The University of Sussex

Aggressive signaling meets adaptive receiving: further experiments in synthetic behavioural ecology

Peter de Bourcier, Michael Wheeler

This paper presents the results of our most recent investigations into the relationship between (i) aggressive communication systems, and (ii) the ecological contexts in which those systems evolve. We perform experiments in a simple synthetic ecology, in which simulated animals (animats) are in competition over food. In the first experiment, each individual has a signaling strategy, which is determined by a form of artificial evolution in which there is no explicit fitness function. We vary the cost of producing aggressive signals, and analyse the resulting population dynamics. The results indicate that the general logic of the handicap principle (according to which higher costs enforce reliability) can apply in the sort of ecological context not easily studied by formal models in theoretical biology. We then extend the model to take account of the fact that the behaviour of an animal in reaction to an incoming signal will be the result not of the signal alone, but also of the degree of importance that that receiver gives to that signal. So, to invesigate the effect of receiver tactics on aggressive communication systems, we introduce the concurrent evolution of individual signaling and receiving strategies. Variations in the cost of signaling result in notably different population dynamics. We discuss certain key features of these dynamics, with particular reference to their effect on the reliability of the signaling system.

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