Pigmentation in mollusc shells exhibits an exceedingly diverse range of patterns that raises questions on the mechanisms underlying such diversity. This work introduces a new class of excitable systems, which extends the well-known FitzHugh-Nagumo model to allow for dynamic variation of the phase space. The phenomenon emerging from such a dynamic variation of the underlying excitable system is termed dynamic excitability. It is shown that the essential features of several classes of pigmentation patterns can be described through this unified framework of dynamic excitability, and that many of the patterns can be understood as the underlying excitable system dynamically switching between different unsteady states. A fast switch between two dynamic states is responsible for the emergence of some of the more complex pigmentation patterns observed in molluscan shells. The modeling suggests that dynamic excitability could be a universal mechanism underlying the large diversity of molluscan shell pigmentation patterns.

Close

PrevNext

Reuse & PermissionsView figure in article

• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 
• 

• Phase space dynamics
• Spatial modeling
• Spiking neuron models