Here, I relate what the journalist said in his article “Pesticides : les mathématiques au secours des abeilles”. All quotes, originally in French, were translated by me.
A study conducted by John Bryden and published in Ecology Letters (Bryden et al. 2013) observed that exposure to very low doses of NNI can “cause colony collapse without having an acute lethal effect on each of the group insects.” At the same time, the FFAP had, on November 6, drawn up “a dramatic inventory of the beekeeping sector”.
The researchers had developed a mathematical model simulating the evolution of the colony and tested it with bumblebee colonies that were fed pollen containing 10 parts per billion imidacloprid for 42 days. Their model would have been validated.
During the first 20 days, the treated colony evolves similarly to the control colony. Then, after this “tipping point”, the “treated colonies decline, while the control colonies continue to grow.” An apidologist puts into perspective:
” These works do not constitute biological proof, but are rather a tool which allows us to possibly understand how things can happen, for his part sums up a French apidologist. A dozen similar models have already been built.“
This is, however, further proof of the flawed nature of the risk assessment procedures. [Reference to the 2012 EFSA opinion]