This page is a part of the corpus (Annexe 1) used to write Stéphane Foucart and neonicotinoids.
Here, I relate what the journalist said in his article “les bourdons perdent le nord, même à très faible dose”. All quotes, originally in French, were translated by me.
Researchers led by Dave Goulson (Feltham et al. 2014) studied 6 colonies of bumblebees of initially identical size. The study was in two steps:
- For 2 weeks, the “colonies were fed in the laboratory with a sugar solution and pollen”. For 3 of the 6 colonies, 7 or 6 parts per billion of imidacloprid were added to the sugar and pollen, respectively. These rates are said to be “comparable to what pollinators encounter in nature, when the seeds have been treated with the insecticide. “
- The bumblebees were then traced with a small RFID chip and placed in the wild. Bumblebees treated with imidacloprid were also successful in foraging, but returned pollen on only 40% of their trips, compared to 63% for control bumblebees. Those who succeeded had, moreover, an hourly efficiency reduced by 31% compared to the control group.
In total, the amount of pollen collected was 57% lower for the treated bumblebees. These effects were present even one month after the end of exposure to the product.
Other studies have reportedly shown negative effects of NNI on the bumblebee. For example, the study conducted by Penelope Whitehorn and published by Science in 2012 (Whitehon et al. 2012). showed that “colonies exposed to very low doses of imidacloprid produced on average 85% fewer queens than others.”