Editorial: The side effects of insecticides on insects and the adaptation mechanisms of insects to insecticides

Traditionally, measurement of the acute toxicity of pesticides to beneficial arthropods has relied largely on the determination of an acute median lethal dose or concentration. However, the estimated lethal dose during acute toxicity tests may only be a partial measure of the deleterious effects. In addition to direct mortality induced by pesticides, their sublethal effects on arthropod physiology and behavior must be considered for a complete analysis of their impact. An increasing number of studies and methods related to the identification and characterization of these effects have been published in the past 15 years. Review of sublethal effects reported in published literature, taking into account recent data, has revealed new insights into the sublethal effects of pesticides including effects on learning performance, behavior, and neurophysiology. We characterize the different types of sublethal effects on beneficial arthropods, focusing mainly on honey bees and natural enemies, and we describe the methods used in these studies. Finally, we discuss the potential for developing experimental approaches that take into account these sublethal effects in integrated pest management and the possibility of integrating their evaluation in pesticide registration procedures.

Highlights • New resistance mutations are predicted to be costly but this is rarely shown in the field. • Fitness costs are predicted to be offset by ‘modifier’ loci but specific examples are rare. • Resistance mutations can be pre-existing polymorphisms or maintained by sexual antagonism. • Duplication of resistance loci can maintain a susceptible copy in permanent heterozygosis. • CRISPR-CAS can be used to make mutations in a defined genetic background for future fitness studies.