Düşük Sıcaklıkların Aedes (Stegomyia) Aegypti (LINNEUS,1762) (DIPTERA: CULICIDAE) Türü Hayat Döngüsüne Etkilerinin Belirlenmesi

Abstract

Mosquitoes are vectors of many important diseases that threaten human and animal health. Invasive mosquito Aedes aegypti is able to transmit diseases such as Dengue, Yellow Fever, Chikungunya and ZIKA. Aedes aegypti, which is widely distributed in the Tropical and Sub Tropical zones, has established populations in the Western Palearctic Region, Madera Island/Portugal, Southern Russian Federation, Georgia, and it was detected in 2015 in the Eastern Black Sea Region of Turkey. In this study, the effect of the Ae. aegypti life stages on low temperatures were investigated for five different constant temperatures (5°C, 10°C, 15°C, 20°C and 26°C) and three different constant temperatures (-5°C, 0°C and 5°C) for cold shocking. In laboratory conditions (26°C, %60 relative humidity, 12:12 Light:Dark), Ae. aegypti eggs were left to hatch at constant temperatures of 5°C, 10°C, 15°C, 20°C 26°C and their development from egg to adult were monitored. The effects of two different food source (Fish food (BY)/Nutrient Broth& Brewer's Yeast (NB)) were investigated at these low temperatures. Hatching was observed in all temperatures. Accordingly, it has been observed that there is a direct correlation between the temperatures and the egg hatching rates; the hatching rate decreases as the temperature decrease. In this study, it was seen that development was successfully completed up to the L4 larval stage at 15°C. Adult emergence was observed only at constant temperature conditions of 20°C and 26°C. Accordingly, adults survived as 26,06±13,4 days for females, 24,83±15,52 days for males at a constant temperature of 20°C, 28,83±16,36 days for females and 16,03±5,8 days for males at a constant temperature of 26°C. In order to calculate age-specific life table parameters, cohorts consisting of 30 female and 30 male (F0) individuals were placed under constant temperature conditions of 20°C and 26°C where adult emergence was observed. Adult life table was created only at 26°C. Adult life table parameters were rate of natural increase (rm)=0.24, generation time (Tc)=21.46 and net productivity (R0)= 186.50 at 26°C. Life table parameters could not be calculated at 20°C because the new generation eggs (F1) could not hatch. Also in this study, cold shock experiments were applied to all life stages of Ae. aegypti for -5°C, 0°C and 5 °C, and the effects of shocking cold temperatures on the development of the life stages were observed. None of the life stages have survived at -5°C. Eggs that were exposed to 0°C cold shock for one day survived at a rate of 79.5±8.1% (76-94.5%). Larvae, pupae, and adult stages did not survive at this condition. Eggs survived at a rate of 87.33±8.1% (76-94.5%), larvae at 93±1.24% (92-95), pupae at 70±11.7% (58-86) and adults survived at a rate of 94±0.94% (93-95) in the constant temperature of 5°C cold shock for one day. This thesis is a preliminary study to understand the effects of low temperatures for the all-developmental stages of Ae. aegypti. Our findings could help to estimate the cold tolerance ranges and adaptations for cold habitats. The data obtained from this study will contribute to creations of distribution models and to conduct a better control program for Ae. aegypti.