One of the nice things about working with flies is that you can build a simple, cost-efficient tracking system pretty easily. In the lab we’ve built both inexpensive and expensive tracking systems, and the price differences largely come from the type of camera and building materials you use.
First, you want to build an arena appropriate to track the flies (more on that in ‘What materials should I use to build behavior arenas?’ and ‘What are the best dimensions for a behavior arena?’)
Second, you want to decide on a camera. There are many different types of cameras that you can buy. Here are a few that we have used with some general ideas on best use:
If you have money and want high quality: Pointgrey
If you just need something basic to track bodies moving around: USB cameras
If you want a shorter focal distance, here are Lenses for USB cameras
If you need an IR camera - you can just add a homemade or IR filter over a regular USB camera
Third, you want to build a backlight. Since bright light can affect fly behavior, we tend to use IR cameras with an IR backlight. We typically use a Pointgrey or USB Camera with an IR filter over the camera and build an IR array as a backlight.
How do you build an IR array?
Identify the area of interest that needs lighting up. Make sure that the light is uniformly and evenly distributed under or over the area of interest.
Use an LED array calculator to find the best circuit array option for your set up:
Solder your LED array on the PCB boards
Once your array is finished, you can add a BuckPuck or BuckBlock DC LED Driver with dimmer option to assure the constant current delivery in your array and to control the brightness in your LEDs.
Connect it to a stand alone power supply.
Fourth, you want to add a control for your tracking system. Arduino is one of the common controllers that is used to run and automate LED arrays for the tracking camera, Optogenetic elements (LEDs) and any other solenoid valves, etc that need to be controlled by Matlab or Python.
Fifth, set up your tracking software. There are many tracking softwares available to use. For a quick comparison of some of the fly tracking software out there, check out “Which tracking system should I use?”.
FlyGrAM: a simple tracking system: We’ve developed and uploaded here a building manual for a simple tracking system that we call flyGrAM (fly Group Activity Monitor) that we use to track flies in the lab and in the classroom. This building manual has all of the info about items you need and how to put them together:
If you want details on how to run experiments and analyze data using this apparatus, you can find that at “Methods for Exploring the Circuit Basis of Ethanol-Induced Changes in Drosophila Group Locomotor Activity”.
To download the free software that tracks and plots activity of flies go to the Kaun Lab Github.