Lateral line morphology, sensory perception and collective behaviour in African cichlid fish

The lateral line system of fishes provides cues for collective behaviour, such as shoaling, but it remains unclear how anatomical lateral line variation leads to behavioural differences among species. Here we studied associations between lateral line morphology and collective behaviour using two morphologically divergent species and their second-generation hybrids. We identify collective behaviours associated with variation in canal and superficial lateral line morphology, with closer proximities to neighbouring fish associated with larger canal pore sizes and fewer superficial neuromasts. A mechanistic understanding of the observed associations was provided by hydrodynamic modelling of an artificial lateral line sensor, which showed that simulated canal-based neuromasts were less susceptible to saturation during unidirectional movement than simulated superficial neuromasts, while increasing the canal pore size of the simulated lateral line sensor elevated sensitivity to vortices shed by neighbouring fish. Our results propose a mechanism behind lateral line flow sensing during collective behaviour in fishes.

Automated summary

We studied two morphologically divergent species of fish and their hybrids to investigate the association between lateral line morphology and collective behavior. Our results showed that individuals with larger canal pore sizes and fewer superficial neuromasts were associated with closer proximities to neighboring fish. Hydrodynamic modeling of an artificial lateral line sensor supported these findings by demonstrating that simulated canal-based neuromasts were less susceptible to saturation during unidirectional movement, while increasing the canal pore size of the simulated lateral line sensor elevated sensitivity to vortices shed by neighboring fish. Our study proposes a mechanism behind lateral line flow sensing during collective behavior in fishes.