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Temporal clumping of prey and coexistence of unequal interferers: experiments on social forager groups of brown trout feeding on invertebrate drift

Author:
  • Mikael Jönsson
  • Christian Skov
  • Anders Koed
  • Anders Nilsson
Publishing year: 2008
Language: English
Pages: 1782-1787
Publication/Series: Oikos
Volume: 117
Issue: 12
Document type: Journal article
Publisher: Wiley-Blackwell

Abstract english

Environmental fluctuations have been proposed to enhance the coexistence of competing phenotypes. Evaluations are here presented on the effects of prey density and short-term temporal clumping of prey availability on the relative foraging success of unequal interferers in social forager groups of juvenile brown trout Salmo trutta feeding on drifting invertebrate prey (frozen chironomids). Groups of three trout with established linear dominance hierarchies (dominant, intermediate and subordinate) were subjected to three different total numbers of prey, combined with three different levels of temporal clumping of prey arrival, resulting in nine treatment combinations. Higher total number of prey increased the consumption for all dominance ranks, while higher temporal clumping decreased the consumption for the dominant individuals and increased the consumption for the subordinate individuals. The proportion of prey eaten was smaller at high prey numbers. Similarly, there was a trend that increased temporal clumping also decreased the proportion of prey eaten. We conclude that density and temporal clumping of prey contribute to the coexistence of unequal interferers, and that there is a potential positive feedback between prey behaviour and phenotypic coexistence through decreased per capita predation risk for prey that drift synchronously in high densities.

Keywords

  • Ecology

Other

Published
  • ISSN: 1600-0706
Anders Nilsson
E-mail: anders [dot] nilsson [at] biol [dot] lu [dot] se

Professor

Aquatic ecology

+46 46 222 83 65

+46 70 346 25 66

E-D130

50

Research group

Aquatic Ecology

Projects

Doctoral students and postdocs

Main supervisor

Varpu Pärssinen

Assistant supervisor

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