Intraspecific resource partitioning in brown trout: the temporal distribution of foraging is determined by social rank

Alanara, A., Burns, M.D. and Metcalfe, N.B. (2001) Intraspecific resource partitioning in brown trout: the temporal distribution of foraging is determined by social rank. Journal of Animal Ecology, 70(6), pp. 980-986. (doi:10.1046/j.0021-8790.2001.00550.x)

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Publisher's URL: http://dx.doi.org/10.1046/j.0021-8790.2001.00550.x

Abstract

Animals can reduce the competition for a limiting resource by temporal segregation, whereby individuals exploit the resource at different times. However, the pay-offs may vary predictably over time, and it can be predicted that (a) more dominant competitors should gain access to resources at the preferred times and (b) the degree of temporal segregation will vary with the intensity of competition. Here we show experimentally that individual brown trout Salmo trutta (L.) made sequential use of foraging areas, with dominant individuals feeding mainly at the most beneficial times of dusk and the early part of the night while more subordinate fish fed at other times. However, the degree of overlap in foraging times between high-ranking fish was dependent on energetic demands. At low temperatures (when requirements were low) the temporal activity patterns of top-ranking fish were synchronized, with foraging concentrated at the preferred times. In contrast, when temperature was raised to increase energetic requirements, activity patterns showed strong temporal segregation: the most dominant fish remained predominantly nocturnal, whereas second-ranking fish became increasingly diurnal. This is the first experimental demonstration of shifts in the daily pattern of activity caused by varying intensity of intraspecific competition.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Metcalfe, Professor Neil
Authors: Alanara, A., Burns, M.D., and Metcalfe, N.B.
Subjects:Q Science > QH Natural history > QH301 Biology
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Journal of Animal Ecology
ISSN:0021-8790
ISSN (Online):1365-2656
Published Online:26 March 2002

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