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Author Earley, R.L.; Dugatkin, L.A.
Title Eavesdropping on visual cues in green swordtail (Xiphophorus helleri) fights: a case for networking Type Journal Article
Year 2002 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 269 Issue 1494 Pages 943-952
Keywords (down) *Aggression; Animals; *Behavior, Animal; *Cyprinodontiformes; Female; Male
Abstract Aggressive contests probably occur in networking environments where information about fighting ability is conveyed both to an opponent and to individuals peripheral to the fight itself, the bystanders. Our primary aim was to investigate the relative influences of eavesdropping and prior social experience on the dynamics of aggressive contests in Xiphophorus helleri. A bystander's ability to witness an encounter was manipulated using clear, one-way mirror, and opaque partitions. After watching (or not watching) the initial contest, the bystander encountered either the winner or loser of the bout. Treatment comparisons of bystander-winner or bystander-loser contest dynamics indicated the presence or absence of winner, loser, or eavesdropping effects. Winner and loser effects had negligible influences on bystander contest dynamics. Eavesdropping significantly reduced the bystander's propensity to initiate aggression, escalate, and win against seen winners regardless of whether the watched bout had escalated or not. Though eavesdropping had relatively little effect on bystander-loser contest dynamics, bystanders were less prone to initiate aggression and win against losers that had escalated in the witnessed bout. Thus, bystanders appear to preferentially retain and utilize information gained about potentially dangerous opponents (winners or persistent losers). Our data lend clear support for the importance of eavesdropping in visually based aggressive signalling systems.
Address Department of Biology, Life Science, Room 139, University of Louisville, Louisville, KY 40292, USA. rlearl01@athena.louisville.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:12028778 Approved no
Call Number refbase @ user @ Serial 498
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Author Johnstone, R.A.
Title Eavesdropping and animal conflict Type Journal Article
Year 2001 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 98 Issue 16 Pages 9177-9180
Keywords (down) *Aggression; Animals; *Behavior, Animal; *Conflict (Psychology); Models, Theoretical
Abstract Fights between pairs of animals frequently take place within a wider social context. The displays exchanged during conflict, and the outcome of an encounter, are often detectable by individuals who are not immediately involved. In at least some species, such bystanders are known to eavesdrop on contests between others, and to modify their behavior toward the contestants in response to the observed interaction. Here, I extend Maynard Smith's well known model of animal aggression, the Hawk-Dove game, to incorporate the possibility of eavesdroppers. I show that some eavesdropping is favored whenever the cost of losing an escalated fight exceeds the value of the contested resource, and that its equilibrium frequency is greatest when costs are relatively high. Eavesdropping reduces the risk of escalated conflict relative to that expected by chance, given the level of aggression in the population. However, it also promotes increased aggression, because it enhances the value of victory. The net result is that escalated conflicts are predicted to occur more frequently when eavesdropping is possible.
Address Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom. raj1003@hermes.cam.ac.uk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0027-8424 ISBN Medium
Area Expedition Conference
Notes PMID:11459936 Approved no
Call Number refbase @ user @ Serial 497
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Author Nicol, C.J.; Potzsch, C.; Lewis, K.; Green, L.E.
Title Matched concurrent case-control study of risk factors for feather pecking in hens on free-range commercial farms in the UK Type Journal Article
Year 2003 Publication British poultry science Abbreviated Journal Br Poult Sci
Volume 44 Issue 4 Pages 515-523
Keywords (down) *Aggression; Analysis of Variance; Animal Husbandry/methods; Animals; Case-Control Studies; Chickens/*physiology; Feathers; Female; Multivariate Analysis; Odds Ratio; Regression Analysis; Species Specificity
Abstract 1. The aim of the study was to compare the management and husbandry of free-range flocks in the UK where feather pecking was either present (case) or absent (control). 2. One hundred flocks were enrolled into a concurrent case-control study: 50 where birds had recently started feather pecking, and 50 matched control flocks where birds of the same age had not started feather pecking. 3. Information was obtained from a detailed interview with the flock manager, and by direct inspection of the flock, house and range. 4. Initial univariate analyses revealed that case flocks were more likely to comprise ISA Brown than Lohmann, were more likely to be restricted from litter areas to prevent floor eggs, and were less likely to use the outside range. 5. Cluster analysis indicated that feather pecking was not associated with any particular husbandry system. 6. The only influential risk factor significant in the multivariable conditional logistic regression analysis was use of the outdoor range. The risk of feather pecking was reduced 9-fold in flocks where more than 20% of birds used the range on sunny days (odds ratio = 0.12). Use of the range was positively associated with the presence of trees and/or hedges on the range.
Address Department of Clinical Veterinary Science, University of Bristol, England. c.j.nicol@bris.ac.uk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0007-1668 ISBN Medium
Area Expedition Conference
Notes PMID:14584840 Approved no
Call Number refbase @ user @ Serial 79
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