Form-function relationship in artificial lateral lines.

We examined the form-function relationship of laboratory-constructed artificial lateral line canals. These biomimetic flow sensors consisted of a transparent silicone bar located inside a fluid filled canal equipped with canal pores. The silicone bar guided the light from a LED towards a position- sensitive photodiode. Fluid motion inside the canal deflected the silicone bar which was detected by the photodiode. We found that the resonance frequency of the silicone bar determined the resonance frequency of the artificial lateral line (frequency at which the sensor was most sensitive). The thickness and length of the silicone bar influenced both, the resonance frequency and the sensitivity (across all tested frequencies) of the artificial lateral line sensor. Sensitivity was also influenced by the length and diameter of the artificial lateral line canals. The distance between canal pores determined the spatial resolution of the sensor. The functionality of the sensor in detecting oscillatory fluid motions remained when the canal pores were covered with flexible membranes. Tension, diameter and thickness of the membranes altered the temporal filter properties of the artificial lateral line neuromast. The density and viscosity of the fluid inside the artificial lateral line canals also influenced the sensitivity and temporal filter properties of the artificial lateral line. The acquired knowledge will allow us to optimize artificial lateral line systems for specific technical applications.