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More than meets the eye : Predator-induced pupil size plasticity in a teleost fish

Vinterstare, Jerker LU ; Hulthén, Kaj LU ; Nilsson, Dan E. LU ; Nilsson, Per Anders LU and Brönmark, Christer LU (2020) In Journal of Animal Ecology 89(10). p.2258-2267
Abstract

Most animals are visually oriented, and their eyes provide their ‘window to the world’. Eye size correlates positively with visual performance, because larger eyes can house larger pupils that increase photon catch and contrast discrimination, particularly under dim light, which have positive effects on behaviours that enhance fitness, including predator avoidance and foraging. Recent studies have linked predation risk to selection for larger eyes and pupils, and such changes should be of importance for the majority of teleost fishes as they have a pupil that is fixed in size (eyes lack a pupillary sphincter muscle) and, hence, do not respond to changes in light conditions. Here, we quantify eye and pupil size of individual crucian... (More)

Most animals are visually oriented, and their eyes provide their ‘window to the world’. Eye size correlates positively with visual performance, because larger eyes can house larger pupils that increase photon catch and contrast discrimination, particularly under dim light, which have positive effects on behaviours that enhance fitness, including predator avoidance and foraging. Recent studies have linked predation risk to selection for larger eyes and pupils, and such changes should be of importance for the majority of teleost fishes as they have a pupil that is fixed in size (eyes lack a pupillary sphincter muscle) and, hence, do not respond to changes in light conditions. Here, we quantify eye and pupil size of individual crucian carp, a common freshwater fish, following controlled manipulations of perceived predation risk (presence/absence). We also tested if crucian carp responded to increased predation risk by shifts in diel activity patterns. We found that crucian carp show phenotypic plasticity with regards to pupil size, but not eye size, as pupil size increased when exposed to predators (pike). Predator-exposed crucian carp also shifted from diurnal to nocturnal activity. Using a modelling exercise, we moreover show that the plastically enlarged pupils significantly increase visual range, especially for small objects under dim light conditions. Overall, our results provide compelling evidence for predator-induced pupil enlargement resulting in enhanced visual capabilities in a teleost fish. Pupil size plasticity in combination with the observed shift towards nocturnal activity may allow for efficient foraging also under dark conditions when predation risk from diurnal and visually oriented predators is reduced. The data highlight the powerful role of predation risk for eye development and evolution.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
crucian carp, eye evolution, inducible defence, phenotypic plasticity, predator–prey interactions, pupil size, vision, visual ecology
in
Journal of Animal Ecology
volume
89
issue
10
pages
10 pages
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • pmid:33460050
  • scopus:85089447058
ISSN
0021-8790
DOI
10.1111/1365-2656.13303
language
English
LU publication?
yes
id
0c5a2098-eb65-49b9-834a-62e6808fb42a
date added to LUP
2020-08-25 09:04:01
date last changed
2021-02-24 03:00:02
@article{0c5a2098-eb65-49b9-834a-62e6808fb42a,
  abstract     = {<p>Most animals are visually oriented, and their eyes provide their ‘window to the world’. Eye size correlates positively with visual performance, because larger eyes can house larger pupils that increase photon catch and contrast discrimination, particularly under dim light, which have positive effects on behaviours that enhance fitness, including predator avoidance and foraging. Recent studies have linked predation risk to selection for larger eyes and pupils, and such changes should be of importance for the majority of teleost fishes as they have a pupil that is fixed in size (eyes lack a pupillary sphincter muscle) and, hence, do not respond to changes in light conditions. Here, we quantify eye and pupil size of individual crucian carp, a common freshwater fish, following controlled manipulations of perceived predation risk (presence/absence). We also tested if crucian carp responded to increased predation risk by shifts in diel activity patterns. We found that crucian carp show phenotypic plasticity with regards to pupil size, but not eye size, as pupil size increased when exposed to predators (pike). Predator-exposed crucian carp also shifted from diurnal to nocturnal activity. Using a modelling exercise, we moreover show that the plastically enlarged pupils significantly increase visual range, especially for small objects under dim light conditions. Overall, our results provide compelling evidence for predator-induced pupil enlargement resulting in enhanced visual capabilities in a teleost fish. Pupil size plasticity in combination with the observed shift towards nocturnal activity may allow for efficient foraging also under dark conditions when predation risk from diurnal and visually oriented predators is reduced. The data highlight the powerful role of predation risk for eye development and evolution.</p>},
  author       = {Vinterstare, Jerker and Hulthén, Kaj and Nilsson, Dan E. and Nilsson, Per Anders and Brönmark, Christer},
  issn         = {0021-8790},
  language     = {eng},
  number       = {10},
  pages        = {2258--2267},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Journal of Animal Ecology},
  title        = {More than meets the eye : Predator-induced pupil size plasticity in a teleost fish},
  url          = {http://dx.doi.org/10.1111/1365-2656.13303},
  doi          = {10.1111/1365-2656.13303},
  volume       = {89},
  year         = {2020},
}