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

<p>We studied the food quality of the aphid <em>Rhopalosiphum padi</em> to the pirate bug <em>Orius majusculus</em> using <em>Ephestia</em> 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 <em>Ephestia</em> 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 <em>Ephestia</em> eggs or a mixed diet. The results confirm that <em>R. padi</em> is low‐quality food for <em>O. majusculus</em> as it is for other generalist predators, even though <em>O. majusculus</em> may contribute significantly to population suppression of the aphid.</p>