Animals develop behavioral strategies to reduce predation risk, typically due to higher trophic levels. However, predation risk can arise not only from carnivores but also from large herbivores. This is because small arthropods that share food plants with large herbivores may be incidentally consumed along with the food leaves. Spider mites (Tetranychidae) and their predators (Phytoseiidae) face mortality risks when the leaves they inhabit are consumed by lepidopteran larvae (hereafter ‘caterpillars’). Despite this obvious threat, little attention has been paid to the incidental predation of mites by herbivores or to the defensive strategies mites employ against it. We hypothesized that both herbivorous and predatory mites avoid caterpillar traces to reduce the risk of incidental predation. We examined whether spider mites Tetranychus urticae and Tetranychus kanzawai, as well as predatory mites Neoseiulus womersleyi and Euseius sojaensis, avoid leaves bearing the traces of caterpillars such as the sphinx moth, swallowtail butterfly, and cutworm. We placed leaf segments that had been walked on by caterpillars alongside those that had not, and introduced one female adult spider mite or predatory mite into this apparatus. In total, 113 T. urticae, 108 T. kanzawai, 87 N. womersleyi and 94 E. sojaensis were used. And then, their settlement or oviposition sites were recorded to determine avoidance of the caterpillar traces. To verify whether chemical components contained in caterpillar traces caused avoidance, we examined the avoidance response of T. kanzawai to filter paper applied with caterpillar trail extract. Spider mites significantly avoided settling on leaves bearing caterpillar traces, and predatory mites also laid fewer eggs on such leaves, suggesting that these mites can prevent incidental predation by caterpillars to some extent. Tetranychus kanzawai also avoided extracts of caterpillar traces, indicating that chemical components of caterpillar traces are responsible for the avoidance. These findings provide the first evidence that both herbivorous and carnivorous mites avoid traces of herbivorous animals. The consumption of small animals by large herbivores has traditionally been considered incidental and ecologically negligible. However, the presence of defensive strategies can be seen as circumstantial evidence that voracious caterpillars can exert significant selective pressure on much smaller arthropods.