Behavioral response of the generalist predator Orius insidiosus to single and multiple herbivory by two cell content-feeding herbivores on rose plants

Multiple herbivory by arthropods with distinct feeding modes often reduces the attractiveness of herbivore-induced plant volatiles to the third trophic level, while herbivory by two species with the same feeding mode yields variable effects. So far, only few studies have examined multiple herbivory with two cell-content feeders. Here, we addressed the effect of multiple herbivory in rose plants by two cell-content feeders, Tetranychus urticae Koch (Acari: Tetranychidae) and Frankliniella insularis (Franklin) (Thysanoptera: Thripidae), on the olfactory preference of the minute pirate bug Orius insidiosus (Say) (Hemiptera: Anthocoridae), a generalist predator, to herbivore-induced plant volatiles (HIPVs). Additionally, we investigated whether the predator’s olfactory preference for HIPVs emitted by rose plants is associated with its feeding preference and prey quality. Y-tube olfactometer assays revealed that O. insidiosus was equally attracted to volatiles emitted by mite- or thrips-infested roses. Although HIPV blends from single-infested and multiple-infested rose plants differed in qualitative and quantitative terms, the minute pirate bug did not discriminate the odors of thrips- or mite-infested plants from multiple-infested plants. Congruent to the olfactory preference toward HIPVs, O. insidiosus did not show preference for either prey species, but consumed larger numbers of spider mites than thrips to complete its development. Therefore, our results showed that multiple herbivory by two cell-content feeders do not change the attractiveness of HIPV emissions compared to those of single-infested rose plants, and that lack of preference of the minute pirate bug to HIPV emissions induced by either spider mites or thrips favors the location of suitable prey.