Predation and oviposition by predatory Stethorus japonicus, Oligota kashmirica benefica, and Scolothrips takahashii in egg patches of various spider mite species

Predation and oviposition by three predacious insects Scolothrips takahashii Priesner (Thysanoptera: Thripidae), Stethorus japonicus H. Kamiya (Coleoptera: Coccinellidae), and Oligota kashmirica benefica Naomi (Coleoptera: Staphylinidae)] were examined using egg patches of three spider mite species Amphitetranychus viennensis (Zacher), Tetranychus urticae Koch, and Panonychus mori Yokoyama (all Acari: Tetranychidae)] that are pest species on Japanese pear Pyrus serotina Rehder (Rosaceae)]. Scolothrips takahashii females consumed more prey and laid more eggs in A. viennensis and T. urticae egg patches than in P. mori egg patches. Females also left P. mori egg patches sooner than they left other egg patches even at high prey density. Predation and oviposition of S. takahashii in a prey patch were greatly enhanced by the complicated webs produced by A. viennensis . Stethorus japonicus females consumed significantly more prey and laid more eggs in A. viennensis egg patches than in P. mori egg patches, with intermediate values in T. urticae egg patches, reflecting the quality of each spider mite species as prey. Oligota kashmirica benefica females consumed more prey and laid more eggs in A. viennensis and T. urticae egg patches than in P. mori egg patches, particularly at high prey density. However, predation and oviposition by O. kashmirica benefica increased greatly with increasing prey density, even in P. mori egg patches, indicating that prey density was the most important factor in predation and oviposition by this species. These results are discussed in relation to the potential effect of each predator on the suppression of different spider mite species on Japanese pear.