Food quality of Ephestia eggs, the aphid Rhopalosiphum padi and mixed diet for Orius majusculus

We studied the food quality of the aphid Rhopalosiphum padi to the pirate
bug Orius majusculus using Ephestia eggs as high‐quality comparison prey.
Several performance parameters were tested on individuals that had been
reared and maintained on each of the two single‐prey diets or on a mixed
diet. All fitness parameters were lower in individuals fed aphids only,
indicating poor food quality of this prey. Compared with the pure Ephestia
egg diet, the mixed diet enhanced teneral mass, while adult survival and
female starvation tolerance were negatively affected and all other traits
were unaffected. Body protein proportions were constant across diets,
whereas lipid proportion was low in the aphid treatment. Preference for
aphids was lower following a monotypic aphid diet than when reared on
Ephestia eggs or a mixed diet. The results confirm that R. padi is
low‐quality food for O. majusculus as it is for other generalist
predators, even though O. majusculus may contribute significantly to
population suppression of the aphid.