How do Crabs Control their Muscle Receptors?

Abstract

Like crayfish, lobsters and other Decapod Crustacea, crabs are well endowed with proprioceptors and other mechanoreceptors in their walking legs and chelipeds (Bush & Laverack, 1982). These include joint receptors (chordotonal organs), muscle receptors and tendon (or apodeme) tension receptors, all to some extent functionally analogous with the corresponding sense organs in vertebrates. As in other animals, only the muscle receptors have an efferent innervation. This is comparable to the motor supply of the best known crustacean proprioceptors, the abdominal muscle receptor organs (MROs) of lobsters and crayfish (Fields, 1976).The limb muscle receptors, however, lack any peripheral inhibitory control upon the sensory neurones themselves, of the kind exerted by the ‘accessory nerves’ of the abdominal MROs.