Resilient Aedes mosquito eggs withstand dry conditions by surviving in a dormant state for months. Credit: James Gathany/ CDC
Eggs of Aedes aegypti mosquitoes, which carry zika and dengue viruses, can tolerate dry periods by altering their metabolism1.
Increase in specific enzymes that counter oxidative stress and break down fat allows the eggs to survive desiccation. This finding potentially offers new ways to control the spread of the mosquito, says a team of researchers at the Indian Institute of Technology in Mandi.
Field studies have shown that Aedes eggs resist desiccation, survive for months in a dormant state, and hatch into larvae when submerged in water. How the eggs resume hatching after a long exposure to a dry environment was not well understood.
The scientists dried out Aedes aegypti eggs for three weeks and rehydrated them. They compared these eggs with those of Anopheles stephensi, a species whose eggs wither away when desiccated. After rehydration, nearly 85% of the Aedes eggs rapidly hatched into larvae, whereas none of the An. Stephensi eggs hatched after three days of desiccation.
The researchers found that the protein levels of Aedes eggs in the desiccated, stress-resistant state differed strikingly from fresh eggs – 45 proteins increased and 125 proteins decreased, while 30 did not alter during desiccation.
The desiccated Aedes eggs also showed increased levels of amino acids such as arginine and glutamine. Arginine molecules form polyamines whose synthesis, when inhibited, reduced the eggs’ ability to survive desiccation.
The researchers say molecules that inhibit the activity of polyamines could potentially be used to control populations of disease-carrying mosquitoes.
