Fruit flies see through a unique combination of photoreceptor movements and light sensitivity. The photoreceptors accomplish this by responding to light changes with ultrafast, mirror-symmetrical movements called photoreceptor microsaccades. So, when the fly moves forward, they are gathering images that both move with the world and against it simultaneously.
This process can be broken down further:
- Photoreceptors: These are specialized cells in the fruit fly's eye that are sensitive to light. They convert light into electrical signals that the brain can interpret.
- Microsaccades: These are tiny, rapid movements of the photoreceptors. They occur in a mirror-symmetrical fashion.
- Image Gathering: As the fruit fly moves, these microsaccades allow the fly to gather visual information in two ways. Some images move with the world, and some move against it. This is key to depth perception and object recognition.
In essence, fruit flies don't just see a static image; they actively sample their visual environment using these specialized photoreceptor movements to build a dynamic representation of the world around them. This makes their vision efficient and adaptable despite their small size.
