While a delicious repast might serve as a prelude to romance for humans, for female mosquitoes, a blood meal is an absolute necessity for reproduction. They must get their fill before they can lay eggs.
A female Aedes aegypti mosquito consumes twice its body weight, Tulane University researcher Patricia Scaraffia said. "Can you imagine taking a meal twice your weight?" she said, calling them "amazing creatures."
But mosquitoes can transmit diseases through their saliva when they bite someone, and what happens after the insect ingests its hearty meal opens interesting possibilities for bringing about its demise.
Scaraffia, an assistant professor in the Department of Tropical Medicine and a member of the Vector-Borne Infectious Diseases Research Center at Tulane's School of Public Health and Tropical Medicine, led a team that looked at disrupting how mosquitoes metabolize blood.
Eventually, their findings might lead to more targeted ways of controlling mosquitoes.
The results of their study, published in the prestigious journal of the Federation of American Societies for Experimental Biology, were promising.
The mosquitoes whose ability to excrete waste was suppressed died sooner and produced far fewer eggs. Normally, a single Aedes aegypti female can lay up to 100 eggs, Scaraffia said.
Female mosquitoes take in more protein than they need to produce their eggs, and after they absorb the nutrients from their blood meal, they must excrete the excess nitrogen as uric acid, Scaraffia said. The researchers silenced a gene that allows the insects to use a protein called xathine dehydrogenase 1, or XDH1, to produce uric acid.
The affected mosquitoes had delayed digestion, delayed and less abundant egg laying and couldn't properly excrete waste. They died within a few days of feeding on blood.
Aedes aegypti mosquitoes, which are found throughout the southern United States, carry a number of diseases, including dengue fever, yellow fever and chikungunya. They also carry the Zika virus, which can be transmitted through sexual contact between people.
Scaraffia stressed that people need to protect themselves from mosquitoes by making sure they eliminate standing water on their property and not overwatering plants because female mosquitoes also need water to produce offspring.
Other precautions, including wearing long sleeves and pants, also are important, she said.
Scaraffia said their study, which took about three years, is a basic one. But the researchers believe they have a novel finding that will help lead to metabolism-based solutions to mosquito control.
Subsequent work by researchers can aim at identifying chemical inhibitors of XDH1, she said. That could result in killing harmful mosquitoes without affecting harmless or beneficial insects.
The point is to better understand mosquito biology through continued basic research, she said.
The mosquito is tiny, she said, "but it holds a lot of secrets."