Social influences on communication signals: From honesty to exploitation

Overview Communication is at the core of understanding sociality as an interface between behaviours and phenotypes, and their evolutionary trajectories. Central to communication research is gaining an understanding of the information content of signals and the ecological, social and physiological factors that influence their format. It is clear that individuals which benefit from social exchange can critically influence what information is transmitted, how it is transmitted and whether it is scrambled to prevent eavesdropping. Less clear is how the physical channels through which signals are emitted and received might influence the extent to which they are prone to errors, dishonesty and manipulation. Here we show how sensory systems, perceptual physiology, cognitive decision rules and evolutionary trajectories produce the broad range of signalling modalities and contents that we see in nature. Our overview suggests that experimental evidence on the meaning, honesty and selective benefits of communication for signallers and receivers across invertebrates and vertebrates can provide a taxonomically broad but conceptually similar set of examples. This is not surprising, since studies across diverse lineages have demonstrated that the mechanism and function of communication systems both critically shape social behaviour and are being shaped by sociality. In particular, functional investigations of the sensory systems of vocal communication in songbirds, visual signals in trap-building predators, and chemical signalling in arthropods, have established clear examples of the limits to perception and discrimination of signal design.