Scientists try to make mosquitoes pee themselves to death

RENO, Nev. – In a combination laboratory-office lined with beakers, petri dishes and a glass case of Madagascar hissing cockroaches, a Reno biochemist is searching for a way to make mosquitoes pee themselves to death.

By finding the key that would cause mosquitoes to meet their urinary demise by dehydration, University of Nevada, Reno professor David Schooley and his fellow researchers hope to end the hundreds of thousands of deaths caused each year by mosquito-spread malaria and to halt the spread of West Nile virus.

Schooley came closer to realizing that goal five years ago when he discovered a diuretic hormone that causes a dramatic increase in how much mosquitoes urinate.

“The reason we think this has a good chance of working is because, after a blood meal, a mosquito more than doubles its weight,” Schooley said. “That means it has to get rid of an enormous amount of fluid after feeding. It’s like a 747 with 1,000 people on board. It has to lighten the load in order to take off.”

After a mosquito finishes its meal – and only the female bites to feed the eggs she carries – it begins excreting salt and water from the blood it has just ingested, Schooley said.

“What we would hope is if we treat the mosquito … before it has its blood meal, it will dehydrate and die,” he said.

In tests, the hormone – a calcitonin-like peptide – worked when it was applied directly to what is the equivalent of the mosquito’s kidney. The problem is the peptide doesn’t penetrate the mosquito’s body when sprayed on it. So the challenge Schooley and his fellow researchers face is finding something similar that can penetrate mosquitoes and reach their Malpighian tubules, their equivalent of kidneys.

“What I want to find is a simpler, smaller molecule than the C-T peptide with the same biological effect on the mosquito,” said Schooley.

William Hawley, a malaria biologist with the Centers for Disease Control and Prevention, said most malaria specialists agree it isn’t feasible to eradicate mosquitoes, but the goal is to reduce their life span so they don’t transmit the disease.