Flykeeper
Keep a fly whose behaviour comes from a live simulation of a real fruit fly brain, running on your phone.
Flykeeper simulates the FlyWire connectome of an adult fruit fly, 138,584 neurons and 3,732,460 connections, on your iPhone, and lets the fly walk, groom, eat and sleep from the spikes. You feed it, touch it and watch its brain light up in 3D. It has no account and no networking code.
Submitted to the App Store, in review · iPhone · Free
What it does
A real connectome, simulated live
FlyWire FAFB v783, published in Nature in 2024, stepped as leaky integrate-and-fire neurons at 1 ms in a Rust engine on the phone. The screen shows the real neuron count, connection count and simulation steps per second.
Feed, touch, lights out
Drop food and the 786 dopamine neurons the connectome identifies light up while it eats; a tap fires the mechanosensory input; lights out lets it sleep. A hungry fly runs slower and grooms instead of walking.
The brain in 3D
Every neuron is a point at its true coordinates, coloured by firing rate, with 8,000 cells drawn with their real branches. Rotate and pinch to zoom; fast-forward 4x, 16x or 64x.
The eye
Optional: the camera drives the fly's 10,629 simulated photoreceptors. Frames are sampled and dropped, never recorded or sent.
Honest about what is measured
The wiring is measured; what a firing pattern means (for example 7% of cells firing reads as 'turn') is the app's own reading, and the app says so on screen.
Privacy
Flykeeper collects nothing and makes no network requests. The only thing it stores is your fly's state (hunger, rest, mood) in the app's own storage, and the camera is used only if you turn on the Eye.
- Account: none. The app has no sign-in and no account.
- Reaches us: nothing
FAQ
Is it really a fly brain?
The wiring is: FlyWire FAFB v783, 138,584 neurons and 3,732,460 connections mapped from an adult female fruit fly (Dorkenwald et al. and Schlegel et al., Nature 2024, CC BY 4.0). How a firing pattern turns into walking or turning is the app's interpretation, and the app labels it that way.
Will it slow down my phone?
There are three brain sizes: a small synthetic one for phones that must not stutter, and two views of the real connectome at different connection strengths.
Does it need the internet?
No. The connectome ships inside the app and the app makes no network requests, so it works in airplane mode.
Is the code open?
Yes, MIT-licensed at github.com/fortunto2/flykeeper; the connectome data is CC BY 4.0.