Data from: Suppression of plant resistance may be a common trait among adapted herbivores

Herbivores have evolved distinct strategies to cope with plant defences prior to becoming a pest. Some evolved resistance to toxic compounds, others suppress host toxin production. These traits seem to co-occur within herbivore species, particularly among spider mites, which are a priority pest in many crops. The intraspecific variation within the spider mites is a model for adaptive pest evolution on crops such as tomato. Empirical data collected from non-solanaceous wild host plants suggests that natural populations predominantly comprise individuals capable of inducing tomato defences, while a small proportion suppress these defences. Additionally, resistant individuals are observed only rarely within these populations. This study aims to investigate the presence of these traits within populations adapted to tomato plants. Here, Tetranychus urticae populations sampled from tomato at three field sites were compared. To discriminate between mites that induce/suppress defences and to assess their degree of resistance, the magnitude of induced defences was measured and aligned with oviposition data. The expression of effector 84 was also assessed, to determine if its magnitude of expression is a good predictor of suppression with the magnitude of suppression. Surprisingly we observed that that suppression is the dominant phenotype in mite populations collected from field-grown tomatoes. Our results suggest that suppression may be rare only at the beginning of an herbivore's adaptive trajectory after colonization of a novel host but may rapidly become common due to natural selection. This suggests the possibility that suppression potentially represent a prevalent phenotype among host-adapted herbivores and, consequently among pests.