Video: Patterns displayed in a wind tunnel allow scientists to control the movement of an untethered fly
Life for lab flies just got more interesting, thanks to an interactive virtual-reality system developed by Swiss and US researchers.
They have built a wind tunnel for flies with changing scenes or images projected onto its walls. A camera tracks the fly in 3D, making the images move in response to it flying around inside.
The VR system offers a new way to gain insight into how flies鈥� visual environment affects how they move and behave. The researchers say that they hope to build VR setups for other animals too.
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Engineers building small, flapping aircraft (with video) already try to borrow visual processing tricks used by flying insects. Improved knowledge of how insects use visual stimuli would help further.
Off the leash
鈥淥ur research is relevant to that because biologists are currently not producing enough functional understanding because they are not looking at free flight with the right tools,鈥� says lead researcher from the Institute of Neuroinformatics, Zurich, Switzerland.
Previous setups have presented flies with changing images but involved tethering the fly and could not change the images in response to its movements. 鈥淭hat is very unnatural and it becomes very difficult to interpret the data because of the strong interference by the experimenter,鈥� explains Fry.
But 鈥渋f you do behavioural experiments with an animal that鈥檚 running or flying around it鈥檚 very hard to control the experiment,鈥� he adds
The researchers are most interested in understanding how fruit flies respond to 鈥渙ptic flow鈥� 鈥� the perception of the environment moving caused by the fly鈥檚 own motion. Seeing scenery speed by when you look out of a car window is an example of optic flow.
Bar flies
Fruit flies measure and adjust their speed using optic flow, and the team found that, using the VR system, a fruit fly鈥檚 flight could be controlled by moving a pattern of bars on the walls.
The researchers showed that they could control the fly鈥檚 speed, or even make it hover, by making the insect think it was moving faster or slower than it really was.
鈥淭his programme defines how the world reacts to the fly鈥檚 behaviour,鈥� says Fry. 鈥淵ou gain access to information you just wouldn鈥檛 get without the tools, because you can control a fly that is immersed in a virtual environment.鈥�
In future, the team plans to project more naturalistic patterns on the walls of the tunnel, to gain more detailed insights into how flies react to their environment.
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