÂbers of the HarÂvard group, led by biÂolÂoÂgist AlÂex Lu, a speÂcialÂist in enÂviÂronÂmenÂtal exÂpoÂsure, said they found “conÂvincÂing evÂiÂdence” of the link beÂtween imÂiÂdaÂcloÂprid and a pheÂnomÂeÂnon called ColÂoÂny ColÂlapse DisÂorÂder, in which adult bees abanÂdon their hives in droves.
The study is to apÂpear in the June isÂsue of the BulÂleÂtin of InÂsecÂtolÂoÂgy.
“The sigÂnifÂiÂcance of bees to agÂriÂculÂture canÂnot be unÂderÂesÂtiÂmatÂed,” said Lu. “And it apÂparÂently doesÂn”™t take much of the pesÂtiÂcide to afÂfect the bees. Our exÂpeÂriÂment inÂcludÂed pesÂtiÂcide amounts beÂlow what is norÂmally preÂsÂent in the enÂviÂronment.”
Bees, beÂyond proÂducÂing honÂey, are prime polÂliÂnaÂtors of roughly one-third of the crop speÂcies in the U.S., inÂcludÂing fruits, vegÂetaÂbles, nuts, and liveÂstock feed such as alÂfalÂfa and cloÂver. MasÂsive loss of honÂeyÂbees could reÂsult in bilÂlions of dolÂlars in agÂriÂculÂturÂal losses, exÂperts esÂtiÂmate.
Lu and his co-authors hyÂpothÂeÂsized that the uptick in colÂoÂny colÂlapse disÂorÂder reÂsulted from imÂiÂdaÂcloÂprid, a memÂber of a family of pesÂtiÂcides known as neonÂiÂcotiÂnoids inÂtroÂduced in the early 1990s. Bees can be exÂposed in two ways: through necÂtar from plants or through high-fructose corn syrÂup beeÂkeepÂers use to feed their bees. (Since most U.S.-grown corn has been treated with imÂiÂdaÂcloÂprid, it”™s alÂso found in corn syrÂup.)
In the sumÂmer of 2010, the reÂsearchÂers conÂducted a field study in WorcesÂter CounÂty, Mass. Over a 23-week peÂriÂod, they monÂiÂtored bees in four difÂferÂent bee yards; each yard had four hives treated with difÂferÂent levÂels of imÂiÂdaÂcloÂprid and one non-treated hive. AfÂter 12 weeks, all the bees were alive. But afÂter 23 weeks, 15 out of 16 of the treated hives had died. Those exÂposed to the highÂest levÂels of the pesÂtiÂcide died first.
The preÂviÂous, EuÂropean study foÂcused on neonÂiÂcotiÂnoids more genÂerÂalÂly, and emÂployed a difÂferÂent methÂodÂolÂoÂgy.
Lu said the charÂacÂterÂisÂtics of the dead hives in his study were conÂsistÂent with colÂoÂny colÂlapse disÂorÂder; the hives were empÂty exÂcept for food stores, some polÂlen, and young bees, with few dead bees nearÂby. When othÂer conÂdiÂtions cause hive colÂlapse””such as disÂease or pestÂs””many dead bees are typÂicÂally found inÂside and outÂside the afÂfected hives.
SciÂenÂtists, polÂiÂcyÂmakers, farmÂers, and beeÂkeepÂers, alarmed at the sudÂden losses of beÂtween 30 perÂcent and 90 perÂcent of honÂeyÂbee colÂoÂnies since 2006, have posed many theÂoÂries as to the cause of the colÂlapse, such as pests, disÂease, pesÂtiÂcides, miÂgraÂtoÂry beeÂkeepÂing, or some comÂbinaÂtÂion of these facÂtors.Leave a reply →