RENEE MONTAGNE, host:
We go to mosquitoes now. In an unusual experiment, scientists have discovered something romantic about the sounds of mating mosquitoes; the male and female of one species perform a duet of truly operatic skill. NPR's Christopher Joyce has this story about a flight of acoustic fancy.
CHRISTOPHER JOYCE: Sometimes scientists do strange things, like anesthetizing mosquitoes and gluing them to a tiny string or tether. When the mosquitoes wake up, well, neurobiologist Ron Hoy can explain.
Dr. RON HOY (Neurobiology and Behavior, Cornell University): We tethered a female, got her flying, and then took a tethered male and brought the male within a couple of centimeters of the flying female, and then the interaction would begin.
JOYCE: The interaction being - well, no, not what you think - not at first, anyway. The female mosquito, of the species Aedes aegypti, will not mate with just any male who flies by. First, the male must produce the right flight tone.
(Soundbite of flight tone)
JOYCE: That's the sound made by his beating wings.
Dr. HOY: When the male now is brought close to the female, what we see is an acoustic interaction. There's going to be variation of the flight tones; the male will adjust whatever he's been doing to bring about a match.
JOYCE: What they do is vary the pitch of their flight tones until they're a perfect duet. The male's pitch is at about 600 cycles per second; the female's, a little lower, at 400 cycles per second. In music, he's roughly a D, and she's about a G. And then, something very special happens...
(Soundbite of flight tones)
JOYCE: If you listen closely, you can detect a third tone - an overtone, in musical terms - fainter, more ghostly than the two main mosquito tones, up at 1200 cycles per second. OK, it's no "Madame Butterfly," but hey, these are bugs. The important thing is, once the mosquitoes detected this overtone, they mate. At his laboratory at Cornell University, Hoy tested this by creating just the 1200Hz overtone with audio equipment. When he played it for mosquitoes, they responded to it.
Dr. HOY: The interesting thing about mosquitoes is that, you know, if you're tone deaf, you're going to be squat out of luck, aren't you?
(Soundbite of laughter)
Dr. HOY: Because you're not going to catch that modulation. So, I think this is pretty amazing stuff.
JOYCE: And mysterious. Why would mosquitoes do this? Hoy says producing the perfect pitch might be some kind of proof of male mosquito macho. Certainly, singing for sex isn't that unusual in animals. Rex Cocroft, a behavioral biologist at the University of Missouri, has recorded lots of bugs doing that, but he says the mosquito duet is one of a kind.
Dr. REX COCROFT (Behavioral Sciences, University of Missouri): We think of insects as being masters of timing and rhythm and not so much masters of pitch.
JOYCE: Now, humans are also masters of pitch, and some scientists wonder whether we learn some musical rules by listening to animals, even mosquitoes.
Dr. COCROFT: So, for example, when people were writing early melodies, like Gregorian chants, well, when you have a large jump up in frequency, then you tend to drop down stepwise, and people were asking, well, do animals show similar kinds of rules?
JOYCE: If that sounds crazy, consider this: The interval between the male mosquito's tone and the female's is quite close to what musicians call a perfect fifth.
(Soundbite of perfect fifth piano notes, staccato)
JOYCE: In fact, composers for centuries considered the interval of a fifth to be the most euphonious.
(Soundbite of perfect fifth piano notes, carried out)
JOYCE: So, if mosquitoes have it right, all you need to do is find a melody with an interval of a fifth, and you're guaranteed romantic success.
(Soundbite of song "Feelings")
(Soundbite of flight tones)
Mr. ALBERT MORRIS: (Singing) Feelings, nothing more than feelings...
JOYCE: The mosquito research appears in this issue of "The Journal: Science." Christopher Joyce, NPR News.
(Soundbite of song "Feelings")
(Soundbite of flight tones)
Mr. MORRIS: (Singing) Trying to forget my feelings of love...
MONTAGNE: OK. So, you can watch a video of a mosquito in pursuit of love at npr.org. You're listening to Morning Edition from NPR News.