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Experimental manipulation of perceived predation risk and cortisol generates contrasting trait trajectories in plastic crucian carp

Vinterstare, Jerker LU ; Hulthén, Kaj LU ; Nilsson, P. Anders LU ; Nilsson Sköld, Helen and Brönmark, Christer LU (2020) In The Journal of experimental biology 223.
Abstract

Most animals constitute potential prey and must respond appropriately to predator-mediated stress in order to survive. Numerous prey also adaptively tailor their response to the prevailing level of risk and stress imposed by their natural enemies, i.e. they adopt an inducible defence strategy. Predator exposure may activate the stress axis, and drive the expression of anti-predator traits that facilitate survival in a high-risk environment (the predation-stress hypothesis). Here, we quantified two key morphological anti-predator traits, body morphology and coloration, in crucian carp reared in the presence or absence of a predator (pike) in addition to experimental manipulation of physiological stress via implants containing either... (More)

Most animals constitute potential prey and must respond appropriately to predator-mediated stress in order to survive. Numerous prey also adaptively tailor their response to the prevailing level of risk and stress imposed by their natural enemies, i.e. they adopt an inducible defence strategy. Predator exposure may activate the stress axis, and drive the expression of anti-predator traits that facilitate survival in a high-risk environment (the predation-stress hypothesis). Here, we quantified two key morphological anti-predator traits, body morphology and coloration, in crucian carp reared in the presence or absence of a predator (pike) in addition to experimental manipulation of physiological stress via implants containing either cortisol or a cortisol inhibitor. We found that predator-exposed fish expressed a deeper-bodied phenotype and darker body coloration as compared with non-exposed individuals. Skin analyses revealed that an increase in the amount of melanophores caused the dramatic colour change in predator-exposed fish. Increased melanization is costly, and the darker body coloration may act as an inducible defence against predation, via a conspicuous signal of the morphological defence or by crypsis towards dark environments and a nocturnal lifestyle. By contrast, the phenotype of individuals carrying cortisol implants did not mirror the phenotype of predator-exposed fish but instead exhibited opposite trajectories of trait change: a shallow-bodied morphology with a lighter body coloration as compared with sham-treated fish. The cortisol inhibitor did not influence the phenotype of fish i.e. neither body depth nor body coloration differed between this group and predator-exposed fish with a sham implant. However, our results illuminate a potential link between stress physiology and morphological defence expression.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Colour change, Inducible defences, Phenotypic plasticity, Stress, Stress axis
in
The Journal of experimental biology
volume
223
article number
jeb213611
publisher
The Company of Biologists Ltd
external identifiers
  • scopus:85080841119
  • pmid:31974218
ISSN
1477-9145
DOI
10.1242/jeb.213611
language
English
LU publication?
yes
id
5a2ce64a-3679-448f-8cf3-55e24a619665
date added to LUP
2020-03-18 16:21:17
date last changed
2021-04-16 11:25:21
@article{5a2ce64a-3679-448f-8cf3-55e24a619665,
  abstract     = {<p>Most animals constitute potential prey and must respond appropriately to predator-mediated stress in order to survive. Numerous prey also adaptively tailor their response to the prevailing level of risk and stress imposed by their natural enemies, i.e. they adopt an inducible defence strategy. Predator exposure may activate the stress axis, and drive the expression of anti-predator traits that facilitate survival in a high-risk environment (the predation-stress hypothesis). Here, we quantified two key morphological anti-predator traits, body morphology and coloration, in crucian carp reared in the presence or absence of a predator (pike) in addition to experimental manipulation of physiological stress via implants containing either cortisol or a cortisol inhibitor. We found that predator-exposed fish expressed a deeper-bodied phenotype and darker body coloration as compared with non-exposed individuals. Skin analyses revealed that an increase in the amount of melanophores caused the dramatic colour change in predator-exposed fish. Increased melanization is costly, and the darker body coloration may act as an inducible defence against predation, via a conspicuous signal of the morphological defence or by crypsis towards dark environments and a nocturnal lifestyle. By contrast, the phenotype of individuals carrying cortisol implants did not mirror the phenotype of predator-exposed fish but instead exhibited opposite trajectories of trait change: a shallow-bodied morphology with a lighter body coloration as compared with sham-treated fish. The cortisol inhibitor did not influence the phenotype of fish i.e. neither body depth nor body coloration differed between this group and predator-exposed fish with a sham implant. However, our results illuminate a potential link between stress physiology and morphological defence expression.</p>},
  author       = {Vinterstare, Jerker and Hulthén, Kaj and Nilsson, P. Anders and Nilsson Sköld, Helen and Brönmark, Christer},
  issn         = {1477-9145},
  language     = {eng},
  month        = {02},
  publisher    = {The Company of Biologists Ltd},
  series       = {The Journal of experimental biology},
  title        = {Experimental manipulation of perceived predation risk and cortisol generates contrasting trait trajectories in plastic crucian carp},
  url          = {http://dx.doi.org/10.1242/jeb.213611},
  doi          = {10.1242/jeb.213611},
  volume       = {223},
  year         = {2020},
}