[thedoc (OP)]

Dear Chris,

I was at the local store the other day and I happened to see a small device being sold that claimed to emit high frequencies (that humans can't hear) that repel mosquitoes. My question is :Is there any peer-reviewed evidence to suggest that high frequency sounds can keep mosquitoes away or are people swindled into buying a useless product?

Cheers,
Nikhil Rajagopalan
India.

P.s. Your podcast rocks; would love a reply from you guys! :-D
Asked by Nikhil Rajagopalan

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[thedoc (OP)]

We answered this question on the show...


We'll have the answer on the nect Naked Scientists Show.  Until then, what do you think?

[CliffordK]

I'm curious too.

I also have some high frequency mouse repellers which seem to hit at the top of the human hearing range, ignored by some, annoying to others.

My guess is that they all are less effective than advertised, although, for mice, it may take them some time to habituate to the devices.

[RD]

...the buzzers we tried, were a shocking waste of money, didn't offer any protection at all and offer nothing but a false sense of security. They should be removed from sale.

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[Peter the painter]

Simple answer is yes. Many species hear sounds outside human range, and there are many insect repellers on the market, look in ebay.

[confusious says]

These so called mosquitoe repelers are supposed to replecate the wing movement sound and/or vibration of a certain insect which feeds on them, the insect that eats them I cannot remember at the moment. But I can tell you, I have tried these devices along with vapour killers and flourescent high tension voltage killers, and to be honest, I cannot say any have worked, even DEET soaked wrist bands did nothing. The best way to get a good nights sleep, close all windows and spray room with ordinary fly killer, leave for an hour before entering room, climb into a mosquitoe net, and now sleep. N.B. contrary to what they say about mosquitoes biting at night, I can tell you they bite any time.

[dlorde]

The Which? report, described in the BBC News link above, found all the buzzers simulating male mosquitos or dragonflies were ineffective, but all the plug-in vapour repellents were effective. Deet is known to be the most effective available repellent (although, in my experience, it's often sold too dilute to do the job).

Apparently one in 10 people are highly attractive to mosquitoes, and 85% of this has a genetic basis. Heat, movement, and exhaled C0₂ guides mozzies to their victims, particularly people with high concentrations of steroids or cholesterol on their skin, or who produce (secrete) excess uric or lactic acid.

[grizelda]

There's a mosquito repellant app for the Blackberry playbook that emits at three different frequency settings. Two of them are inaudible to me (if there is any actual signal); the third is so piercing I can't listen to it. If this was connected to an amplifier and a good set of tweeters, I'm sure it would have no trouble clearing out a crowd (of people, dunno about insects).

[Thylacine]

l live in a particularly mosquito rich Australian suburb.  Notwithstanding the inefficacy of high frequency (HF) sound transmitted by FM broadcasting and iPhone, and the scientific surveys which damned HF noise as a mosquito repellant, I was given one of those cheap small pen-like HF sound transmitters and decided to carry out my own survey a few evenings ago. 
So dressed in a shirt and shorts and nursing a cold longneck, I sat outside contemplating the day. Such behaviour at this time of year invites mosquito attack.  Within a minute of sitting, there was a cloud of the insects buzzing around. In about three to five minutes, they were gone. I spent about an hour outside in the evening's warmth and remained unbitten. Over subsequent evenings, mosquito reaction to HF sound was consistent; an appearance, then dispersal.
I suspect that there is more to the effect that HF sound has on mosquitos, than the scientific surveys refuting such a link, suggest. Cheers! 

[chris]

Interesting - what was the name of the device you were testing?

[Thylacine]

Hi Chris,
It's called Anti-Bite and claims a 6m effective deterrent radius.

[Cynthia Lane]

i feel doubt about that. it may affect the mosquito, but i cannot be sure whether to repel them