Comparison of diets for rearing the larvae of Mediterranean fruit fly: nutritional and economic aspects

Abstract

The Mediterranean fruit fly Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) is the main pest of fruit crops worldwide due to its broad distribution, direct damages, and adaptation to different hosts. Developing diets for the rearing fruit flies is essential for integrated management of this pest. Mass rearing of parasitoids, selection of preferred hosts, and mass rearing of genetically modified C. capitata strains subsidize methods of biological control, cultural control, and the sterile insect technique (SIT), respectively, depending directly on the mass rearing of the Mediterranean fruit fly. The aim of this study was to assess the effectiveness of artificial diets for rearing C. capitata larvae considering the cost of those most appropriate diets. Nine diets containing different combinations of protein and energy sources (brewer’s yeast, yeast extract, pollen, soybean extract, oatmeal, corn meal, and wheat germ) were formulated. The parameters immature development time (hatching), pupal viability (emerged adults), size and weight of pupae, and adult size (wing length) were assessed. The experiments were conducted in the laboratory under controlled conditions of temperature (26 ± 1 °C) and relative humidity (70% ± 10%). Statistical analysis was performed by using ANOVA with the Tukey’s test for comparison of means. Diets based on oatmeal and soybean extract, both added with brewer’s yeast, yeast extract, or pollen satisfactorily meet the nutritional requirements of C. capitata. Moreover, diets enriched with brewer’s yeast or yeast extract presented the lowest costs; therefore, they could be used in a continuous mass-scale rearing of C. capitata. Diets based on corn meal and soybean extract, both associated with brewer’s yeast, yeast extract, or pollen are more economical, but they should not be used for rearing C. capitata because they decrease the percentage of hatching and extend life cycle. Diets based on wheat germ and oatmeal, both added with brewer’s yeast, yeast extract, or pollen are not adequate for rearing C. capitata.