Information transfer between foraging animals: The consequences of attentional limitations

Fraser, Christopher P (2005) Information transfer between foraging animals: The consequences of attentional limitations. PhD thesis, University of Glasgow.

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Abstract

Since its inception during the 1960's, optimal foraging theory has become a popular and well-studied field in behavioural ecology. A vast expanse of empirical work has been carried out to investigate whether animals forage optimally, and how they achieve this. Researchers have also used a range of theoretical techniques to predict the behaviour of animals foraging under various ecological conditions. Particular attention has been paid to animals feeding in isolated and depleting food patches, and the length of time they should be willing to spend feeding in such patches before quitting to move to the next (patch residence time, or PRT) in order to maximise long-term prey capture rates. The modelling work presented in this thesis examines further, various aspects of optimal foraging theory, investigating PRT and the longterm foraging success of group foragers.A contentious theory attracting much research, is that individuals foraging in groups which share information regarding the successful capture of food resources may be better off than when not sharing such information, or when foraging alone. This use of public information (PI) allows them to acquire information relating to the quality of a food patch more quickly. At any one time they will have better knowledge of the decreasing patch quality, and be able to make a more accurate estimate of when to quit and move to another patch. I demonstrate that animals sharing such information do indeed experience benefits over groups that do not share public information, but not over lone foragers. This suggests that although PI itself is not likely to promote the formation of animal groups, in an environment where animals have already formed cohesive groups (for example where predation risk is high) sharing PI offers a further advantage to them. This model, and others before it are based upon a formula which calculates an estimate of the number of prey remaining in a food patch, depending upon the distribution of prey resources throughout the environment, the length of time spent by foragers in a food patch, and the number of prey discovered there. When foraging in groups, this model assumes that each forager keeps a track of the total number of prey caught in a patch by inferring its own foraging success on to each other forager in the group. As group size increases this is likely to be more and more unrealistic, because although prey is likely to be discovered more quickly, each forager faces a lower chance of finding any. I present an alternative model that removes this bias in large groups. I demonstrate that using this new estimator, foragers are generally better able to estimate patch quality when in large groups, but their ability to do so is more variable from patch to patch. The work in this thesis offers insights into several aspects of social foraging theory, with particular emphasis on public information sharing. With the models presented here, I make predictions that can be tested empirically to give us a deeper understanding into why animals share public information, the benefits and obstacles they face by doing so, and the obstacles they must overcome when feeding in groups. These models provide a framework that can in the future be adapted to make predictions for specific ecological systems, but can also be combined or modified further for a more complete investigation into the behavioural ecology of social foraging under cognitive constraints. (Abstract shortened by ProQuest.).

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: Graeme Ruxton
Keywords: Ecology, Behavioral sciences
Date of Award: 2005
Depositing User: Enlighten Team
Unique ID: glathesis:2005-74234
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 23 Sep 2019 15:33
Last Modified: 23 Sep 2019 15:33
URI: http://theses.gla.ac.uk/id/eprint/74234

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