Natural tool tells mosquito moms to lay their eggs someplace else
By Ben Coxworth
July 25, 2010
Mosquitoes could be having a tough time of it before too long. First, scientists announced an experimental new technology that utilizes gene-silencing nanoparticles to keep mosquito larvae from fully developing their protective exoskeletons. This leaves them much more vulnerable to insecticides, once they become adults. Now we have word of another study, in which researchers have identified a natural, environmentally-friendly chemical compound that causes female skitters to go elsewhere to lay their eggs.
The study was conducted at Israel’s University of Haifa, led by Prof. Leon Blaustein. His lab had already determined that mosquitoes were capable of chemically sensing a compound released by one of their larvae’s predators, the backswimmer, and would avoid laying their eggs where that compound was present. What wasn’t known until now, however, was the identity of the chemicals involved.
The team screened an array of chemicals released by the backswimmer against those released by Anax imperator, another aquatic predator that does not trigger a don’t-lay-your-eggs-here response. It was concluded that the chemicals unique to the backswimmer included those that the scientists were seeking. To narrow the field further, they then experimented with these chemicals in an outdoor, mosquito-friendly setting. Through a process of elimination, they were able to determine that a combination of the chemicals n-tricosane and n-heneicosane was the compound they were looking for.
Simply getting the mosquitoes to go elsewhere sounds like it wouldn’t have much of an effect on their total population, but Blaustein says it should. He claims that mosquitoes have about a 20 percent chance of mortality every day, so the longer they have to spend looking for a breeding ground, the higher the chance they won’t live to do so. Also, the remaining “predator-free” areas will end up being more crowded with larvae. This means that there will be more competition for resources amongst those larvae, resulting in fewer and weaker adults.
“While we see this as a potentially large breakthrough in developing another weapon against mosquitoes, the work is not over” states Blaustein. “We hope this breakthrough will spur further research to chemically determine other effective predator-released chemicals, particularly ones that are long lasting and then tested for their efficacy.”
The research is about to be published in the journal Ecology Letters.