Effect of supplemental food on the fitness of four omnivorous predator species

Abstract: The predators Orius laevigatus, O. majusculus, Macrolophus pygmaeus andNesidiocoris tenuis are extensively used in biological controls in vegetable crops. The fitness andlocal density of these predators, which are omnivores and feed on arthropods and plants, may beenhanced by the provision of supplemental food, especially when prey is scarce, and this mayimprove biological control results. The aim of our study was to evaluate the effect of foursupplemental foods: Ephestia kuehniella eggs, dry Artemia sp. cysts, the mite Tyrophagusputrescentiae and commercial multifloral bee pollen, on the reproduction and longevity of thesefour predators. Our results show that using dry cysts of Artemia sp. as factitious prey had positiveeffects on the reproduction of the predators O. majusculus, O. laevigatus, M. pygmaeus andN. tenuis. Furthermore, dry commercial multifloral bee pollen improved the longevity of thefemales of O. laevigatus, O. majusculus and M. pygmaeus as much as eggs of E. kuehniella. Drycysts and dry pollen need little or no handling to prepare them for use, are very easy to dispersein the crop and maintain their quality for a reasonable time. Further experiments need to beconducted under semi-field conditions to better evaluate the positive effect of these twosupplemental foods on predator establishment in the crop. It will also be important to evaluate theeffect of these foods on life parameters of pest species and on intraguild relationships amongpredators.