title: The epipharyngeal sensilla of the damselfly Ischnura elegans (Odonata, Coenagrionidae).
abstract: The knowledge on Odonata adult mouthparts sensilla is scanty and, notwithstanding the epipharynx in the labrum is considered an organ of taste, no ultrastructural investigation has been performed so far on this structure in Odonata. The labrum of the adult of the damselfly Ischnura elegans (Odonata, Coenagrionidae) shows on its ventral side the epipharynx with sensilla represented by articulated hairs and by small pegs located at the apex of slightly raised domes. Under scanning and transmission electron microscope, the articulated hairs, with a well developed socket and tubular body, have the typical structure of bristles, the most common type of insect mechanoreceptors, usually responding to direct touch; the pegs, showing an apical pore together with a variable number of sensory neurons (from two to five), the outer dendritic segments of which show a dendrite sheath stopping along their length, have features typical of contact chemoreceptors.
authors: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto, 06121 Perugia, Italy. Electronic address: manuela.rebora@unipg.it.
authors: Manuela
authors: M
authors: Rebora
authors: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto, 06121 Perugia, Italy.
authors: Elda
authors: E
authors: Gaino
authors: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto, 06121 Perugia, Italy.
authors: Silvana
authors: S
authors: Piersanti
mesh_terms: D000818:Animals; D002628:Chemoreceptor Cells / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D063191:Odonata / Q000648:ultrastructure*; D058618:Sensilla / Q000648:ultrastructure*; D011984:Sensory Receptor Cells / Q000648:ultrastructure
keywords: Aquatic insects; Chemoreceptors; Gustatory sensilla; Mechanoreceptors; Mouthparts