Evolving Nonapeptide Mechanisms of Gregariousness and Social Diversity in Birds

• Type of Material: Article
• Authors: James L. Goodson, Indiana University; Aubrey M. Kelly, Emory University; Marcy A. Kingsbury, Indiana University
• Language: English
• Date: 2012-01-13
• Publisher: Elsevier
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2012 Elsevier Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): https://doi.org/10.1016/j.yhbeh.2012.01.005
• Title of Journal or Parent Work: Hormones and Behavior
• Volume: 61
• Issue: 3
• Start Page: 239
• End Page: 250
• Grant/Funding Agency: NIMH
• Grant/Funding Information: Support for much of the work reviewed here has been provided by the NIMH.
• Keywords: aggression; arginine vasopressin; coloniality; territoriality; mesotocin; sociality; arginine vasotocin; isotocin; pair bonding; hypothalamus; bird; flocking; paraventricular nucleus; oxytocin; evolution; finch; bed nucleus of the stria terminalis

Abstract

Of the major vertebrate taxa, Class Aves is the most extensively studied in relation to the evolution of social systems and behavior, largely because birds exhibit an incomparable balance of tractability, diversity, and cognitive complexity. In addition, like humans, most bird species are socially monogamous, exhibit biparental care, and conduct most of their social interactions through auditory and visual modalities. These qualities make birds attractive as research subjects, and also make them valuable for comparative studies of neuroendocrine mechanisms. This value has become increasingly apparent as more and more evidence shows that social behavior circuits of the basal forebrain and midbrain are deeply conserved (from an evolutionary perspective), and particularly similar in birds and mammals. Among the strongest similarities are the basic structures and functions of avian and mammalian nonapeptide systems, which include mesotocin (MT) and arginine vasotocin (VT) systems in birds, and the homologous oxytocin (OT) and vasopressin (VP) systems, respectively, in mammals. We here summarize these basic properties, and then describe a research program that has leveraged the social diversity of estrildid finches to gain insights into the nonapeptide mechanisms of grouping, a behavioral dimension that is not experimentally tractable in most other taxa. These studies have used five monogamous, biparental finch species that exhibit group sizes ranging from territorial male-female pairs to large flocks containing hundreds or thousands of birds. The results provide novel insights into the history of nonapeptide functions in amniote vertebrates, and yield remarkable clarity on the nonapeptide biology of dinosaurs and ancient mammals.