28 August 2008
The most sophisticated flying device
DLH
Michael Dickinson reports on “a marvelous machine”: ——————-
Flies In Danger Escape With Safety Dance
” . . .Dickinson used superslow-motion video cameras to study how a fly avoids getting swatted.. . .Dickinson says a fly will typically jump off the surface and then begin to fly away from the swatter. But the high-speed cameras revealed something amazing about what happened before the fly jumped.
“They perform an elegant little ballet with their legs,” says Dickinson. “They move their legs around to reposition their bodies so that when they do jump, they will push themselves away from the looming threat.”
That ballet appears to give them a critical edge in escaping the swatter.
Dickinson says what’s remarkable about this body position is how fast it happens. In less than a 10th of a second, the fly has to perceive the threat using its eyes, determine what direction it’s coming from, and then make the appropriate movement with its legs so it jumps in the right direction. And all this is accomplished by a brain that’s the size of a poppy seed. . . .
. . .in my lab you really see a marvelous machine, arguably the most sophisticated flying device on the planet. . . .”
See:Michael Dickinson, Current Biology, Aug. 28, 2008
See fly flight videos:
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1
bFast
08/29/2008
12:09 am
Ooooh, stop the presses! New thread, somebody? See: http://www.livescience.com/hea.....rigin.html, it seems that sponges don’t have nerve cells, but they know how to grow ‘em. This smacks very loudly of front-loading.
2
DLH
08/29/2008
10:45 am
Michael Dickinson, Visually Mediated Motor Planning in the Escape Response of Drosophila,
Current Biology, Aug. 28, 2008
Abstract
3
reluctantfundie
08/29/2008
11:15 am
Wow.
4
Larry Fafarman
08/30/2008
7:41 am
It is also believed that flies respond to air movement created by a moving swatter. Supposedly one of the reasons for perforating swatters (some swatters are made of metal screens) is to reduce this air movement — another reason is to enable the swatter to move more quickly by reducing air resistance.
DLH (#2), citing an abstract, says,
Using high-speed videography, we found that approximately 200 ms before takeoff,
This 200 ms — or two-tenths of a second — differs from the “less than a 10th of a second” given in the other report.
IMO 1-2 tenths of a second is too slow to respond to a swatting motion of a flyswatter, so IMO this safety dance would not apply to escape from a flyswatter but would apply to escape from natural enemies. In the case of a flyswatter, IMO what is important in escape is that the fly jumps away in any direction. Many of the natural predators of flies — e.g., birds, bats, and insects — catch flies in the air or lie in wait, and in those situations this “safety dance” trait wouldn’t help. Also, IMO it would be interesting to see if flies respond to sudden air movement alone.
Questions may be sent to one of the researchers, Michael H. Dickinson, at flyman@caltech.edu
Cockroaches can detect any movement in their surroundings — cockroaches will freeze up when I enter a room.
5
Charlie
08/30/2008
1:41 pm
Speaking of flies, don’t forget this one from last year on the possibility of free will in fruit flies.
http://www.sciencedaily.com/re.....071806.htm
6
Larry Fafarman
08/30/2008
11:05 pm
Speaking of dancing insects, what about the dancing of bees? Bees perform dances that tell other bees the direction and distance of food sources — see
http://www.polarization.com/bees/bees.html
7
Charlie
08/31/2008
12:51 am
Hey LArry,
They can even learn foreign languages.
http://www.theage.com.au/natio.....-2lw8.html