Antennal movements and mechanoreception: neurobiology of active tactile sensors

Staudacher E, Gebhardt MJ, Dürr V. Antennal movements and mechanoreception: neurobiology of active tactile sensors. Advances in Insect Physiology. 2005;32:49-205.Insect antennae are multisensory probes which are used in many behavioural contexts, receiving sensory information from various modalities. Mechanoreceptors signal exteroreceptive cues like contact with another surface, flow or vibration of the surrounding medium, and proprioreceptive cues like joint angles and cuticular strain due to bending. Antennae can actively search the surrounding space, scan objects for surface properties, or transfer information between conspecifics by means of physical contact. We review insect behaviours involving antennal mechanosensory information, and passive or active antennal movements. Chemo- and thermoreception are only covered to the extent to which there is a direct connection to tactile sensing. Particular emphasis is given to model systems of invertebrate neuroscience, i.e. cockroach, cricket, locust, stick insect and the honeybee. For comparison, corresponding behaviours of crayfish and lobsters are discussed. The six sections deal with (a) the antennal motor system, kinematics, biomechanics, musculature and efferent innervation; (b) the sensory physiology of antennal mechanoreceptors, including mechanosensitive hairs, campaniform sensilla, chordotonal organs and stretch receptors; (c) the neuroanatomy of the brain structures processing antennal mechanosensory information, notably the deutocerebrum; (d) the neurophysiology of the afferents, local and descending interneurons, and motoneurons; (e) the behavioural physiology of passive and active sensing, including reflex behaviours, graviception, steering, escape, tactile exploration and localisation, pattern recognition, tactile learning and communication; and (f) some engineering aspects regarding the construction of artificial tactile antenna