show Abstracthide AbstractPhytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) is a predatory mite species of considerable commercial importance as a specialist biological control agent (BCA) of herbivorous mite pests of the genus Tetranychus (Acari: Tetranychidae).Certain plant species have proven challenging for P. persimilis predators, diminishing the efficiency of biological control. However, greenhouse and laboratory tests suggest that the fitness of P. persimilis exposed to a hostile plant environment can improve over a few generations.This study used the P. persimilis - T. urticae predator-prey system to perform an experimental evolution study of P. persimilis on different host plants. In association with phenotypic studies, we used transcriptomics to contrast the expression profiles of the mite populations on bean, tomato, and cucumber plants, assessing host plant-specific responses to gain deeper insights into adaptation mechanisms to the less suitable host plant tomato.