Conclusion

Various sensors enable winged insects to stabilize themselves and navigate safely in an unfamiliar environment, where obstacles may be stationary or mobile. Vision plays a key role in stabilizing and guiding the animal. Surprisingly, due to its optical characteristics, this vision is very coarse, especially in flies, in terms of resolution and contrast sensitivity. Nevertheless, it is certainly much more important for a fly to avoid obstacles and spot a fellow fly than to admire the detail of a painting or the sharpness of a photograph. The vision of flying insects is mainly dedicated to motion detection, thanks to specialized neurons called elementary motion detectors (EMDs), where it is important to have a fast photoreceptor response time and to limit measurement errors by means of low-pass spatial filtering. Motion detection is closely linked to the measurement of optic flow, which is...