Predatory Capacity and Functional Response of Orius laevigatus (Hemiptera: Anthocoridae) on Frankliniella occidentalis Larvae

Abstract

Orius laevigatus is an effective generalist predatory insect widely used in biological control programs against soft-bodied pests in protected and open-field cropping systems. The present study was conducted to evaluate the predatory capacity and functional response of O. laevigatus on larvae of Frankliniella occidentalis under controlled laboratory conditions. Bioassays were performed to assess predation rates across different prey densities, along with estimation of functional response parameters. The predator was reared and maintained under standardized environmental conditions, and third instar larvae of F. occidentalis were used as prey. Results indicated that predation efficiency of O. laevigatus increased with increasing prey density up to a saturation point, beyond which consumption rate stabilized due to handling time constraints. The functional response was determined to be Type II, characterized by a decelerating rise in prey consumption with increasing prey availability. Key parameters such as attack rate and handling time were estimated, demonstrating high predatory efficiency and strong potential for suppressing thrips populations at low to moderate infestation levels. The predator exhibited rapid searching ability and adaptability under laboratory conditions, highlighting its suitability for augmentative biological control programs. The study also demonstrated that temperature and prey availability significantly influenced predation performance and developmental activity. These findings confirm the importance of O. laevigatus as a biological control agent in integrated pest management systems, particularly in greenhouse vegetable production. Understanding its functional response provides valuable insights into predator–prey interactions and supports the optimization of release strategies for effective suppression of F. occidentalis populations. The results contribute to the development of sustainable, pesticide-reduction-based pest management approaches in horticultural ecosystems.