Fruit flies are a common research animal in neuroscience studies because of their surprising similarities to humans. Their behavioural and genetic similarities to humans have been well mapped by the scientific community, making them good models for studying a range of human conditions.
These include signs of anxiety, stress and disease, meaning flies can be used to study both physical and mental human diseases. They can also be used to gain insights into common behaviours, such as socialising and sleeping.
However, studying these conditions in flies usually requires expensive custom equipment that can only study a small number of flies at once. Now, researchers at Imperial College London have invented a cheap, easy-to-use and customisable piece of equipment for the rapid study of flies.
In a study published today in PLoS Biology, the team present their invention: the ethoscope. Ethoscopes combine a small Raspberry Pi computer with a camera, allowing for simultaneous recording and classification of fly behaviour.
Automatic fly monitoring
Studies on fly activity usually involve researchers looking at recorded video and manually recording each fly’s movements. Ethoscopes can do this automatically, saving researchers time.
As well as simply recording the fly’s behaviour, the ethoscope can also be customised to manipulate the behaviour of the fly, allowing researchers to study their responses. For example, the team at Imperial have used custom ethoscopes to study sleep deprivation.
The machine detected when a fly had been completely still for 20 seconds and then rotated the tube that the fly was kept in in order to wake it up. This method is considered more reliable than methods that constantly shake or tilt groups of files, whether or not they are sleeping to begin with.
The ethoscope could be customised for a range of different scenarios. PhD student Quentin Geissmann, from the Department of Life Sciences at Imperial, who led the study, said: “We can programme the machine to send stimuli to the flies only when they behave in a certain way, for example the robots can be programmed to give flies rewards only if they complete a learned task.
“It may appear surprising, but fruit flies are smart animals and they can do pretty much everything humans do: flies know how to look for food, shelter and mating partners; they learn to avoid predators and aggressive mates; they communicate, court and engage in social lives.”
Head of the lab, Dr Giorgio Gilestro, said: “The ethoscope is going to provide neuroscientists with a very new powerful tool to study, for instance, the biology of learning and memory or the function of sleep.”
Build it yourself
The ethoscopes used by the team are 3D printed, but they can be made out of folded card or paper and even LEGO bricks. The additional computer components – the Raspberry Pi and Arduino board – are cheap and easily accessible, and all software and construction specifications are freely available online.
The team have been refining their ethoscope technologically for seven years, and now use them regularly in their own research. Dr Gilestro said: “The interdisciplinary environment found at Imperial was really instrumental for this type of work. There are not many places in the world were biologists and engineers can influence each other’s work in such a powerful and productive manner.”
Source : Imperial College London