It’s July in Minnesota, and you know what that means: bugs. Clouds of bugs. Some people complain, but I generally rationalize a large population of fecund invertebrates as simply a sign of a healthy ecosystem, so yeah, we’ve got bugs, but it’s good for us.
Except for those mosquitoes. It’s hard to think charitably of some invertebrates when you’re lying in bed at night and you hear…that…high-pitched whine rising as the nearly invisible little blood-sucker buzzes by your exposed flesh. Now, in a discovery calculated to increase my irritation, I learn that the little bastards are singing a love song as they hover about, looking for an opportunity to stab me and suck my blood. “Come to me, come to me, mon chéri,” they sing, “after I gorge myself on ze fat, torpid hu-man (and daintily spit up a little backwash into his capillaries), we shall make sweet, sweet love in the moonlight and zen I shall lay a thousand eggs, and our progeny shall feast on his children!” (Sorry, but now whenever I hear them they’ve also got a silly Pepe LePew French accent.)
Here’s how you figure this out. With a tiny drop of sticky beeswax, tether a mosquito to a thin steel wire, and lift it into the air. When its feet have left the ground, it will spontaneously start flapping its wings, making its usual whine (you can stop them just by bringing a piece of paper into contact with the legs, so that it is fooled into thinking it has landed.) In the photo to the right, you’ll see a small, blocky microphone mounted within a few centimeters of the beast. Easy—now you can make a mosquito buzz at will, and get high quality recordings.
Now the interesting part: the mosquito whine is variable, and they can change the pitch by modulating the wingbeat frequency. How do you get them to change the pitch? By playing musical tones at them. It’s true: in a perverse variant of the closing scene of Close Encounters of the Third Kind, scientists are talking with mosquitos by playing tones at them, and the mosquitos are talking back by changing the tone of their whine. No word is yet available on any translations, but I suspect it will be some variations on “blood” and “sex,” emphasis on the sex.
Another thing they can do with this rig is record the conversations between mosquitoes. In the recording below (tres creepy if mosquito whines make your skin crawl), a tethered female is singing along at about 370Hz, and after about 5 seconds, a tethered male is launched nearby. His “voice” is higher pitched than hers at 595Hz, but almost immediately you’ll hear him try to sound huskier, while she raises her pitch a little bit, so that soon enough they’re singing at almost the same frequency (not quite, though—you can also hear the beating as they aren’t quite in perfect tune.)
This only works well if the two mosquitos are of different sexes. Put two males in the air at the same time, for instance, and you get a recording like the one below.
The two males first converge on the same frequency, but then after a period of anarchic oscillations, they diverge. I found the sound files difficult to pick up on that behavior, so I think us visual animals can see it better in the graphs of frequency below (D is the spectrogram of this recording).
Frequency Convergence and Divergence of Flight Tones by Pairs of Tethered Tx brevipalpis. Spectrograms of the fundamental components of flight tones of opposite (A-C) and same (D-G) sex pairs of mosquitoes (male [♂], blue; female
[♀], red). Numbers alongside each spectrogram refer to the flight-tone frequency of flying mosquito at onset of record, peak frequency of second
mosquito at take off, and frequency of both mosquitoes at end of record.
Different sex pairs sing in harmony together, but same sex pairs don’t; something clues them in about the gender of their partner from their song, which is curious, since both sexes can converge to the same frequency. The authors speculate that the key difference is responsiveness. Males respond much more quickly, but not instantaneously, to the pitch of their partner; females are slower and are in no hurry to respond.
What this means is that when two males meet, they try to synchronize, but they react to what their partner was doing just a moment before. Their “voices” dart up and down, each trying to meet the other, but never quite doing it. Two females, on the other hand, will slowly harmonize, but when one drifts away from the common frequency, the other may take a few seconds to try and match up. Their “voices” wander away from other other in slow rhythms. The only stable convergence is to match up a fast male and a slow female, where the male can rapidly lock in to her frequency, and she isn’t reacting quickly to his frequency shifts.
Two mosquitoes don’t have to actually see each other, they just sing at each other…and if they find they can make beautiful music together, they know they’re sexually compatible and should hook up. I think that’s beautiful, but I’m still going to crush their blood-sucking insectile bodies between my hands if I can catch them.
Gibson G, Russell I (2006) Flying in Tune: Sexual Recognition in Mosquitoes. Curr Biol 16:1311-1316.
there you go again with the french bashing. i amused myself by imaging that the various combinations of singing entities were human.
Not surprising, really, but still mucho interesting.
This is the coolest post ever.
PZ, I got the story from the pathetically brief LiveScience article which contained this tidbit:
Does that refer only to intraspecific interactons? Or interspecific as well? It would be pretty cool if differing species of mosquito could avoid each other as they approached on the buzz of their wings. Kind of like the courtship dance of Hawaiian Drosophila.
This paper didn’t test species-specific recognition. In the tests with artificial tones, though, they only respond to a roughly 60Hz band — anything outside that, they don’t make a strong effort to match it.
They also have an organ called the Johnston’s organ, associated with their antennae, that responds to vibrations in the air. That organ is tuned to respond most strongly to particular frequencies.
How close to the mosquitoes have to be for synchronicity to occur? I’m thinking of trips I’ve had out in the woods when they seem to be effin’ everywhere – it seems they could end up in some kind of insectian equivalent of bad vaudeville, cutting each other off, accidentally matching the wrong one…”Oh, I’m sorry sir, I was speaking to her…”
So, how long before someone figures out a way to artificially broadcast the sort of tones required to attract mosquitos? I want one to lure them away from me and, if I’m in that sort of a mood, towards others.
I’ve sometime thought that the blood-sucking mosquitos are some of the few species I wish biologists would figure out a way to eliminate. Completely, as in extinction. No-see-ums, too.
Russell, they’re on the case.
That was pop-sci, but there’s a pdf of the Proc. Roy. Soc. paper here:
http://plantbio.berkeley.edu/~bruns/pmb220/pdfs/Burt.PRS.2002.pdf
Anyway, eliminating insects is next to impossible. They’ve been around since the Devonian (the first fossil is a Collembola, and they aren’t technically insects anymore…but still) and they’re so successful that they account for about 40% of all described life.
Along the same lines as Jay, aren’t Mosquito genetics to the point where we can map genes (or QTLs) responsible for intra- and interspecific variation? I’d lay down money that the QTLs that differentiate the songs between sympatric/parapatric species pairs will be found within inversions.
Fun stuff! I haven’t seen the Finnish National Airforce in Helsinki yet, but they’ll come…
If you have a mathematician or a physicist annoying you, then get rid of them by showing them the article, especially this:
and ask them to work out the dynamics. It’ll keep them occupied for hours!
Bob
I’m just drooling right now, nothing smart to say. This study is just megacool
Amusingly, as I read this, some cicadias started their hum.
I like Dr Pretorius’ suggestion, but could it be modified slightly? Could we find a frequency they don’t like and play it to use as a repellant? Without, of course, being a human repellant?
Larry Gonick tells of an old Hindu legend about a time when humanity had just come into existence, and all the other animals got together to decide what to do about them. Almost every species voted to exterminate humankind with extreme prejudice — except the mosquito, who just said, “Mmmm, they’re so delicious.”
And thus our kind was spared.
So, could this information be used to make an artificial (preferably ultrasonic) mosquito call that would keep the real mosquitos in the “looking for love” phase and keep them out of the “sucking blood and leaving spit behind” phase of their courtship?
Well, now I know where Meredith Monk got her inspiration.
So, I want to know what happens when you get a mosquito love triangle going. Is it true for mosquitos too? The triangle never works?
Swatting mosquitoes should work – we are killing off the annoying ones. Swatting flies seems like a loosing position since they rely on speed to get away – we are killing off the slow ones. (Which bugs me no end, since mosquitoes doesn’t find me particularly attractive and tics never crawl onto me, but flies loves me. I’m usually the first to be bitten by a horsefly at the beach.)
Bacillus thuringiensis israelensis is effective in making mosquitoes go from pest to bother. It is used here around large flood delta marches near population centers with success.
I could bathe in DEET and drink half a gallon of it and I think mosquitoes would still bite me. I’ve only found one sure thing that works to keep skeeters away from me here in Houston… one ounce of essential oil of catnip in a quart of fractionated coconut oil, sprayed on every six hours or so. Active ingredient in the catnip is something called “nepetalactone,” and it’s been proven effective in some scientific study somewhere… I could Google, but will leave as an exercise for the reader so I can get back to work. :)
So, how long before someone figures out a way to artificially broadcast the sort of tones required to attract mosquitos? I want one to lure them away from me and, if I’m in that sort of a mood, towards others. Dr. Pretorius
It’d be cool if the “Mosquito” Ring Tone would draw the little buggers towards teens with cell phones that we “mature adults” can’t hear, no?
I’ve only found one sure thing that works to keep skeeters away from me here in Houston… one ounce of essential oil of catnip in a quart of fractionated coconut oil, sprayed on every six hours or so. … speedwell
And what do you do about the neighborhood felines once you smell like a catnip patch? :-)
I’ll read almost any article or journal entry that has spectrograms in it.
Don’t knock mosquitoes – they are nature’s last rearguard trying to stop human expansion into dense rain forests. We need them.
that is indeed fascinating, but it makes me glad to be very far away from Minnesota. The mosquitoes here in my part of NC are tiny and not very well organized. They’re sort of annoying, but all I have to do is think about those godawful hordes of them and that hideous whine and it makes me even happier to be where I am.
Then again there was a brown recluse on my porch last night.
Well, you know that the meek really will inherit the Earth – bacteria, viruses and insects. They are the true masters and they’ll certainly be around long after all the humans have killed each other off.
That song you here – they’re laughing at you!
And what do you do about the neighborhood felines once you smell like a catnip patch? :-)
Legitimate question. I have three kitties myself. I find that at the concentration necessary to repel mosquitoes, my cats are not particularly interested. The oil simply does not attract them in the same way the fresh or dried herb does; there must be some constituent of the whole plant that they react to that is not present in the essential oil. I’ve since found other people who report the same.
There are other essential oils that work to a greater or lesser degree; neem and lemon eucalyptus spring to mind, especially neem (in a widely reported study neem oil outperforms DEET and lasts hours longer), but they frankly stink. Catnip oil, to me, has an attractive grassy vanilla-mint sort of scent.
I’m just reporting all this since I suffer so badly myself from skeeter attacks that I am on a soapbox about this stuff, thanks for bearing with me…. LOL
Wonder if singing an artificially-generated tone-set would attract the dreaded Scottish Midge – or the equally ghastly New Zealand Sandfly?
I believe someone has worked out how to use ultrasound to stop the little buggers from flying. Not sure how practical it is for everyday use, however, and it may only work on mosquitoes whose wings are a certain length.
I am not a biologist or a scientist of any stripe; assuming that every organism has a unique place in the ecosystem that, in some way, benefits the system, can any one of you science weenies explain the place of mosquitos? Assuming that they can be eradicated without artificial harm to the system (pesticides) how would we be harmed by erasing this species?
Shyster:
“I am not a biologist or a scientist of any stripe; assuming that every organism has a unique place in the ecosystem that, in some way, benefits the system, can any one of you science weenies explain the place of mosquitos? Assuming that they can be eradicated without artificial harm to the system (pesticides) how would we be harmed by erasing this species?”
I’m not a biologist, but I’d guess they serve mainly as food. The larvae might be some kind of fish food, and the adults are bat food. Bat boxes are supposed to be a good way to keep mosquito populations down (at least that’s what they told me at the museum). Consequences might be decreases in bats and birds.
On the other hand, I’m almost willing to risk it. Worst night I’ve ever had was one night camping in the Florida Keys one summer when they didn’t spray. You could see the little bastards in the daytime hovering under bushes. Come night, they ate us alive. My friend’s back was covered in bites. Another one got off almost scot free. Bastard!
I am not a biologist either, but I dare say in many places mosquitos are so plentiful one would have to do a heck of a lot of work to exterminate them. And just because they play a role in some ecosystem or other, doesn’t entail we have to like them!
I always thought that mosquitoes were the ultimate argument against God, it is so hard to argue that they have a divine purpose rather than just existing because they can. Bloody evolution!
Rationalist to IDer
“If life is designed, then why are there mosquitoes?”
IDer
“Um ar…”
Rationalist
“If your designer is designer is responsible for those bloodsuckers, tell him he’s a f…wit!”
Much as I hate them, destroying skeeters would also decimate the bat population. I’ve heard anecotally that a bat can eat 10,000 mosquitos an evening.
But I’m ready to check out the catnip idea.
Ok, I come to you science weenies for genuine help and what do I get? Opinions that mosquitos are a pest and an irritant — I think I know that. I want to know how they fit in the scheme of things and I can’t believe that their purpose in the evolutionary scheme is that they are food for flying rats (wait, that’s pigeons). Anyway, there are other flying insects that can and would be bat food and bats would adapt. Again, what is their purpose and how would we be harmed if mosquitos disappeared?
Evolution has no purpose, so I can’t tell you what their role in any evolutionary scheme might be.
Ecologically, though, they’re important. Their larvae are converting microorganisms and decaying biomass into protein, and they and other insects are an essential food source for fish. You can get rid of them if you want fish populations to crash and to kill our lakes.
PZ,
I think I have to disagree with you there. The particular mozzies that bite and get us awake on summer nights are not the only insects with lavae that fill the ecological niche in question. We could do without them. The problem is of course to just get rid of the nasties and not all similar insects.
Thanks PZ. That is an answer I can follow. By the way, you need to be careful in your choice of words. You can probably expect to see “Evolution has no purpose” mined as a PZ Myers quote soon.
Shyster says: By the way, you need to be careful in your choice of words. You can probably expect to see “Evolution has no purpose” mined as a PZ Myers quote soon.
But that’s the point! This whole bullshit about the “purpose” of life is just the sort of confusion which leads to religion. Evolution, like life, just is.
I did my Ph. D. on mossie swarming and mating behavior. I could induce a mossie swarm over a marker on the ground and I could then manipulate the flight behavior of the mossies using a tone generator and a speaker mounted on a pole. The mossies would speed up or slow down upon the appropriate modulation of the tone etc. They were also very sensitive to the waveform of the tone. Square waves just didn’t do it for them whilst a sinusoidal shape was much more influential. I’ve changed career (I’m now a Mol. Biol. working in industry these days ) due to the concerted effort to starve all medical entomologists to death in the 1980s. Thus, I’ve not kept up with the literature since then, nor do I (nor apparently anyone else!) even remember much of the detail from my papers on the issue. None the less it was fun work to do and I got my scientist’s “union card” for it, though little else other than a post doc at Berkeley where I made my change of discipline so I could eat.
FWIW, sphinx moths also respond to sound. At the time I was doing my stuff I had a colleague, one Prof. Ikeshoji from Japan, who was able to attract these way cool huge wild sphinx moths to audio speakers set up in a similar manner in the field to mine with mosquitoes. The moths would zoom in and hover in front of speakers that were producing the correct sounds. You could almost imagine these spectacular moths thinking “Hey! Where the party at?” while hovering in front of the noisy speaker.
I came accross this line of discussions hoping to find a way to protect my children from insect bites. As I write this comment, my son is in the hospital trying to recouperate from Dengue fever. Weighing all the valid information, is it possible then to harness the tone of the female to attract the male mosquitos to somekind of ecologically, safe trap, like say a bird or bat cage or a mat of beeswax? Let’s use the sexual activeness of male insects to destroy themselves just like what we are unoticeably doing to the human species. I have read all the comments highlighting the possibilities and problems. Can we now use our intelligence for the solution? What commercially available CD or music popchart hit song replicate the female frequency? Please name it and I will buy it and set up trap using the best surround sound system available laced with beeswax. Or come to think of it, I think I will go into recording myself under the artist name “Insect buster”, and make millions in sales of insect drawing CDs and beeswax adhesive paper.
I came accross this line of discussions hoping to find a way to protect my children from insect bites. As I write this comment, my son is in the hospital trying to recouperate from Dengue fever. Weighing all the valid information, is it possible then to harness the tone of the female to attract the male mosquitos to somekind of ecologically, safe trap, like say a bird or bat cage or a mat of beeswax? Let’s use the sexual activeness of male insects to destroy themselves just like what we are unoticeably doing to the human species. I have read all the comments highlighting the possibilities and problems. Can we now use our intelligence for the solution? What commercially available CD or music popchart hit song replicate the female frequency? Please name it and I will buy it and set up trap using the best surround sound system available laced with beeswax. Or come to think of it, I think I will go into recording myself under the artist name “Insect buster”, and make millions in sales of insect drawing CDs and beeswax adhesive paper.
The noise in the ‘converging’ signals appears much smaller. Assuming this represents a compression of the Y axis in the data, the apparent divergence in the same-sex pair recordings could be misrepresentative. So based on the data shown, I am not convinced. The frequency difference should be quantified and statistically compared.
When you read this post, picture the little French skunk as the male mosquito, and the little French cat as, well, the victim. Of course, mosquitos still suck. Literally. But isn’t it more amusing doing it my way?
On the question of what roles do skeeters play in the ecosystem, they are also pollinators of wildflowers, especially in forests. From Wikipedia: http://en.wikipedia.org/wiki/Mosquito
“Males live for about a week, feeding on nectar and other sources of sugar. Females will also feed on sugar sources for energy but usually require a blood meal for the development of eggs. After obtaining a full blood meal, the female will rest for a few days while the blood is digested and eggs are developed. This process depends on the temperature but usually takes 2–3 days in tropical conditions. Once the eggs are fully developed, the female lays them and resumes host seeking.”
Speaking of no-see-ums, here’s an amusing snippet (any chocolate fiends out there?) from http://pollinators.nbii.gov/portal/community/Communities/Ecological_Topics/Pollinators/Pollinator_Species/Invertebrates/Flies,_Mosquitoes,_and_Midges/
“Chocolate lovers may be more impressed by another example of pollination by dipterans: biting midges (or “no-see-ums”) and gall midges in the Ceratopogonoidae and Cecidomyiidae families, respectively, are the only known pollinators of cacao trees, which produce the beans from which chocolate is made.”
Whiles I like wildflowers (and bats!), I’m still tempted to put a speaker playing female-skeeter songs in a bug zapper…except that this would only attract the males, and it’s the females that bite. Sigh. I guess I’ll have to get some catnip oil! I like that idea, btw–I HATE most repellants (I think I find them more repellant that the bugs do, sometimes)!
I guess the point I would make would be to echo some other posters: Don’t exterminate species lightly! Especially not an entire genus or family.
Although, if biologists want to exterminate disease-causing agents, I’d request that they work on the malaria parasite first. Yes, skeeters carry many other diseases, but I think that’s the worst one.