Macquarie University
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Lateralisation and sociability under natural and experimental predation pressure in the Trinidadian guppy (Poecilia reticulata)

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posted on 2023-11-08, 04:10 authored by Iestyn Lloyd Penry-Williams

Predators impose a strong selective pressure on the behavioural traits of prey species. Group living, or sociability, allows individuals to reduce their own risk of predation through avoidance, dilution, and confusion effects. Another potentially beneficial mechanism is behavioural lateralisation, or “handedness”, the asymmetrical expression of cognitive brain functions through a directional bias in visual or motor tasks. In my thesis, I explore the interaction between behavioural lateralisation, sociability, and predation in both natural and captive populations of Trinidadian guppies (Poecilia reticulata). In Chapter Two, I examine the consistency between current behavioural lateralisation methodologies and assess the assumptions behind these methods, including the number of incorporated turn choices and the impact of random chance. In Chapter Three, I present the use of environmental DNA in assessing natural piscine guppy predator communities at six sites across the Northern Range of Trinidad. Using this measure of predation, I assess its viability in predicting differentiation of adaptive anti-predatory behaviours in natural guppies, including sociability, activity, and both visual and motor lateralisation. In Chapter Four, I assess the visual lateralisation of guppies tested either solitarily or in groups in the presence or absence of a live predator, the blue acara (Andinoacara pulcher). Using a repeated measures design, I investigate the repeatability of guppies’ visual lateralisation in terms of personality variation across the investigated contexts. In Chapter Five, I assess the visual lateralisation of natural guppies when viewing a social stimulus and their sociability across a gradient of predation risk using nineteen sites in the Northern Range of Trinidad. Overall, my research demonstrates relatively low levels of lateralisation throughout contexts and populations. However, subtle trends in the lateralisation of eye-use when viewing a predatory or social stimulus appear to exist in relation to predation risk, with an apparent social conformity in lateralisation when assessed in groups. 


NERC (Natural Environment Research Council) GW4 + Doctoral Training Programme

Macquarie University Cotutelle (NE/L002434/1)


Table of Contents

1 Chapter one: general introduction -- 2 Chapter two: the consistency of lateralisation indexes across prominent assays for assessing lateralisation in fish -- 3 Chapter three: the use of environmental DNA in predicting behavioural differentiation in wild, native Trinidadian guppies under variable predation regimes -- 4 Chapter four: the impact and interaction of predation risk and group association on visual lateralisation in predator inspections -- 5 Chapter five: the impact of predation risk and sociability on visual lateralisation of a social stimulus in wild, native Trinidadian guppies under variable predation regimes -- 6 Chapter six: general conclusions -- 7 Appendix -- 8 Bibliography

Awarding Institution

Macquarie University. University of Bristol

Degree Type

Thesis PhD


Doctor of Philosophy

Department, Centre or School

Department of Biological Sciences

Year of Award


Principal Supervisor

Christos Ioannou

Additional Supervisor 1

Culum Brown

Additional Supervisor 2

Martin Genner


Copyright: The Author Copyright disclaimer:




273 pages

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