Social behaviour and nonapeptide binding in passerine species of the Tibetan plateau (#844)
The Tibetan plateau presents a uniquely challenging environment for passerine birds and previous studies have demonstrated that several of these endemic species display particular social behaviour and seasonally variable hormonal profiles. Within the brain nonapeptides are strongly conserved across all vertebrate taxa and are known to influence social behaviour in a species-specific way and this is thought to be due to differences in nonapeptide receptors within the brain. Differences in nonapeptide binding have been previously reported for gregarious compared to territorial bird species birds (e.g. Goodson et al. 2006) but to date no studies have directly compared free living avian species in the non-breeding season when circulating sex-steroid levels are at their lowest. We quantified aggression and collected brain tissue from wild free living white-rumped (Montifringalla taczanowski) and rufous-necked (Montifringalla ruficollis) Pere David's (Montifringilla davidiana) snowfinches in the non-breeding season in Tibet. Using simulated territorial intrusions we found that white-rumped snowfinches were more aggressive than rufous-necked snowfinches which are facultatively social. We used the [125I] ornithine vasotocin analog (125I-OVTA) to quantify and compare nonapeptide binding in the brain. The ornithine analog 125I-OVTA is widely used as a mesotocin receptor ligand but it also binds vasotocin. We found that white-rumped snow finches had higher nonapeptide binding in the lateral septum compared to rufous-necked snowfinches; no sex differences were observed in receptor density so the sexes were combined. The lateral septum forms part of the social behaviour network in the brain with a role in regulating social behaviour such as aggression and our findings thus support mounting evidence for a role of nonapeptides in non-sexual social behaviour in birds.
Research Supported by NSF International Research Fellowship OISE-0701325 to JED; NSF grant IOS-0750540 and the Endowed Chair in Physiology, University of California, Davis to JCW; BBSRC Strategic Roslin Institute funding to SLM.
- Goodson et al (2006) Neuropeptide Binding Reflects Convergent and Divergent Evolution in Species-Typical Group Sizes. Horm Behav. 50(2):223–236.