Astigmatid mites as supplementary food in crops for Orius laevigatus (Hemiptera: Anthocoridae) strains adapted to suboptimal feeding

Abstract: Integrated Pest Management (IPM) using biological control agents has proven highly effective in many crops, particularly those grown in greenhouses of the Mediterranean area. A key factor in this success is the use of omnivorous predators, which can feed on various prey and survive on alternative food sources when primary prey is scarce. Orius laevigatus is a prominent example of such an omnivorous predator, widely used in the Mediterranean basin and northern Europe. While it is essential for controlling different species of thrips, it can also feed on pollen, allowing for preventive releases before pest outbreaks. However, when pollen is limited, supplementary food sources are often necessary. Traditionally, Ephestia kuehniella eggs or Artemia cysts have been used, but their cost can be prohibitive. Astigmatid mites, commonly used to feed phytoseiid mites, are a more cost-effective alternative. While hemipteran predators generally don’t thrive on these mites, the Biocontrol Selection Lab in Cartagena has successfully selected O. laevigatus strains that exhibit improved survival and fecundity when fed astigmatid mites. Comparative studies between selected and commercial O. laevigatus populations revealed significant differences in performance when fed on various astigmatid mite species. The selected strains displayed greater nymphal survival and fecundity, particularly when fed on Acarus siro. Therefore, A. siro emerges as a promising, cost-effective supplementary food source to enhance the establishment of selected O. laevigatus strains within biological control strategies.