Effects of diet on the fecundity of continuously mated females of the Melon Fruit Fly Zeugodacus cucurbitae (Diptera: Tephritidae).

The melon fruit fly, Zeugodacus cucurbitae, is a major fruit pest in Bangladesh. The Sterile Insect Technique (SIT) has proved effective in controlling the melon fly. One of the main challenges of SIT is that it is expensive to rear a large number of flies in the laboratory. Minimizing rearing cost without compromising reproduction capabilities is important. If the fly colony is maintained with a good dietary supplement, competitive adults could bring about an effective suppression in the field population. In the present study, we tried to identify the optimal diet by altering yeast sugar ratios in an artificial diet to maximize egg production in Z cucurbitae. The melon fly stock was housed in steel-frame cages covered with a nylon net, maintained at a temperature of 25±5⁰ C, a humidity of 65-70%, and 12:12 L: D at the fruit fly laboratory of the Institute of Food and Radiation Biology (IFRB), Atomic Energy Research Establishment (AERE), Savar, Dhaka. The flies were provided with ad libitum food and water. We recorded the fecundity (no of eggs) of continuously mated females. Four feeds with varying yeast-to-sugar ratios were provided: F1 (0: 100, Y: S) (refers to sugar only), F2 (1.96: 98.04, Y: S), F3 (4.76: 95.24, Y: S), and F4 (25: 75, Y: S). The results revealed that diet significantly affected female fecundity. The mean fecundity of continuously mated females maintained on the four diet types, i.e., F1, F2, F3, and F4, was 125, 311, 380, and 492, respectively. Our study showed an increase in mean fecundity, as well as the highest fecundity, with an increase in the yeast-to-sugar ratio; fecundity was highest for the ratio of 25% and lowest for 0%. These results could be valuable for the population dynamics studies and mass rearing of Z. cucurbitae.