Climate change effects on fruit flies infesting fruits

"The effect of relative humidity and temperature regimes on pupae survival of six Tephritid fruit flies, Bactrocera cucurbitae (later named as Zeugodacus cucurbitae), Bactrocera invadens (later named as B. dorsalis), Ceratitis capitata, Ceratitis cosyra, Dacus ciliatus and Dacus vertebratus was investigated. Four relative humidities namely 32,5%; 55%; 85% and 96% were tested on pupae at three constant temperatures 20°C; 25°C and 30°C on the one hand and the three constant temperatures 20°C; 25°C and 30°C with four relative humidities were tested on pupae at the respective relative humidity of 32,5%; 55%; 85% and 96% on the other hand. The results showed on one hand that for most of species, high percentages of adult emergence were obtained when the pupae were incubated at the high relative humidity of 85% and 96% at 20°C; 25°C and 30°C, except C. cosyra which gave the opposite trends at 25°C. On the other hand the pupae incubated at 20°C, 25°C and 30°C and 32,5%; 85% and 96% relative humidities gave higher percentage of emergence at 20°C and 25°C higher than that of pupae incubated at 30°C for all species. The temperature 25°C is the most favourable for the pupae emergence of B. cucurbitae, B. invadens, C. cosyra, D. ciliatus and D. vertebratus, and 20°C for C. capitata with 55% relative humidity. These results not only help to determine the ideal conditions for rearing different fruit fly species in the laboratory but also predict their abundance and geographical distribution in various agro-ecologies. The results will also contribute to the successful management of these insect pests in Africa and in the world.