The eggs of dengue and zika-carrying Aedes mosquitoes can endure extended periods without water, akin to plant seeds patiently waiting for germination in the absence of moisture.
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Researchers from the Indian Institute of Technology (IIT) Mandi and the Institute for Stem Cell Science and Regenerative Medicine (inStem) in Bengaluru have discovered the biochemical processes that enable the eggs of the dengue causing mosquito to survive harsh conditions and rejuvenate when favourable conditions return.

The research could potentially aid the battle against mosquito-borne diseases by enabling more effective vector-control measures. 

The details of the research have been published in the journal PLOS Biology. The paper was co-authored by Baskar Bakthavachalu, assistant professor, School of Biosciences and Bioengineering, IIT Mandi, along with Anjana Prasad, Sreesa Sreedharan, and Sunil Laxman from DBT-inStem.

Karnataka has been facing a dengue outbreak, with 11,576 cases this year as of October. Bengaluru recorded the highest number of cases in the State, with 6,093 cases over the same period.

Mosquitoes, viral vectors for various diseases, deposit their eggs in water, where they hatch. The eggs of dengue and zika-carrying Aedes mosquitoes can endure extended periods without water, akin to plant seeds patiently waiting for germination in the absence of moisture.

Despite the knowledge of this phenomenon, the molecular reasons behind the desiccation tolerance and post-rehydration survival remained a mystery until now.

The collaborative team reared Aedes aegypti mosquitoes, studying their eggs through a series of innovative experiments. By subjecting the eggs to dehydration and subsequent rehydration, they discovered that the developing larvae undergo specific metabolic changes required for survival.

“Mosquito eggs, facing drying conditions, enter an altered metabolic state to significantly increase the production of polyamines, which play a crucial role in enabling the embryos to withstand the damage caused by water loss. Furthermore, they utilise high-calorie lipids as an energy source to complete their development once they are rehydrated,” said Dr. Bakthavachalu, the lead researcher.

The implications of the research could be far-reaching as understanding these survival mechanisms provides a foundation for innovative mosquito control strategies.

By disrupting the desiccation tolerance of mosquito eggs, researchers anticipate a significant reduction in mosquito populations and disease transmission. The understanding gained from this work could potentially prevent the resurgence of mosquitoes following monsoon rains, a period traditionally associated with increased disease transmission risks.

The knowledge gained has applications beyond disease control. Similar pathways exist in agricultural insect pests, suggesting potential solutions for agricultural challenges. By deciphering these biochemical processes, scientists may pave the way for eco-friendly, targeted pest control measures, ensuring sustainable agricultural practices.