Function of the web box as an anti-predator barrier in the spider mite,<Emphasis Type="Italic"> Schizotetranychus recki</Emphasis>

Spider mites inhabiting Sasa bamboo show considerable variation in traits believed to be the result of coevolution between predator and prey. In Schizotetranychus recki Ehara inhabiting the hairy leaves of a dwarf bamboo, Sasa senanensis, all quiescent stages, including eggs, appear within web boxes in the leaf hairs of their host plant, and this habit is thought to be a trait involved in predator avoidance. To test this hypothesis, the survival rates of S. recki eggs inside a web box and those freed of a web box were assessed in relation to six predator species that co-occur with the spider mite in the field. The results clearly show that the webbing behavior (web box) of S. recki has a function in avoiding five predator species. However, one predator species, Agistemus summersi Ehara, preyed more on eggs protected by a web box. This suggests that this predator species has a special trait to overcome the nest barriers.