Daily temperature fluctuations can magnify the toxicity of pesticides.

Abstract

We review the effect of daily temperature fluctuations (DTF), a key thermal factor predicted to increase under climate change, on pesticide toxicity. The effect of DTF on pesticide toxicity may be explained by: (i) a DTF-specific mechanism (caused by Jensen's inequality) and (ii) general mechanisms underlying an increased pesticide toxicity at both higher (increased energetic costs, pesticide uptake and metabolic conversion) and lower constant temperatures (lower organismal metabolic and associated elimination rates, increased sodium channel modulated nervous system vulnerability and energetic costs). Furthermore, DTF may enhance pesticide-induced reductions in heat tolerance due to stronger effects on oxygen demand (increase) and oxygen supply (decrease). Our literature review showed considerable support that DTF increase the negative impact of pesticides on insects, especially in terms of decreased survival. Therefore, we suggest that considering DTF in ecotoxicological studies may be of great importance to better protect biodiversity in our warming world.