The effect of fight cost structure on fighting behaviour

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract A common feature of animal populations is the stealing by animals of resources such as food from other animals. This has previously been the subject of a range of modelling approaches, one of which is the so called "producer-scrounger" model. In this model a producer finds a resource that takes some time to be consumed, and some time later a (generally) conspecific scrounger discovers the producer with its resource and potentially attempts to steal it. In this paper we consider a variant of this scenario where each individual can choose to invest an amount of energy into this contest, and the level of investment of each individual determines the probability of it winning the contest, but also the additional cost it has to bear. We analyse the model for a specific set of cost functions and maximum investment levels and show how the evolutionarily stable behaviour depends upon them. In particular we see that for high levels of maximum investment, the producer keeps the resource without a fight for concave cost functions, but for convex functions the scrounger obtains the resource (albeit at some cost). Permanent repository link

What do territory owners defend against?

“…This was confirmed by subsequent studies that included amongst others the effects of territory retention [9,58,59], settlement sequence [52,60,61], mortality [41,58] or population dynamics [10]. [29,33,41,53]). …”

“…what each party can expect to gain or lose depending on the outcome [29,32,33] or physical properties of the contested resource, such as-in the case of food-size, handling time or predictability of occurrence (e.g. [34,35]).…”

“…For a full picture, however, it will be necessary to integrate habitat and species properties (e.g. [110,111]), cognitive mechanisms [112], interaction mechanics [33,113], population feedback [66] and resource properties [35,94].…”

Optimal aggression in kleptoparasitic interactions

“…Here we modify a game-theoretical "producer-scrounger" model developed in Broom et al (2014a). Producer-scrounger models (Barnard and Sibly, 1981;Barnard, 1984;Vickery et al, 1991;Caraco and Giraldea, 1991;Dubois and Giraldeau, 2005b) describe interactions where, after a kleptoparasite (i.e.…”

“…Many game-theoretical models of two-individual interactions have been developed wherein the individuals have a discrete set of strategies available to them (Smith and Price, 1973;Dubois and Giraldeau, 2005a;, but realistically individuals competing in kleptoparasitic interactions can invest amounts of energy from a continuous range of possibilities. This possibility is incorporated in the model from Broom et al (2014a) and also in our model. In Broom et al (2014a), the producer-scrounger conflict is modeled as an extensive form game where the scrounger chooses its strategy first and the producer knows the scrounger's choice before making its own.…”