[G] Oral presentations in English

[G-11] Serious agricultural pests Tetranychus spider mites are also disliked by inferior competitors

◯Shiori Kinto¹, Shuichi Yano¹ (1. Kyoto Univ.)

Because species with overlapping niches typically cannot coexist, inferior competitors should have strategies to prevent competition. Panonychus spider mites share some food plant species with most important agricultural pests Tetranychus spider mites. Previous study revealed that Panonychus mites are hindered by three-dimensional webs constructed by Tetranychus mites, and experience competitive exclusion. We confirmed that fecundity of Panonychus citri is reduced on leaves with Tetranychus kanzawai webs. Therefore, we examined competition avoidance strategies of P. citri and found that P. citri avoided T. kanzawai traces at the bifurcation, indicating that P. citri can prevent encountering superior competitors. Moreover, P. citri also avoided settling onto leaf squares with T. kanzawai traces, suggesting that P. citri can detect the presence of superior competitors on the leaf. This is the first report of a repellent effect of spider mite traces on spider mite competitors. Because some spider mites also avoid omnipresent traces of predators (ants) and intraguild predators (caterpillars), survival of spider mites in the wild seems quite challenging.