Is sociality required for the evolution of communicative complexity? Evidence weighed against alternative hypotheses in diverse taxonomic groups

Abstract

Complex social communication is expected to evolve whenever animals engage in many and varied social interactions; that is, sociality should promote communicative complexity. Yet, informal comparisons among phylogenetically independent taxonomic groups seem to cast doubt on the putative role of social factors in the evolution of complex communication. Here, we provide a formal test of the sociality hypothesis alongside alternative explanations for the evolution of communicative complexity. We compiled data documenting variations in signal complexity among closely related species for several case study groups-ants, frogs, lizards and birds-and used new phylogenetic methods to investigate the factors underlying communication evolution. Social factors were only implicated in the evolution of complex visual signals in lizards. Ecology, and to some degree allometry, were most likely explanations for complexity in the vocal signals of frogs (ecology) and birds (ecology and allometry). There was some evidence for adaptive evolution in the pheromone complexity of ants, although no compelling selection pressure was identified. For most taxa, phylogenetic null models were consistently ranked above adaptive models and, for some taxa, signal complexity seems to have accumulated in species via incremental or random changes over long periods of evolutionary time. Becoming social presumably leads to the origin of social communication in animals, but its subsequent influence on the trajectory of signal evolution has been neither clear-cut nor general among taxonomic groups.

Sociality and health: impacts of sociality on disease susceptibility and transmission in animal and human societies

“…These categories cannot be easily transferred to most vertebrates, because the latter lack many of the traits (e.g. reproductive division of labour and cooperative brood care) underlying this classification scheme [30][31][32][33]. Psychologists and others studying human behaviour, on the other hand, are mainly referring to particular patterns of social relationships when qualifying aspects of social behaviour; this was used, for example, in an influential definition by Wilson [34], who characterized a species as social if it was group living and exhibited 'reciprocal communication of a cooperative nature'.…”

Sexual Selection and the Evolution of Complex Color Patterns in Dragon Lizards

“…Identifying the selective forces that drive the evolution of complex signals is a currently a focus of much research (for recent overviews see Hebets 2011; Ord and Garcia‐Porta 2012). From an interspecific perspective, many studies have focused on acoustic signals and visual behavioral displays and used intuitive measures of complexity such as repertoire size (e.g., Read and Weary 1992; Ord et al 2001).…”

The role of acoustic signaling for spacing and group coordination in a nocturnal, pair‐living primate, the western woolly lemur (Avahi occidentalis)

“…The phylogenetic hypothesis (e.g., Harvey and Pagel, 1991;Ord and Garcia-Porta, 2012) argues that signal complexity between closely related members of a taxonomic group is more similar than between more distantly related taxonomic groups, based on the shared evolutionary history. Comparable bioacoustic data to our study in nocturnal woolly lemurs are available from the nocturnal sportive lemurs of the taxonomic family Lepilemuridae, which are considered as pair-living (Rasoloharijaona et al, 2003;Rasoloharijaona et al, 2006;M endez-C ardenas and Zimmermann, 2009) and from the diurnal indris and sifakas (Pollock, 1975;Petter and Charles-Dominique, 1979;Macedonia and Stanger, 1994;Maretti et al, 2010;Patel and Owren, 2012) of the same taxonomic family (Indriidae), the former with the same (pair-living), the latter with a more complex social system (living in cohesive groups).…”