ABSTRACT
Animal communication was traditionally viewed in a dyadic perspective (signaller-receiver dyad), where the evolution of signals and of perceptual systems relied on the fitness consequences for the sender and receiver (Dawkins and Krebs, 1978; Krebs and Dawkins, 1984). Under this perspective, ‘true communication’ occurs when signal detection is beneficial for both senders and receivers, ‘manipulation’ when signal detection is only beneficial for the sender, and ‘exploitation’ when only the receiver gains by detecting the signal (Bradbury and Vehrencamp, 1998). However, this has been recognised as a simplistic approach to understand communication systems and their evolution, since wherever signals travel further than the average spacing between two individuals, there is a
potential for a communication network to exist, including the provision of information to unintended receivers (McGregor and Peake, 2000; McGregor, 2005). Therefore, true communication can be defined as the provision of information by a sender who produces a sensory stimulus or signal to one or more receivers that then respond in a way that is beneficial to both sender and receivers. In this case, signallers and receivers form a mutualism in which signals co-evolve with the sensory biology of receivers. Once established, mutually beneficial communication relationships could be susceptible to deceitful manipulations by signallers, which reduce the receiver fitness, and signal interception by unintended receivers (including predators and conspecifics), the response of which to the stimulus may impose fitness costs to the sender (see Searcy and Nowicki, 2005, for insightful discussion).
