The scolopidial accessory organs and Nebenorgans in orthopteroid insects: Comparative neuroanatomy, mechanosensory function, and evolutionary origin. Issue 6 (November 2017)

• Record Type: Journal Article
• Authors: Strauß, Johannes
• Is Part Of: Arthropod structure & development. Volume 46:Issue 6(2017:Nov.)
• Page Start: 765
• Page End: 776
• Publication Date: 2017-11
• Subjects: Mechanosensory organ -- Sensory evolution -- Neuroanatomy -- Chordotonal organ -- Accessory organ -- Nebenorgan -- Insect; Arthropoda -- Morphology -- Periodicals; Arthropoda -- Anatomy -- Periodicals; Arthropoda -- Cytology -- Periodicals; Arthropods -- growth & development -- Periodicals; 595
• DOI: 10.1016/j.asd.2017.08.004
• Languages: English
• ISSNs: 1467-8039

Abstract

Abstract: Scolopidial sensilla in insects often form large sensory organs involved in proprioception or exteroception. Here the knowledge on Nebenorgans and accessory organs, two organs consisting of scolopidial sensory cells, is summarised. These organs are present in some insects which are model organisms for the physiology of mechanosensory systems (cockroaches and tettigoniids). Recent comparative studies documented the accessory organ in several taxa of Orthoptera (including tettigoniids, cave crickets, Jerusalem crickets) and the Nebenorgan in related insects (Mantophasmatodea). The accessory organ or Nebenorgan is usually a small organ of 8–15 sensilla located in the posterior leg tibia of all leg pairs. The physiological properties of the accessory organs and Nebenorgans are so far largely unknown. Taking together neuroanatomical and electrophysiological data from disparate taxa, there is considerable evidence that the accessory organ and Nebenorgan are vibrosensitive. They thus complement the larger vibrosensitive subgenual organ in the tibia. This review summarises the comparative studies of these sensory organs, in particular the arguments and criteria for the homology of the accessory organ and Nebenorgan among orthopteroid insects. Different scenarios of repeated evolutionary origins or losses of these sensory organs are discussed. Neuroanatomy allows to distinguish individual sensory organs for analysis of sensory physiology, and to infer scenarios of sensory evolution. Highlights: Nebenorgans occur in cockroaches and heelwalkers; accessory organs in Ensifera They are compact scolopidial organs with 4–17 sensilla. The location closely underneath the leg cuticle suggest a vibrosensitive function. This is supported by sensory afferents terminating in the main mechanosensory areal. Neuroanatomy is used to reveal the diversification and homology of sensory organs.