Effects of Frankliniella occidentalis (Pergande) density and loofah pollen on development and fecundity of Orius similis Zheng

Orius similis Zheng, a predatory bug that feeds on Frankliniella occidentalis (Pergande), a pest that damages vegetables and ornamental plants by feeding and transforming plant viruses. O. similis is an omnivorous predator on thrips, as well as pollen. Our study investigated the impact of five different amount densities of thrips and abundant loofah pollen on the survival, development, fecundity, and consumption of O. similis. The performance of O. similis nymphs and adults was significantly affected by the density of thrips and loofah pollen on which they fed. The highest survival and shortest development period of O. similis nymphs after feeding on 40 thrips/d, while the lowest survival rate and longest period were observed after feeding on only 5 thrips. Feeding on loofah pollen alone also significantly increased survival and decreased the nymph development period compared with feeding on 20 thrips/d. The highest prey consumption occurred at densities of 30 and 40 thrips/d, while the lowest prey consumption occurred at a thrips density of 5, regardless of whether the O. similis were nymphs or female adults. However, adding loofah pollen decreased prey consumption of nymphs and adult females. In addition, O. similis showed higher fecundity and longevity when feeding on 40 thrips/d compared to other thrips densities and adding loofah pollen. Adding loofah pollen also increased fecundity and longevity compared to feeding on thrips alone at the same density, regardless of the thrips' density. Therefore, a high thrips abundant density daily was beneficial for the development, fecundity, and longevity of O. similis, and adding loofah pollen can enhance their performance.