Continuous rearing of the predatory anthocorid Orius laevigatus without plant materials

The omnivorous anthocorid predator Orius laevigatus is an economically important biological control agent of several small arthropod pests including the western flower thrips Frankliniella occidentalis. Mass rearing systems for Orius bugs typically make use of plant materials such as bean pods as an oviposition substrate and moisture source. Omission of plant materials from the mass rearing system of these beneficial arthropods could drastically improve the cost-effectiveness of their production and thus stimulate their use in augmentative biological control. This study investigated the effect of a plantless rearing system, using wax paper as a walking substrate, water encapsulated in Parafilm domes, and an artificial oviposition substrate made of Parafilm and moist cotton wool, on the developmental and reproductive fitness of O.laevigatus. Plantless rearing during four generations resulted in females with an 11% lower body weight and a pre-oviposition period that was prolonged by 29%. However, other biological parameters were not negatively affected by the absence of plants. In addition, plantless-reared females had similar predation rates on F.occidentalis larvae as their peers maintained on plants. Our study indicates that the omission of plant material from the production cycle of O.laevigatus is possible when Ephestia kuehniella eggs are provided as a nutritionally optimal food source