The Forager’s Dilemma: Food Sharing and Food Defense as Risk‐Sensitive Foraging Options

Département des Sciences Biologiques, Université du Québec à Montréal, Case postale 8888, Succursale Centre-Ville, Montréal, Québec H3C 3P8, Canada.
The American Naturalist (Impact Factor: 3.83). 01/2004; 162(6):768-79. DOI: 10.1086/379202
Source: PubMed


Although many variants of the hawk-dove game predict the frequency at which group foraging animals should compete aggressively, none of them can explain why a large number of group foraging animals share food clumps without any overt aggression. One reason for this shortcoming is that hawk-dove games typically consider only a single contest, while most group foraging situations involve opponents that interact repeatedly over discovered food clumps. The present iterated hawk-dove game predicts that in situations that are analogous to a prisoner's dilemma, animals should share the resources without aggression, provided that the number of simultaneously available food clumps is sufficiently large and the number of competitors is relatively small. However, given that the expected gain of an aggressive animal is more variable than the gain expected by nonaggressive individuals, the predicted effect of the number of food items in a clump-clump richness-depends on whether only the mean or both the mean and variability associated with payoffs are considered. More precisely, the deterministic game predicts that aggression should increase with clump richness, whereas the stochastic risk-sensitive game predicts that the frequency of encounters resulting in aggression should peak at intermediate clump richnesses or decrease with increasing clump richness if animals show sensitivity to the variance or coefficient of variation, respectively.

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Available from: Luc-Alain Giraldeau, Mar 12, 2014
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    • "A neuroeconomical approach may also facilitate translational approaches, as neuroeconomic paradigms can capture elements of social hierarchical organization, that is readily observable in animals, but traditionally harder to evaluate in humans. Indeed authors have used neuroeconomical paradigms in order to explain optimal foraging behavior in the wild (Dubois and Giraldeau, 2003). Although the amount of current scientific input from clinical populations is extremely limited, these recent suggestions are important in highlighting the potential of neuroeconomical paradigms as a cornerstone for the future of psychiatric research. "
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    Frontiers in Psychology 06/2013; 4:310. DOI:10.3389/fpsyg.2013.00310 · 2.80 Impact Factor
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    • "They may also adjust the intensity of their aggression depending on the value of the resource in dispute (Arnott and Elwood 2008); and fighting may occasionally escalate if information regarding contender asymmetry is imperfect (Maynard Smith and Parker 1976; Hongo 2003; Gherardi 2006). Dubois and Giraldeau (2003, 2007) suggested that if the finder is able to adjust its behavior to match that of its opponent, this should dissuade the joiner from escalating the fight and, when this happens, sharing the food might be the best strategy for both the finder and the joiner. Body size is frequently correlated with RHP and larger contestants tend to win in many species (Arnott and Elwood 2009). "
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    ABSTRACT: Theory predicts that asymmetry between contenders influences their ability to defend resources. More recently, some theoretical approaches have also examined the circumstances that might promote sharing of the disputed resources. We tested these hypotheses in males of the ball roller beetle Canthon cyanellus cyanellus. Males fight for possession of a food ball, which is a vital resource used for nesting. We evaluated the role of food resource ownership, body size and reproductive status on the outcome of contests (win, lose or share) between males that rolled a food ball (owners or finders) either alone or with a female partner, when faced with male intruders (or joiners). Large owners of a food ball had a higher probability of victory than small intruders, and small owners had a high probability of losing when faced with large intruders. The reproductive status of both contenders also influenced their chances of winning: previously mated owners of a food ball had a higher probability of winning than virgin owners. Males of a similar size tended to split the food ball, thereby sharing the resource. Our results suggest that competitors may adjust the intensity of their aggression depending at least on their own resource holding power (RHP), the value of the resource in dispute and perhaps even the RHP of their opponents. Sharing the food ball emerges as a fresh solution between similarly matched contestants. KeywordsAsymmetric contests– Canthon cyanellus cyanellus –Foraging competition–Resource holding power–Food sharing–Roller beetles
    Evolutionary Ecology 03/2011; 25(2):277-289. DOI:10.1007/s10682-010-9428-8 · 2.52 Impact Factor
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    • "Risk can play a role in social foraging decisions as food sharing can be an important method for overcoming risk (Dubois and Giraldeau 2003; Wu and Giraldeau 2005). We show that risk can play an important role in even the smallest of social groups, the pair, as risk partitioning can increase the fitness of both partners. "
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    Behavioral Ecology 08/2010; 21(5):1024-1032. DOI:10.1093/beheco/arq076 · 3.18 Impact Factor
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