Mortality risk of spatial positions in animal groups: The danger of being in the front

Dirk Bumann; Jens Krause; Daniel Ian Rubenstein

doi:10.1163/156853997X00403

Mortality risk of spatial positions in animal groups: The danger of being in the front

Dirk Bumann
, Jens Krause
, Daniel Ian Rubenstein

Research output: Contribution to journal › Article › peer-review

Original language	English (US)
Pages (from-to)	1063-1076
Number of pages	14
Journal	BEHAVIOUR
Volume	134
Issue number	13-14
DOIs	https://doi.org/10.1163/156853997X00403
State	Published - Nov 1997

All Science Journal Classification (ASJC) codes

Animal Science and Zoology
Behavioral Neuroscience

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10.1163/156853997X00403

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@article{b248f3e1f00447749e51345979c04efb,

title = "Mortality risk of spatial positions in animal groups: The danger of being in the front",

author = "Dirk Bumann and Jens Krause and Rubenstein, \{Daniel Ian\}",

note = "Funding Information: We modified Hamilton's (1971) selfish herd model by introducing directional movement to the prey groups and the predators. The consequences of this modification with regards to differential predation risks are compared to Hamilton's original model (using station- ary prey groups) and tested against empirical data. In model 1, we replicated Hamilton's original predator-prey system. In models 2 and 3, prey groups were mobile and predators were mobile (model 2) or stationary (model 3). Our results indicate that additional to the positive risk gradient from centre to periphery predicted by Hamilton's model for station-ary groups, there might be another positive risk gradient from the rear to the front part in moving groups. Furthermore, models 2 and 3 suggest that moving groups should generally exhibit an elongated shape (longer than wide along the axis of locomotion) if risk minimisation is the only factor concerned. Also smaller inter-individual distances are predicted for front individuals than individuals elsewhere in the group. Empirical data based on the three-dimensional structure of fish shoals (using roach, Rutilus rutilus) were consistent with the above two predictions. A second experiment which involved lake chub, Semotilus atromaculatus, as prey and rock bass, Ambloplites rupestris, as predators, provided direct support for the hypothesis that individuals in front positions of groups incurred a signifi- cantly higher predation risk than fish in rear positions. Finally, we discuss the differential 5) Corresponding author: J. Krause, Department of Biology, University of Leeds, LS2 9JT, UK; e-mail: [email protected] 6) We are grateful to Dietmar Todt for providing us with facilities for the experimental part of this project and to Philip Muruthi and the members of the Ecology and Evolution Group of the Biology Department in Leeds for stimulating discussions. Helpful comments were also provided by William Hamilton and one anonymous referee. JK was supported by a BASF grant of the Studienstiftung des deutschen Volkes.",

year = "1997",

month = nov,

doi = "10.1163/156853997X00403",

language = "English (US)",

volume = "134",

pages = "1063--1076",

journal = "BEHAVIOUR",

issn = "0005-7959",

publisher = "Brill Academic Publishers",

number = "13-14",

}

TY - JOUR

T1 - Mortality risk of spatial positions in animal groups

T2 - The danger of being in the front

AU - Bumann, Dirk

AU - Krause, Jens

AU - Rubenstein, Daniel Ian

N1 - Funding Information: We modified Hamilton's (1971) selfish herd model by introducing directional movement to the prey groups and the predators. The consequences of this modification with regards to differential predation risks are compared to Hamilton's original model (using station- ary prey groups) and tested against empirical data. In model 1, we replicated Hamilton's original predator-prey system. In models 2 and 3, prey groups were mobile and predators were mobile (model 2) or stationary (model 3). Our results indicate that additional to the positive risk gradient from centre to periphery predicted by Hamilton's model for station-ary groups, there might be another positive risk gradient from the rear to the front part in moving groups. Furthermore, models 2 and 3 suggest that moving groups should generally exhibit an elongated shape (longer than wide along the axis of locomotion) if risk minimisation is the only factor concerned. Also smaller inter-individual distances are predicted for front individuals than individuals elsewhere in the group. Empirical data based on the three-dimensional structure of fish shoals (using roach, Rutilus rutilus) were consistent with the above two predictions. A second experiment which involved lake chub, Semotilus atromaculatus, as prey and rock bass, Ambloplites rupestris, as predators, provided direct support for the hypothesis that individuals in front positions of groups incurred a signifi- cantly higher predation risk than fish in rear positions. Finally, we discuss the differential 5) Corresponding author: J. Krause, Department of Biology, University of Leeds, LS2 9JT, UK; e-mail: [email protected] 6) We are grateful to Dietmar Todt for providing us with facilities for the experimental part of this project and to Philip Muruthi and the members of the Ecology and Evolution Group of the Biology Department in Leeds for stimulating discussions. Helpful comments were also provided by William Hamilton and one anonymous referee. JK was supported by a BASF grant of the Studienstiftung des deutschen Volkes.

PY - 1997/11

Y1 - 1997/11

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UR - https://www.scopus.com/pages/publications/0001724259#tab=citedBy

U2 - 10.1163/156853997X00403

DO - 10.1163/156853997X00403

M3 - Article

AN - SCOPUS:0001724259

SN - 0005-7959

VL - 134

SP - 1063

EP - 1076

JO - BEHAVIOUR

JF - BEHAVIOUR

IS - 13-14

ER -

Mortality risk of spatial positions in animal groups: The danger of being in the front

All Science Journal Classification (ASJC) codes

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