Life-history traits of Dacus frontalis Becker (Diptera: Tephritidae) reared at four constant temperatures

Dacus frontalis (Diptera: Tephritidae) is an emerging species affecting fruit production in Africa and may pose a serious risk to the Cucurbitaceae fruit producing industry in Europe in response to climate change. To understand how temperature affects the fitness and population dynamics of this species and consequently its invasive potential, we investigated for the first time the survival and development time of immature stages, longevity and fecundity of D. frontalis adults in the laboratory at four constant temperatures of 15, 20, 25 and 30 °C. In addition, the lower developmental threshold and thermal constant were calculated using a temperature summation model. Results showed that the rearing temperature has a significant effect on the survival, development, reproduction, and longevity of the pumpkin fruit fly. The highest survival rates of eggs, larvae, pupae, adult females and males were observed at 20 °C. The development time of immature stages and from egg to adult, decreased significantly with increasing temperature from 15 to 30 °C. Females produced a significantly higher number of eggs at 20 °C, and no oviposition was observed at 15 °C. Pupae were able to survive at 15 °C with the longest development time, suggesting that this tephritid species can overwinter as pupae in the field in North Africa. The thermal constant of egg, larval, and pupal stages were 33, 95, and 210 DD, respectively. The minimum temperature threshold of egg, larval, and pupal stages were 4.6, 13.5, and 9.5 °C, respectively. These thermal requirements may explain the seasonality of D. frontalis observed in North Africa. Implications for pest management and potential geographical distribution are discussed.