Chordotonal Organ

a sensory organ of insects and crustaceans. Chordotonal organs consist of groups of elongate scolopale chordotonal sensillae drawn between two areas of the cuticle or between the cuticle and adjacent tissues. Each sensillum consists of one to three bipolar neurons and two to three auxiliary cells, one of which contains the cylindrical scolopale. Some chordotonal organs are attached to the cuticle by slender ligaments. They may be located on the antennae, mouth, legs, wings, or thorax. Most are proprioceptors, perceiving stimuli from various parts of the body and tissues, especially in the joints of the extremities or between body segments. Chordotonal organs located in the tibias of insects react to vibrations of the surface on which the insect is located, for example, soil and plants.