Influence of larval density on biological fitness of Ephestia kuehniella zeller (lepidoptera: Pyralidae)

Abstract

Mediterranean flour moth, Ephestia kuehniella, is a cosmopolitan pest of stored products, and its eggs are widely used to rear parasitoids and predators for biological control programmes. This experiment investigated how larval population density affected the survival rate and reproductive output of this species under four rearing densities (1 larva per 2 g food per vial; or 100, 500 or 1000 larvae per 50 g food per jar). The survival rate and reproductive output significantly decreased (P<0.0001) with increased larval density. On average 91, 73, 50 and 10% of neonate larvae survived to adults, and each resultant adult produced an average of 339, 321, 253 and 183 viable offspring, at densities of 1, 100, 500 and 1000 larvae, respectively. When the cost of labour is taken into consideration, a rearing density of 100 neonate larvae per 50 g food per jar is recommended to produce satisfactory quantity and quality of E. kuehniella adults and eggs.