Francisco Sánchez-Bayo
Honorary Associate Professor, School of Environmental and Life Sciences, University of Sydney, Australia
This is an impressive study because of the breadth of pesticides tested (over a thousand) and because of its experimental design that covers not only individual chemicals, but several mixtures in a gradient of realistic concentrations. In addition, it includes effects on mosquito larvae and butterfly caterpillars to compare results.
The merit of this work is in demonstrating that insect exposure to non-lethal pesticide residues is of more importance than might be thought. Of greater concern are the negative effects of a cocktail of molecules on reproduction. This confirms what we already indicated a few years ago, saying that pesticides - not only insecticides, but all other plant protection products on the market - are a major cause of insect decline, even more so than climate change. In fact, the study confirms that temperature only increases the magnitude of the effects of those chemicals, but it is clear that such effects would not occur if the pesticides were not present: the cause is the pesticides, not the temperature!