Why Is it So Difficult to Swat a Fly?
The brains of flies are wired to avoid the swatter, US researchers said on Thursday.
At the mere hint of a threat, the insects adjust their preflight stance to flee in the opposite direction, ensuring a clean getaway, they said in a finding that helps explain why flies can so easily evade swipes from their human foes.
"These movements are made very rapidly, within about 200 milliseconds, but within that time the animal determines where the threat is coming and activates a set of movements to position its legs and wings," Michael Dickinson of the California Institute of Technology said in a statement.
"This illustrates how rapidly the fly's brain can process sensory information into an appropriate motor response," said Dickinson, whose research appears in the journal Current Biology.
Dickinson's team studies this process in fruit flies using high-speed digital imaging equipment and a fancy fly swatter.
In response to a threat from the front, the fly moves its middle legs forward, leans back and raises its back legs for a backward takeoff. If the threat is from the side, the fly leans the other way before takeoff.
The findings offer new insight into the nervous system of the fly, and lends a few clues on how to outsmart them.
Dickinson, a bioengineer, has devoted his life's work to the study of insect flight. He has built a tiny robotic fly called Robofly and a 3-D visual flight simulator called Fly-O-Vision.
The Truth about the
For many environmentalists, the world seems to be getting worse. They have developed a hit-list of our main fears: that natural resources are running out; that the population is ever growing, leaving less and less to eat; that species are becoming extinct in vast numbers, and that the planet's air and water are becoming ever more polluted.
But a quick look at the facts shows a different picture. First, energy and other natural resources have become more abundant, not less so, since the book The Limits to Growth was published in 1972 by a group of scientists. Second, more food is now produced per head of the world's population than at any time in history. Fewer people are starving. Third, although species are indeed becoming extinct, only about 0.7% of them are expected to disappear in the next 50 years, not 25-50%, as has so often been predicted. And finally, most forms of environmental pollution either appear to have been exaggerated, or are temporary-associated with the early phases of industrialisation and therefore best cured not by restricting economic growth, but by accelerating it. One form of pollution—the release of greenhouse gases that causes global warming—does appear to be a phenomenon that is going to extend well into our future, but its total impact is unlikely to pose a devastating problem.
Yet opinion polls suggest that many people nurture the belief that environmental standards are declining and many factors seem to cause this disjunction between perception and reality.