Performance of selected Orius laevigatus (Fieber) strains fed with mixtures of astigmatid mites species

Abstract: The effective integration of predatory insects into agricultural systems is highly
dependent on the nutritional quality of available food during the initial colonization phase. This study investigates the population dynamics and field establishment of two Orius laevigatus strains: a standard commercial population (Agrobio) and a specialized line selected for its affinity for astigmatid mites (MITE2). Experiments were conducted in cage trials comparing various supplemental feeding strategies, including individual prey species, a complex blend of three astigmatid mites (Acarus siro, Tyrophagus entomophagus, and Carpoglyphus lactis), and a control diet of Ephestia kuehniella eggs. Our results indicate that the composition of the supplemental diet significantly dictates predator population growth over time. A key finding is that multi-species mite mixtures significantly outperform single-species diets in promoting the establishment of O. laevigatus. Notably, the MITE2 strain exhibited a superior synergistic response to these mixtures, achieving population densities that not only exceeded the commercial strain but also surpassed those supported by the high-cost E. kuehniella diet. These results suggest that combining the MITE2 lineage with diverse mite releases offers a strategic breakthrough for biological control. This approach enables the predator to establish robust populations within the crop independently of the target pest or expensive supplements. Consequently, high densities of natural enemies are maintained preventively, ensuring a rapid response to pest outbreaks and advancing sustainable management practices.