Evaluating artificial diets for cucurbit fruit fly, Zeugodacus cucurbitae (Coquilett) (Diptera: Tephritidae) maggots through age-stage, two sex life table approach

The cucurbit fruit fly or melon fly, Zeugodacus cucurbitae (Coquilett) is the most devastating pest of horticultural crops. Laboratory research with maggots and adults of fruit flies necessitates the need for mass rearing. A few artificial diets have been evaluated for mass rearing of Z. cucurbitae, but each had few challenges like handling and management of bulking agents, early instar maggots ensuring special care from drowning in liquid diet, lower pupal recovery and maximum mean generation time. With this mandate, the present study was formulated to evaluate the fitness of different artificial diets on Z. cucurbitae maggots in comparison to the natural hosts cucumber and pumpkin. Age-stage, two-sex life table approach was used to assess the efficacy of the artificial diets. Development duration (egg, maggots, pre-pupa and pupa), adult longevity, lifespan, adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), oviposition period, fecundity and sex ratio were observed. Eggs placed on the diets and natural hosts were observed to hatch but none of the maggots reached the second instar when fed with artificial diets labelled as D1 (Diet 1) to D5 (Diet 5), each of a different composition. Among the artificial diets evaluated, the only artificial diet labelled as D6 (Diet 6) supported the survival and growth of maggots. Hence, a life table study was evaluated for the fitness of the semi-artificial solid diet D6 in comparison to the natural hosts, cucumber and pumpkin. The biological and population parameters observed on the diet D6 were equivalent to the natural hosts except the development duration of maggots. Thus, the semi-artificial solid diet D6 based on pumpkin and common bean powder can be used for efficient mass rearing and laboratory research on Z. cucurbitae maggots.