The generalist herbivore Tetranychus urticae (Koch) adapts to novel plant hosts through rapid evolution of metabolic resistance

Genetic adaptation, occurring over long evolutionary time, enables host-specialized herbivores to develop novel resistance traits and to counteract the defenses of a narrow range of host plants. In contrast, physiological acclimation, leading to the suppression and/or detoxification of host defenses is hypothesized to enable generalists to shift between plant hosts. Here, we examined the long-term response of an extreme generalist, the two-spotted spider mite, Tetranychus urticae Koch (TSSM), to the shift to the non-preferred and novel host plant Arabidopsis thaliana. We identified the key requirement of two tiers of cytochrome P450 monooxygenases for TSSM adaptation to Arabidopsis: general xenobiotic-responsive P450s that have a limited contribution to mite adaptation to Arabidopsis and adaptation-associated P450s that efficiently counteract Arabidopsis defenses, illustrating that in about 25 generations of TSSM selection on Arabidopsis plants mites evolved metabolic resistances characteristic of both generalist and specialist herbivores.