SPEAKER: This way, reflecting, and then going through the beam expander-- now, how big can this beam expander make the film volume?
ITAI COHEN: Yeah. It's about a centimeter. So inside there, it's about--
Our lab focuses on getting large numbers of videos of insect flight and then analyzing those with software that we've built to extract the wing and body positions and orientations.
SPEAKER: Do you think the fringe on the bottom of the wing plays a role at all in the--
ITAI COHEN: In terms of the mosquitoes, I have to say that from my point of view, there's also this very compelling story of the mating behavior. It's really fascinating what biology and evolution have come up with as ways to distinguish between appropriate mates.
Apparently, the females flap at a particular frequency. And the females will choose the male that is best able to match that frequency with the flapping or beating of his wings.
Where's the laser?
SPEAKER: So here--
ITAI COHEN: We have three Phantom high-speed video cameras that can download their images directly onto a computer. We're filming at around 8,000 frames per second. That's all we need in order to capture about 40 pictures for each wing stroke. The cameras are focused on a very, very small volume in the box that the flies or mosquitoes can roam around in.
And we trigger the cameras to record by shining two laser beams through the filming volume and having two detectors. So when the mosquito comes in and triggers both laser beams, the cameras record. They download the data onto a computer. And then they refresh and are ready to go again, and it's all automated.
RON HOY: And he is bending his abdomen a little bit. They use their afternoon for rudders.
ITAI COHEN: The high speed and high resolution really allows us to get at how these animals are controlling their flight, how they're moving their wings so precisely in order to get these different maneuvers to happen.
I have to say that all of this was really spearheaded by Leif Ristroph, who is just a phenomenal graduate student working in our lab. He's the guy who put together this apparatus and has really been one of the leaders in developing the techniques in tracking insect flight.
RON HOY: Well, its leg splayed out, just as we saw before.
ITAI COHEN: In terms of the mosquitoes and this particular phenomenon of beating the wings, I think that's Ron Hoy's expertise. And so those were the kinds of things that we get by having a campus like Cornell, where people can interact with one another. That's what's fantastic about Cornell. You really do get these groups coming together to make an impact that's larger than the sum of the parts.
I think with the mosquitoes, if we really understood the mating habits of these animals, then we could disrupt it in the wild and maybe prevent outbreaks of malaria in stricken areas. And then from an even larger perspective, again, these animals, they fly very differently from other insects.
Their wings are much smaller. They flap over a much shorter range of angles. And so the question is, how are they able to manipulate their limbs or their wing motions in order to create the maneuvers? It's another fascinating story that I can't wait to sink my teeth into.
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Cornell physicist Itai Cohen and his graduate student, Leif Ristroph, have developed a way of taking very high speed video--8000 pictures per second or about 40 frames per wing beat--of free-flying mosquitoes. In collaboration with Laura Harrington and Ronald Hoy they have analyzed how mosquitoes actually fly.
Itai Cohen is an Assistant Professor in the Department of Physics, Laura Harrington is an Associate Professor of Entomology and Ronald Hoy is a Professor in the Department of Neurobiology and Behavior.