Digging in sand crabs: coordination of joints in individual legs.

摘要: Sand crabs use their multi-jointed legs to dig into sand. Combined movement and electromyogram (EMG) analyses showed that the pattern of intra-leg coordination in two sand different families (Blepharipoda occidentalis Emerita analoga) is similar 2 3, but very leg 4. For example, sequence proximal joint movements 3 elevation, retraction, depression protraction (similar backward walking most decapods), 4 protraction, retraction forward walking). The synergies are same during sea water sand, suggesting motor programme used both situations. At transition from however, frequency amplitude EMG potentials increase, phasing output (and presumably 3) changes proportional (both power return strokes co-vary with period) stroke constant (power much more period than do strokes). remains intermediate between On basis segmental specialisation patterns for legs, we hypothesize crab digging may be an evolutionary mosaic disparate ancestral locomotor behaviours.