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Effects of group size on the threat-sensitive response to varying concentrations of chemical alarm cues by juvenile convict cichlids

Title:

Effects of group size on the threat-sensitive response to varying concentrations of chemical alarm cues by juvenile convict cichlids

Brown, Grant E. and Bongiorno, Tony and DiCapua, Daniel M. and Ivan, Laura I. and Roh, Ellie (2006) Effects of group size on the threat-sensitive response to varying concentrations of chemical alarm cues by juvenile convict cichlids. Canadian Journal of Zoology, 84 (1). pp. 1-8. ISSN 0008-4301

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Official URL: http://dx.doi.org/10.1139/Z05-166

Abstract

The threat-sensitive predator avoidance model predicts that prey should balance the intensity of antipredator responses against perceived predation risk, resulting in a graded response pattern. Recent studies have demonstrated considerable interspecific variation in the intensity of threat-sensitive response patterns, ranging from strongly graded to relatively nongraded or "hypersensitive" threat-sensitive response patterns. Here, we test for intraspecific plasticity in threat-sensitive responses by varying group size. We exposed juvenile convict cichlids, Archocentrus nigrofasciatus (Günther, 1867), as individuals or in small (groups of three) or large (groups of six) shoals to a series of dilutions of conspecific chemical alarm cues and a distilled water control. Singleton cichlids exhibited significant reductions in time spent moving and in frequency of foraging attempts (relative to distilled water controls) when exposed to a 12.5% dilution of conspecific alarm cue, with no difference in response intensity at higher stimulus concentrations, suggesting a nongraded (hypersensitive) response pattern. Small shoals exhibited a similar response pattern, but at a higher response threshold (25% dilution of stock alarm cue solution). Large shoals, however, exhibited a graded response pattern. These results suggest that group size influences the trade-off between predator avoidance and other fitness related activities, resulting in flexible threat-sensitive response patterns.

Divisions:Concordia University > Faculty of Arts and Science > Biology
Item Type:Article
Refereed:Yes
Authors:Brown, Grant E. and Bongiorno, Tony and DiCapua, Daniel M. and Ivan, Laura I. and Roh, Ellie
Journal or Publication:Canadian Journal of Zoology
Date:January 2006
Funders:
  • Concordia
  • Natural Sciences and Engineering Research Council
ID Code:6725
Deposited By:DANIELLE DENNIE
Deposited On:18 Jun 2010 13:23
Last Modified:08 Dec 2010 18:15
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