Neuromuscular patterns and the origin of trophic specialization in fishes.

The pattern of muscle electrical activity in the pharyngeal muscles of the mollusc-eating sunfish Lepomis microlophus is highly specialized in comparison with the pattern displayed by most other members of the sunfish family and does not change when different prey are eaten. The closest genealogical relative of this species has the specialized muscle activity pattern for crushing prey when it feeds on snails but uses the primitive sequence of muscle activity during swallowing of other prey. The ability of species that crush snails to use molluscan prey effectively is due primarily to the evolutionary transformation of the neuromuscular program controlling the trophic apparatus.