Johnston's organ
Johnston's organ is a collection of sensory cells found in the pedicel (the second segment) of the antennae in the Class Insecta.[1] Johnston's organ detects motion in the flagellum (third and typically final antennal segment). It consists of over 200 scolopidia arrayed in a bowl shape, each of which contains a mechanosensory chordotonal neuron.[2][3] The presence of Johnston's organ is a defining characteristic which separates the Class Insecta from the other hexapods belonging to the group Entognatha.
Johnston's organ can be seen in Drosophila. It consists of a sail-like flagellum which rotates in a structure called the funiculus. Air movement deforms the cuticle at the joint between segments 2 and 3 where the sensory units of Johnston’s organ attach. Johnston's organ reacts between 150 and 500 Hz. One function is for detecting the wing beat frequency of a mate.[2] The third segment can also be deformed by gravity irrespective of head orientation and this enables it to sense gravity.[1]
Johnston's organ was named after the physician Christopher Johnston,[4] father of the physician and Assyriologist Christopher Johnston.
Johnston's organ can also sense wind.[5]
[edit] References
- ^ a b Kamikouchi A, Inagaki HK, Effertz T, Hendrich O, Fiala A, Göpfert MC, Ito K. (2009).The neural basis of Drosophila gravity-sensing and hearing. Nature. 458(7235):165-71. PMID 19279630
- ^ a b Göpfert MC, Robert D. (2002). The mechanical basis of Drosophila audition. J Exp Biol. 205(Pt 9):1199-208. PMID 11948197
- ^ Yack JE. (2004). The structure and function of auditory chordotonal organs in insects. Microsc Res Tech. 63(6):315-37. PMID 15252876
- ^ Johnston, C.. Auditory Apparatus of the Culex Mosquito. Quarterly Journal of Microscopical Science, 1855, 3 (Old Series):97-102.
- ^ Yorozu S, Wong A, Fischer BJ, Dankert H, Kernan MJ, Kamikouchi A, Ito K, Anderson DJ. (2009). Distinct sensory representations of wind and near-field sound in the Drosophila brain. Nature. 458(7235):201-5. PMID 19279637
