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Defence on Demand : A physiological perspective on phenotypic plasticity in anti-predator traits

Vinterstare, Jerker LU (2021)
Abstract
Almost all species face some degree of predation risk, and, hence, evolution has produced a plethora of anti-predator defences. However, anti-predator strategies require resources, and the prevailing risk of becoming prey is influenced by many factors and rarely constant across time and space. Evolution has therefore favoured the development of phenotypic plasticity in anti-predator defences. The capacity of a single genotype to fine-tune its phenotype according to the prevailing risk of predation results in a closer phenotype-environment match in the mercurial environments of the natural world. Interest in the ecology and evolution of inducible defences has progressed the development of its theoretical underpinnings, along with empirical... (More)
Almost all species face some degree of predation risk, and, hence, evolution has produced a plethora of anti-predator defences. However, anti-predator strategies require resources, and the prevailing risk of becoming prey is influenced by many factors and rarely constant across time and space. Evolution has therefore favoured the development of phenotypic plasticity in anti-predator defences. The capacity of a single genotype to fine-tune its phenotype according to the prevailing risk of predation results in a closer phenotype-environment match in the mercurial environments of the natural world. Interest in the ecology and evolution of inducible defences has progressed the development of its theoretical underpinnings, along with empirical tests of theoretical predictions. Inter-individual differences in the expression of inducible traits are nowadays understood ubiquitous, and this intriguing variation holds possibility to bridge our current knowledge gap on the proximate, physiological mechanisms underlying inducible morphological defence regulation.

In this thesis, I address unanswered questions on the proximate, physiological processes behind phenotypic plasticity in morphological defences. I first examine classic resource-allocation trade-offs to search for hidden physiological costs coupled with perceived predation risk and investment into a morphological defence. I further employ a recent hypothesis of physiological stress being the mechanism driving morphological defence regulation. To test my predictions, I have used a well-established model system for the study of inducible morphological defences, the crucian carp (Carassius carassius).

I show that innate immune functions are altered by predator exposure, and that the defence against pathogens is correlated with the morphological defence against larger-sized enemies (predators). Second, from a series of laboratory experiments and field studies, I demonstrate support for the hypothesis of stress physiology being involved in plastic defence expression, and that crucian carp display clear sexual dimorphism in the anti-predator phenotype. I suggest that this is due to sex-specific trade-off dynamics, where females invest more into reproduction, resulting in less resources for anti-predator protection. Finally, I present novel trait changes (changes in body colour, diel activity and eye morphology) in response to non-lethal predation risk that may act in synergy to produce an integrated anti-predator phenotype.

In summary, my results illustrate a potential causality from the vertebrate stress axis to the regulation of morphological defence expression. Further, my thesis highlights variation and complexity on the route to producing optimal anti-predator phenotypes under competing demands from other interests.
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Abstract (Swedish)
Almost all species face some degree of predation risk, and, hence, evolution has produced a plethora of anti-predator defences. However, anti-predator strategies require resources, and the prevailing risk of becoming prey is influenced by many factors and rarely constant across time and space. Evolution has therefore favoured the development of phenotypic plasticity in anti-predator defences. The capacity of a single genotype to fine-tune its phenotype according to the prevailing risk of predation results in a closer phenotype-environment match in the mercurial environments of the natural world. Interest in the ecology and evolution of inducible defences has progressed the development of its theoretical underpinnings, along with empirical... (More)
Almost all species face some degree of predation risk, and, hence, evolution has produced a plethora of anti-predator defences. However, anti-predator strategies require resources, and the prevailing risk of becoming prey is influenced by many factors and rarely constant across time and space. Evolution has therefore favoured the development of phenotypic plasticity in anti-predator defences. The capacity of a single genotype to fine-tune its phenotype according to the prevailing risk of predation results in a closer phenotype-environment match in the mercurial environments of the natural world. Interest in the ecology and evolution of inducible defences has progressed the development of its theoretical underpinnings, along with empirical tests of theoretical predictions. Inter-individual differences in the expression of inducible traits are nowadays understood ubiquitous, and this intriguing variation holds possibility to bridge our current knowledge gap on the proximate, physiological mechanisms underlying inducible morphological defence regulation.

In this thesis, I address unanswered questions on the proximate, physiological processes behind phenotypic plasticity in morphological defences. I first examine classic resource-allocation trade-offs to search for hidden physiological costs coupled with perceived predation risk and investment into a morphological defence. I further employ a recent hypothesis of physiological stress being the mechanism driving morphological defence regulation. To test my predictions, I have used a well-established model system for the study of inducible morphological defences, the crucian carp (Carassius carassius).

I show that innate immune functions are altered by predator exposure, and that the defence against pathogens is correlated with the morphological defence against larger-sized enemies (predators). Second, from a series of laboratory experiments and field studies, I demonstrate support for the hypothesis of stress physiology being involved in plastic defence expression, and that crucian carp display clear sexual dimorphism in the anti-predator phenotype. I suggest that this is due to sex-specific trade-off dynamics, where females invest more into reproduction, resulting in less resources for anti-predator protection. Finally, I present novel trait changes (changes in body colour, diel activity and eye morphology) in response to non-lethal predation risk that may act in synergy to produce an integrated anti-predator phenotype.

In summary, my results illustrate a potential causality from the vertebrate stress axis to the regulation of morphological defence expression. Further, my thesis highlights variation and complexity on the route to producing optimal anti-predator phenotypes under competing demands from other interests.
(Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Metcalfe, Neil, University of Glasgow, UK
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Phenotypic plasticity, inducible defences, stress physiology, cortisol, immune function, trade-offs, sexual dimorphism, crucian carp, visual ecology, predator-prey interactions, POMC (pro-opiomelanocortin), colour change, eco-immunology, Anti-predator defences, Inducible morphological defence, Phenotypic plasticity, Stress physiology, Cortisol, Immune function, Crucian carp, Predator-prey interactions, Trade-offs, Sexual dimorphism, POMC, Pro-opiomelanocortin, Visual ecology, Eye evolution, Melanin, Eco-immunology, Pace-of-life, Behavioural plasticity
pages
202 pages
publisher
Lund University
defense location
Blå Hallen, Ekologihuset, Sölvegatan 37, Lund Join via zoom: https://lu-se.zoom.us/j/63027208479
defense date
2021-03-19 13:00:00
ISBN
978-91-7895-756-9
978-91-7895-755-2
language
English
LU publication?
yes
id
8a93a761-d44c-48fb-9bcc-5d20bf460666
date added to LUP
2021-02-11 14:56:03
date last changed
2021-02-23 08:39:25
@phdthesis{8a93a761-d44c-48fb-9bcc-5d20bf460666,
  abstract     = {Almost all species face some degree of predation risk, and, hence, evolution has produced a plethora of anti-predator defences. However, anti-predator strategies require resources, and the prevailing risk of becoming prey is influenced by many factors and rarely constant across time and space. Evolution has therefore favoured the development of phenotypic plasticity in anti-predator defences. The capacity of a single genotype to fine-tune its phenotype according to the prevailing risk of predation results in a closer phenotype-environment match in the mercurial environments of the natural world. Interest in the ecology and evolution of inducible defences has progressed the development of its theoretical underpinnings, along with empirical tests of theoretical predictions. Inter-individual differences in the expression of inducible traits are nowadays understood ubiquitous, and this intriguing variation holds possibility to bridge our current knowledge gap on the proximate, physiological mechanisms underlying inducible morphological defence regulation. <br/><br/>In this thesis, I address unanswered questions on the proximate, physiological processes behind phenotypic plasticity in morphological defences. I first examine classic resource-allocation trade-offs to search for hidden physiological costs coupled with perceived predation risk and investment into a morphological defence. I further employ a recent hypothesis of physiological stress being the mechanism driving morphological defence regulation. To test my predictions, I have used a well-established model system for the study of inducible morphological defences, the crucian carp (Carassius carassius). <br/><br/>I show that innate immune functions are altered by predator exposure, and that the defence against pathogens is correlated with the morphological defence against larger-sized enemies (predators). Second, from a series of laboratory experiments and field studies, I demonstrate support for the hypothesis of stress physiology being involved in plastic defence expression, and that crucian carp display clear sexual dimorphism in the anti-predator phenotype. I suggest that this is due to sex-specific trade-off dynamics, where females invest more into reproduction, resulting in less resources for anti-predator protection. Finally, I present novel trait changes (changes in body colour, diel activity and eye morphology) in response to non-lethal predation risk that may act in synergy to produce an integrated anti-predator phenotype. <br/><br/>In summary, my results illustrate a potential causality from the vertebrate stress axis to the regulation of morphological defence expression. Further, my thesis highlights variation and complexity on the route to producing optimal anti-predator phenotypes under competing demands from other interests. <br/>},
  author       = {Vinterstare, Jerker},
  isbn         = {978-91-7895-756-9},
  language     = {eng},
  publisher    = {Lund University},
  school       = {Lund University},
  title        = {Defence on Demand : A physiological perspective on phenotypic plasticity in anti-predator traits},
  url          = {https://lup.lub.lu.se/search/ws/files/91129529/e_spik_ex_Jerker.pdf},
  year         = {2021},
}