PITTSBURGH, Pa. — Male mosquitoes track down potential mates by homing in on the sound emitted by the wings of flying females. But stereo speakers that broadcast the female’s buzz can easily fool the males, a teen researcher finds. If those guys become so attracted to the fake buzzing, they might just ignore the real gals. And that could trim populations of these disease-carrying bugs by reducing their mating.
Mosquitoes carry many diseases, notes Shantanu Jahkete. This 10th grader attends South Fork High School in Stuart, Fla. In his home state, Aedes aegypti is the most common mosquito. It can transmit the viruses responsible for a number of sometimes fatal diseases. These include dengue fever, yellow fever and West Nile disease, he notes. So, Shantanu decided to look for a way to reduce the numbers of mosquitoes. Fewer of these bugs should mean fewer people will get sick.
Only the female mosquitoes bite people. So many researchers have studied how to kill them. Far fewer scientists have looked at targeting males, Shantanu says. Yet if they don’t mate with females, insects populations should shrink. So Shantanu identified the sounds that allowed the male mosquitoes to find females.
To do this, he designed a simple computer program that would make a small speaker vibrate. The rate at which it vibrated, its frequency, could be altered. Then, the teen placed the speaker near a large box containing 100 male mosquitoes. Frequencies between 350 and 500 hertz proved most effective at getting the guys’ attention. (For comparison, those are the frequencies made by keys near the center of a standard piano keyboard.)
Then, Shantanu designed a more complicated computer program. Over the course of 25 seconds, it gradually changed the sound from a low of 350 hertz to a high of 500 hertz and then back again. In tests, repeated broadcasts of this cycle attracted male mosquitoes.
When he broadcast the same frequencies to a box full of female mosquitoes, they showed no interest. But that’s not surprising, the teen notes. Those females don’t use sound to search for mates.
In his final set of tests, Shantanu broadcast the buzzing near a box that contained both males and females. In these trials, about 80 percent of the males ignored the females and instead searched for the source of the fake buzzing.
The finding suggests people could use tiny speakers to effectively interfere with mosquito mating. The broadcasts could simply lure males away from real-life partners. Or, the buzzing could be used to lure males to a bug-zapper that kills them. Shantanu provided details of his research at the 2015 Intel International Science and Engineering Fair. This event was created by the Society for Science and the Public (which also publishes Science News for Students). This annual competition brought 1702 finalists here, this year. They came from more than 70 different countries.
The device Shantanu designed can be built for less than $20. Because it’s programmable, it could be used to attract other species that home in on buzzing frequencies. (In general, the larger a mosquito’s wings are, the lower the frequencies its wings produce during flight, Shantanu notes.)
In many regions, the teen notes, mosquitoes have developed a resistance to the chemicals once used to kill them. In some places, certain bug-killing chemicals have been banned due to their toxic effects on humans and other creatures. Against this backdrop, Shantanu’s new device could prove a powerful new tool in the fight against mosquitoes and the diseases they carry.
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Aedes aegypti A species of mosquito that can carry several tropical diseases, including dengue fever, yellow fever and West Nile virus.
dengue fever A potentially lethal infectious disease transmitted by mosquitoes. No vaccine yet exists to prevent infection with the virus responsible for the disease, which causes high fevers, severe headache, joint pain, pain behind the eyes, rash, bone pain and sometimes mild bleeding. A more severe form of the disease, known as dengue hemorrhagic fever can cause uncontrolled bleeding if not treated right away.
hertz The frequency with which something (such as a wavelength) occurs, measured in the number of times the cycle repeats during each second of time.
insecticide A poison applied to kill insects.
malaria A disease caused by a parasite that invades the red blood cells. The parasite is transmitted by mosquitoes, largely in tropical and subtropical regions.
Society for Science and the Public (orSSP) A nonprofit organization created in 1921 and based in Washington, D.C. Since its founding, SSP has been not only promoting public engagement in scientific research but also the public understanding of science. It created and continues to run three renowned science competitions: The Intel Science Talent Search (begun in 1942), the Intel International Science and Engineering Fair (initially launched in 1950) and Broadcom MASTERS (created in 2010). SSP also publishes award-winning journalism: in Science News (launched in 1922) and Science News for Students (created in 2003). Those magazines also host a series of blogs (including Eureka! Lab).
West Nile disease A disease caused by a virus that is transmitted by mosquitoes. Most people develop no symptoms. But about one in five infected people will get a headache, body aches, joint pains, vomiting, diarrhea, fever or some rash. A very small share of infected people will also develop coma, seizures or paralysis.
yellow fever A disease that creates flu-like symptoms that can start with fever, chills, headache, backache and vomiting. Roughly 15 percent of patients may go on to develop more serious disease. This can lead to uncontrolled bleeding, the failure of multiple internal organs — and death.