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Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier

In termites, i.e. a major group of eusocial insects, the soldier caste exhibits specific morphological characteristics and extremely high aggression against predators. Although the genomic background is identical to the other non-aggressive castes, they acquire the soldier-specific behavioral charac...

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Autores principales: Ishikawa, Yuki, Aonuma, Hitoshi, Sasaki, Ken, Miura, Toru
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873212/
https://www.ncbi.nlm.nih.gov/pubmed/27196303
http://dx.doi.org/10.1371/journal.pone.0154230
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author Ishikawa, Yuki
Aonuma, Hitoshi
Sasaki, Ken
Miura, Toru
author_facet Ishikawa, Yuki
Aonuma, Hitoshi
Sasaki, Ken
Miura, Toru
author_sort Ishikawa, Yuki
collection PubMed
description In termites, i.e. a major group of eusocial insects, the soldier caste exhibits specific morphological characteristics and extremely high aggression against predators. Although the genomic background is identical to the other non-aggressive castes, they acquire the soldier-specific behavioral character during the course of caste differentiation. The high aggressiveness and defensive behavior is essential for colony survival, but the neurophysiological bases are completely unknown. In the present study, using the damp-wood termite Hodotermopsis sjostedti, we focused on two biogenic amines, octopamine (OA) and tyramine (TA), as candidate neuromodulators for the defensive behavior in soldiers. High-performance liquid chromatographic analysis revealed that TA levels in the brain and suboesophageal ganglion (SOG) and the OA level in brain were increased in soldiers than in pseudergates (worker caste). Immunohistochemical analysis revealed that TA/OA neurons that innervate specific areas, including the mandibular muscles, antennal nerve, central complex, suboesophageal ganglion, and thoracic and/or abdominal ganglia, were enlarged in a soldier-specific manner. Together with the results that pharmacological application of TA promoted the defensive behavior in pseudergates, these findings suggest that the increased TA/OA levels induce the higher aggressiveness and defensive behavior in termite soldiers. The projection targets of these soldier-specific enlarged TA/OA neurons may have important roles in the higher aggressiveness and defensive behavior of the termite soldiers, inducing the neuronal transition that accompanies external morphological changes.
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spelling pubmed-48732122016-06-09 Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier Ishikawa, Yuki Aonuma, Hitoshi Sasaki, Ken Miura, Toru PLoS One Research Article In termites, i.e. a major group of eusocial insects, the soldier caste exhibits specific morphological characteristics and extremely high aggression against predators. Although the genomic background is identical to the other non-aggressive castes, they acquire the soldier-specific behavioral character during the course of caste differentiation. The high aggressiveness and defensive behavior is essential for colony survival, but the neurophysiological bases are completely unknown. In the present study, using the damp-wood termite Hodotermopsis sjostedti, we focused on two biogenic amines, octopamine (OA) and tyramine (TA), as candidate neuromodulators for the defensive behavior in soldiers. High-performance liquid chromatographic analysis revealed that TA levels in the brain and suboesophageal ganglion (SOG) and the OA level in brain were increased in soldiers than in pseudergates (worker caste). Immunohistochemical analysis revealed that TA/OA neurons that innervate specific areas, including the mandibular muscles, antennal nerve, central complex, suboesophageal ganglion, and thoracic and/or abdominal ganglia, were enlarged in a soldier-specific manner. Together with the results that pharmacological application of TA promoted the defensive behavior in pseudergates, these findings suggest that the increased TA/OA levels induce the higher aggressiveness and defensive behavior in termite soldiers. The projection targets of these soldier-specific enlarged TA/OA neurons may have important roles in the higher aggressiveness and defensive behavior of the termite soldiers, inducing the neuronal transition that accompanies external morphological changes. Public Library of Science 2016-05-19 /pmc/articles/PMC4873212/ /pubmed/27196303 http://dx.doi.org/10.1371/journal.pone.0154230 Text en © 2016 Ishikawa et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Ishikawa, Yuki
Aonuma, Hitoshi
Sasaki, Ken
Miura, Toru
Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier
title Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier
title_full Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier
title_fullStr Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier
title_full_unstemmed Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier
title_short Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier
title_sort tyraminergic and octopaminergic modulation of defensive behavior in termite soldier
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873212/
https://www.ncbi.nlm.nih.gov/pubmed/27196303
http://dx.doi.org/10.1371/journal.pone.0154230
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