Thermal stress responses on developmental time, survival, and wing morphometrics in desert and coastal strains of Aedes aegypti (Diptera: Culicidae) from India.

BACKGROUND Aedes aegypti is a primary vector of dengue, chikungunya, Zika, and yellow fever diseases. 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. To address this gap, we assessed ecological adaptations in terms of development, survival, and wing length, along with molecular variations, in the Thar Desert (Jodhpur) and the east coastal (Kolkata) strains of Ae. aegypti.

METHODS Mosquito eggs (3rd generation) of the coastal and desert Ae. aegypti strains were subjected to 20, 26, 30, and 35 °C to assess the impact on developmental time, survival rate, and wing length. The mitochondrial COI gene was analysed to examine nucleotide sequence variation and protein physicochemical properties.

RESULTS The desert strain developed faster, but showed inferior survival compared to the coastal strain at all temperatures tested. Temperature also affected wing length in both strains, showing significant differences between strains at 35°C for males and at 30 °C for females. Wing length of the desert strain was less impacted by temperature increase (30 to 35°C) compared to the coastal strain for both males (1.01 vs. 1.10 mm) and females (1.04 vs. 1.07 mm), respectively. The COI gene formed two distinct clades. Three transition nucleotide mutations (Adenosine with Guanosine) altered physicochemical and structural properties of the COI protein (i.e., molecular weight, theoretical isoelectric point, total number of positively charged residues, and the number of atoms). Additionally, the bad angles, instability index, and GRAVY affected the protein.

CONCLUSION This study provides a comparative analysis linking life-history traits with genetic variation in Aedes aegypti mosquitoes from climatically distinct regions of India. Temperature affects the survival, developmental rates, and wing length of genetically varied Ae. aegypti from different ecological areas. This may refine the understanding of population dynamics and management.