Here, I relate what the journalist said in his article “Deux études à grande échelle confirment les dégâts des néonicotinoïdes sur les abeilles”. All quotes, originally in French, were translated by me.
Two studies published on June 30 by Science “extinguish the last doubts that could – possibly – remain” on the damage caused by the NNI.
The first (Woodstock et al. 2017) was conducted by Ben Woodcock at 11 locations across Germany, the UK and Hungary. On each site, 3 farms cultivated rapeseed, two of which were treated with an NNI. The experiment spanned several dozen hectares. According to Dave Goulson, this was “the largest field experiment conducted on the impact of neonicotinoids on bees”. Note that the study was funded by Bayer and Syngenta. On each farm, the health of one type of honey bee, bumblebee and wild bee was monitored for one to two years. The impact of NNIs observed could vary by country. For example, the number of bees exposed to clothianidin surviving the winter was lower in Hungary than in Germany. Overall, however, it was negative. This is all the more evident when one considers the health of the hives instead of the quantity of bees (difficult to establish): 100% of the unexposed colonies survive, while this is not the case for those which are. exhibited. In wildlife, “bumblebees produce fewer queens, and solitary bees produce fewer larvae when exposure to neonicotinoids is high.” In addition, the authors find “imidacloprid everywhere, even when cultures have not been treated with this molecule, confirming the recent work of the Ecobee team in France”, concluded Dave Goulson.
The second study was conducted in Canada by researchers led by Nadejda Tsvektov. (Tsvektov et al. 2017) It involved 11 train apiaries close to cornfields treated with clothianidin, others several kilometers away. Note that corn is pollinated by wind and not by insects.The authors found a cocktail of twenty-six pesticides, including four neonicotinoids, in the colonies near or far from the fields. The closest were the most affected. They attempted to isolate the effect of clothianidin by placing bees exposed to contaminated pollen in an untreated experimental hive. They observed that their life expectancy was reduced by 25% and that “their behavior differed from that of unexposed individuals, to the point of endangering the survival of the colony. “
In light of this work, Dave Goulson concludes: “It has become untenable to continue to claim that agricultural use of neonicotinoids does not harm wild and honey bees.”