The two-spotted spider mite, Tetranychus urticae, is a cell-content feeding chelicerate herbivore, feeding on over 1000 plant species, one of which is Arabidopsis thaliana. This research uses microarray data from two A. thaliana accessions that differ in susceptibility to spider mite feeding to identify how the plant defends itself against this herbivore. Mutant analysis of induced plant defense pathways and physiological assays of mite performance indicate that A. thaliana utilizes: a) damage associated molecular pattern receptors, PEPR1 and PEPR2, to aid in perception of attack; b) jasmonic acid as the key phytohormone involved in resistance signalling; and c) indole glucosinolates as effective secondary metabolites affecting mite performance and development. My findings provide insight into how A. thaliana defends itself against this class of arthropod herbivores using defences that have previously been associated with deterrence of insect herbivores, which are distantly related to chelicerates
