Kolkata: Scientists from the Estuarine Biology Regional Centre of the Zoological Survey of India (ZSI), Ganjam, Odisha, have found that desert populations of Aedes aegypti develop faster but show lower survival rates compared to coastal populations under varying temperature conditions.
The study examined ecological adaptations of Aedes aegypti strains from Jodhpur in Rajasthan’s Thar Desert and Kolkata’s east coastal environment at four temperature regimes — 20°C, 26°C, 30°C and 35°C. Researchers observed that the desert strain developed faster than the coastal strain across all temperatures. However, the desert strain recorded lower survival rates at different temperatures.
“Aedes aegypti is a primary vector of dengue, chikungunya, Zika and yellow fever. Despite its global invasion, little is known about how populations from climatically contrasting regions adapt to varied thermal environments. Understanding survival strategies is critical for predicting population dynamics and disease transmission under climate change,” said Dr D. S. Suman, Scientist E, ZSI, and corresponding author of the study.
The researchers assessed ecological adaptations in terms of developmental time, survival and wing length, along with molecular variations, in the two geographically distinct strains.
Temperature was also found to influence wing length in both strains. Significant differences were recorded at 35°C for males and at 30°C for females. The wing length of the desert strain was less affected by temperature increase from 30°C to 35°C compared to the coastal strain in both sexes.
According to the researchers, adaptation to distinct climatic conditions may influence survival strategies of the dengue vector, potentially affecting disease transmission and necessitating fine-tuning of vector control programmes.
The findings have been published in the international infectious diseases journal Acta Tropica under the title “Thermal stress responses on developmental time, survival, and wing morphometrics in desert and coastal strains of Aedes aegypti (Diptera: Culicidae) from India.”