The evolution of sociality, vocal signals and of their perception

This is a comparative approach studying both phylogenetically close (starlings in South Africa and caciques in Guiana) and distant species, that led to an International associated laboratory France/South Africa since 2015, involving 7 EthoS staff members from the three teams and three South-African universities. To our knowledge, no large study integrates a thorough and detailed study of social and behavioural characteristics of targeted species belonging to different phylogenetic groups to a large phylogenetical approach of vocal signals' structure.

Evolution of vocal communication

Phylogenetic approach of vocal signal structures

This is precisely the ambition of this project for which we plan to test the same questions with a set of species within distinct phylogenetical groups (songbirds: sturnids and Cossypha African species; non-songbirds such as kingfishers and galliforms (Coll Eq 1); but also some mammal species, Coll Eq 3). All these groups present some level of sociality or, for some songbird species, "pseudosociality" (combining familiarity and territoriality). We compare species with different types of social systems, as well as populations of the same species living in different habitats or at different distances. We look at:

  1. the impact of the social system on individual and sexual distinctiveness,
  2. the relative role of phylogenetic inertia,
  3. the factors involved in the evolution of complex repertoires. The final part will be the integration of multilevel information to provide an overall model. As a first example, we can mention the finding of a clear relationship between the temporal structuring of song and the social organization with a gradient from territorial starling species using "turn taking" modalities and sturnid species forming family groups that sing in collective chorus mostly. We could show in European starlings that the use of turn taking interactions depends on the immediate social context but also on social experience during development and brain plasticity. In caciques, social structure is an important feature for the emergence of social dialects. Our approach of dialects and temporal regulations of interactions is original as it is highly integrative, thanks to the other fields of expertise of the team. Thus we can bring together functional aspects (social functions), causality (attentional processes, brain functioning), ontogeny (developmental factors) of a given species or of different species, to develop models of evolution based on this knowledge.