Genetic improvement of Orius laevigatus for better fitness feeding on pollen

In many protected crops, augmentative biological control heavily relies on generalist predators, which continuous presence on the crop allows an early response to pest immigration and outbreaks. Persistence is possible by their ability to feed on alternative food, such as pollen, plant-provided or artificially supplemented. However, fitness is decreased when feeding on alternative foods, hindering performance. We present a new approach to face this challenge: genetic improvement for better fitness feeding on suboptimal food. Orius laevigatus is one of the main biological control agents used in greenhouse vegetable crops. A breeding process was carried out on the basis of a broad intraspecific variability exploration for 10-day fecundity feeding on pollen (14.2–37.9 eggs/female for 30 wild and commercial populations). Life history traits were finally compared between our two selected strains and three commercial, wild and acclimated-to-pollen unselected populations, both on rich (Ephestia eggs) and suboptimal (dry honeybee pollen) diets. Selected lines showed considerably improved values for longevity (1.5-fold), early (1.3-fold) and lifetime fecundity (1.9-fold), nymphal survival (3.5-fold), intrinsic rate of natural increase (rm) (7.3-fold) and net reproductive rate (R0) (6.7-fold) as compared to reference unselected strains when they were fed on pollen, although still lower than on the optimal diet. Selection feeding on plant material resulted in no trade-offs when feeding on the factitious prey. This improvement was due to genetic gain rather than to phenotypic plasticity to tolerate nutritious restriction. Finally, some potential contributions of these improved lines not only for augmentative biocontrol but also for artificial rearing are provided.