Biochemical response of Aedes aegypti and Aedes albopictus mosquitoes after exposure to thermal stress and toxin of Bacillus thuringiensis israelensis

Mosquito responds to various insecticides in the presence of environmental factors which is very important to consider in vector management as these factors affect both mosquito behavior and efficacy of insecticides. The current study aims to examine the impact of high temperatures and Bti insecticide on the biochemical profile of Aedes aegypti and Aedes albopictus mosquitoes. Late third instar larvae of Aedes aegypti and Aedes albopictus were exposed to varying temperatures (39 degrees C and 40 degrees C) and Bti concentrations (1 ppm and 1.5 ppm). After exposure, detoxifying enzymes such as Esterase (alpha and beta), Glutathione S-transferase (GST), Cytochrome P450 monooxygenase and total protein level were analyzed. It was observed that both temperature and Bti significantly influenced the level of protein and enzyme activities in both mosquito species. Aedes aegypti and Aedes albopictus exhibited a significant increase in total protein in response to temperature exposure at 40 degrees C and a decline of total protein in response to Bti exposure. Thermally pre-exposed (40 degrees C) larvae exhibited an increase in total protein content after Bti exposure. The activity of esterase decreased significantly in thermally exposed mosquitoes while Bti exposure increased the level of esterase significantly. The result of the current study also showed a significant increase in GSTs and monooxygenase after exposure to temperature and Bti in both mosquitoes. Thermally pre-exposed larvae of both mosquito species exhibited increased activities of GSTs and monooxygenase in response to Bti exposure. A significant interaction between temperature and Bti for activities of GSTs and monooxygenase was also observed. Current results showed most of the enzymes were highly expressed in Ae. aegypti than Ae. albopictus. Our results suggest that consideration of environmental factors like temperature is crucial while evaluating the efficacy of Bti that may help to make accurate prediction of Bti effect on Aedes mosquitoes.

Automated summary

The study examined the impact of high temperatures and Bti insecticide on the biochemical profile of Aedes aegypti and Aedes albopictus mosquitoes. Both temperature and Bti significantly influenced the level of protein and enzyme activities in both mosquito species. Enzymes were highly expressed in Ae. aegypti compared to Ae. albopictus, suggesting the importance of considering environmental factors like temperature in evaluating the efficacy of Bti on Aedes mosquitoes.