Flies walk on air in levitation experiment
Posted by Xeno on January 5, 2012
The technique, known as ”diamagnetic levitation”, allows water and organic based materials to become weightless.
Floating freely inside a plastic tube, the flies were observed closely to spot any changes in their behaviour.
The scientists confirmed effects previously seen in similar experiments in Earth orbit. The flies walked more quickly and more frequently while floating in zero gravity than they did on the ground.
Previously it was not clear whether the changing G-forces associated with space flight may have affected the flies.
The research is published today in the Journal of the Royal Society Interface.
Author Dr Richard Hill, from the University of Nottingham, and colleagues wrote: ”This study shows that the walking speed of fruit flies and their ‘activity’ is altered significantly by counteracting gravitational force.
”Diamagnetic levitation enabled us to maintain tight control over the experimental conditions of all the experimental subjects. This allowed us to identify, unambiguously, the alteration of effective gravity as the cause of the anomalous behaviour.
”Four billion years of evolution have equipped life on Earth to withstand the stresses generated by the ever-present pull of gravity. Here, we have shown that diamagnetic levitation can be used to investigate directly the influence of changing gravity on the locomotion of a complex multi-cellular organism, and that close comparison can be made with experiments performed in space.”
Most biological materials are “diamagnetic,” Richard Hill, the study’s lead author, said. “This is a different type of magnetism from what we’re familiar with,” explained Hill, who is a physicist at the University of Nottingham in England. “What we ordinarily think of as ‘magnetic materials’ are ferromagnetic materials such as iron — these are strongly attracted by magnetic fields.  Magnetic fields have been used in previous studies to levitate organic materials, as well as small living organisms and even a live frog. “Diamagnetic material is weakly repelled from magnetic fields, compared with the more commonly known ‘magnetic’. materials such as iron, which are strongly attracted to a magnetic field,” the scientists wrote.  Magnetic fields have been previously been used in a range of experiments to levitate organic materials, as well as small living organisms, including a frog, grasshoppers and fish. 
Scientists have used magnetic fields to ‘levitate’ flies in the first weightless tests conducted outside space.