Ecotoxicological studies have shown considerable variation in species sensitivity for chemical compounds, but general patterns in sensitivity are still not known. A better understanding of this sensitivity is important in the context of environmental risk assessment but also in a more general ecological and evolutionary one. We investigated the metabolic rate or more precise the specific somatic maintenance (expressed in J cm−3 d−1, at a standardised body temperature of 20 °C) on the sensitivity of a species to chemical poisoning. The sensitivity of a species was expressed in terms of its threshold concentration for survival, the no effect concentrations (NEC, in µmol/L). Somatic maintenance data were based on the ‘add-my-pet’ database hosted by the VU University of Amsterdam. NECs were derived from the US-EPA ECOTOX database. We focussed on four pesticides; two that need a metabolic activation, Chlorpyrifos and Malathion, and two without metabolic activation, carbofuran and carbaryl. All four pesticides showed a similar response: a strong negative correlation between the specific somatic maintenance and the NEC. We discuss possible explanations, deviations and ecological implications.