The University of Sussex

Signalling and territorial aggression: an investigation by means of synthetic behavioural ecology

Peter de Bourcier, Michael Wheeler

Intra-specific aggressive signalling is an adaptive behaviour which occurs throughout the animal kingdom. But the scientific understanding of such signalling is incomplete, partly because the relevant ecological factors are hard to isolate in highly complex natural environments. We perform a series of experiments in which populations of simulated animals (animats), with idealized sensory mechanisms, are placed in a simulated world in which there are aggressive confrontations over food. An individual animat's behaviour is determined by relatively simple relationships between the sensory information that it can pick up from its environment (including information about food and other animats) and its internal states (energy, hunger and aggression). When animats can sense the resource holding potential of other individuals within sensory range, there is evidence of a simple form of territoriality. To this ecological context, we introduce the signalling of aggressive intentions, and the possibility that some agents will be dishonest. Our analysis of subsequent experiments, in which we gradually increase the cost - in energy terms - of producing such signals, provides qualitative evidence that the handicap principle, according to which higher costs enforce honesty, can be applied to multi-agent, territorial situations. We conclude with a discussion of the scope and implications of our results.

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