Predator-prey interactions and life history of Orius laevigatus and O. majusculus feeding on flower and leaf-inhabiting thrips

Summary

Thrips (Thysanoptera: Thripidae) are major pests in horticulture worldwide. Longstanding biological control strategies that have been developed for flower thrips such as Frankliniella occidentalis (Pergande) are being disrupted by the recent introduction of leaf-inhabiting thrips such as Echinothrips americanus Morgan and Thrips setosus Moulton in Northern Europe. In this study, we evaluated the predator–prey interactions, predation capacity, juvenile development and adult reproduction of the two commercial anthocorid predators Orius laevigatus (Fieber) and Orius majusculus (Reuter) (Hemiptera: Anthocoridae) on these thrips. In behavioral assays, predators were more successful in subduing and consuming sedentary leaf-inhabiting thrips adults compared to the highly mobile F. occidentalis. Furthermore, O. laevigatus was more successful in subduing prey compared to the bigger predator O. majusculus. Female adults of O. laevigatus and O. majusculus killed 18 and 20 F. occidentalis adults, respectively, in 24 h, while the kill rate was around two times higher when predators were offered E. americanus or T. setosus as prey. Developmental and reproductive parameters of both Orius predators were more favorable when feeding on the leaf-inhabiting thrips compared to F. occidentalis. This was further evident in the higher intrinsic rates of increase (r_m) we recorded on a diet of E. americanus compared to F. occidentalis (0.162 and 0.148 females/female/day for O. laevigatus, respectively; 0.148 and 0.127 for O. majusculus, respectively). Our findings show that E. americanus and T. setosus constitute high quality prey for anthocorid predators, highlighting the potential of these predators for effective pest control.