Species integrity enhanced by a predation cost to hybrids in the wild

P. A. Nilsson, Kaj Hulthén, Ben B. Chapman, Lars-Anders Hansson, Jakob Brodersen, Henrik Baktoft, Jerker Vinterstare, Christer Brönmark, Christian Skov

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Abstract

Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of-concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3-4 years later identified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.
Original languageEnglish
Article number20170208
JournalBiology Letters
Volume13
Issue number7
Number of pages4
ISSN1744-9561
DOIs
Publication statusPublished - 2017

Bibliographical note

Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.

Keywords

  • cormorant
  • diversity
  • evolution
  • fish
  • predator–prey

Cite this

Nilsson, P. A., Hulthén, K., Chapman, B. B., Hansson, L-A., Brodersen, J., Baktoft, H., ... Skov, C. (2017). Species integrity enhanced by a predation cost to hybrids in the wild. Biology Letters, 13(7), [20170208]. https://doi.org/10.1098/rsbl.2017.0208
Nilsson, P. A. ; Hulthén, Kaj ; Chapman, Ben B. ; Hansson, Lars-Anders ; Brodersen, Jakob ; Baktoft, Henrik ; Vinterstare, Jerker ; Brönmark, Christer ; Skov, Christian. / Species integrity enhanced by a predation cost to hybrids in the wild. In: Biology Letters. 2017 ; Vol. 13, No. 7.
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Nilsson, PA, Hulthén, K, Chapman, BB, Hansson, L-A, Brodersen, J, Baktoft, H, Vinterstare, J, Brönmark, C & Skov, C 2017, 'Species integrity enhanced by a predation cost to hybrids in the wild', Biology Letters, vol. 13, no. 7, 20170208. https://doi.org/10.1098/rsbl.2017.0208

Species integrity enhanced by a predation cost to hybrids in the wild. / Nilsson, P. A.; Hulthén, Kaj; Chapman, Ben B.; Hansson, Lars-Anders; Brodersen, Jakob; Baktoft, Henrik; Vinterstare, Jerker; Brönmark, Christer; Skov, Christian.

In: Biology Letters, Vol. 13, No. 7, 20170208, 2017.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Species integrity enhanced by a predation cost to hybrids in the wild

AU - Nilsson, P. A.

AU - Hulthén, Kaj

AU - Chapman, Ben B.

AU - Hansson, Lars-Anders

AU - Brodersen, Jakob

AU - Baktoft, Henrik

AU - Vinterstare, Jerker

AU - Brönmark, Christer

AU - Skov, Christian

N1 - Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.

PY - 2017

Y1 - 2017

N2 - Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of-concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3-4 years later identified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.

AB - Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of-concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo). Scanning for regurgitated tags under cormorant roosts 3-4 years later identified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.

KW - cormorant

KW - diversity

KW - evolution

KW - fish

KW - predator–prey

U2 - 10.1098/rsbl.2017.0208

DO - 10.1098/rsbl.2017.0208

M3 - Journal article

C2 - 28747533

VL - 13

JO - Biology Letters

JF - Biology Letters

SN - 1744-9561

IS - 7

M1 - 20170208

ER -

Nilsson PA, Hulthén K, Chapman BB, Hansson L-A, Brodersen J, Baktoft H et al. Species integrity enhanced by a predation cost to hybrids in the wild. Biology Letters. 2017;13(7). 20170208. https://doi.org/10.1098/rsbl.2017.0208