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Isotocin neuronal phenotypes differ among social systems in cichlid fishes.

Authors :
Reddon AR
O'Connor CM
Nesjan E
Cameron J
Hellmann JK
Ligocki IY
Marsh-Rollo SE
Hamilton IM
Wylie DR
Hurd PL
Balshine S
Source :
Royal Society open science [R Soc Open Sci] 2017 May 17; Vol. 4 (5), pp. 170350. Date of Electronic Publication: 2017 May 17 (Print Publication: 2017).
Publication Year :
2017

Abstract

Social living has evolved numerous times across a diverse array of animal taxa. An open question is how the transition to a social lifestyle has shaped, and been shaped by, the underlying neurohormonal machinery of social behaviour. The nonapeptide neurohormones, implicated in the regulation of social behaviours, are prime candidates for the neuroendocrine substrates of social evolution. Here, we examined the brains of eight cichlid fish species with divergent social systems, comparing the number and size of preoptic neurons that express the nonapeptides isotocin and vasotocin. While controlling for the influence of phylogeny and body size, we found that the highly social cooperatively breeding species ( n  = 4) had fewer parvocellular isotocin neurons than the less social independently breeding species ( n  = 4), suggesting that the evolutionary transition to group living and cooperative breeding was associated with a reduction in the number of these neurons. In a complementary analysis, we found that the size and number of isotocin neurons significantly differentiated the cooperatively breeding from the independently breeding species. Our results suggest that isotocin is related to sociality in cichlids and may provide a mechanistic substrate for the evolution of sociality.<br />Competing Interests: The authors declare no competing interests.

Details

Language :
English
ISSN :
2054-5703
Volume :
4
Issue :
5
Database :
MEDLINE
Journal :
Royal Society open science
Publication Type :
Academic Journal
Accession number :
28573041
Full Text :
https://doi.org/10.1098/rsos.170350