DOI: 10.5061/dryad.4f4qrfjk2
title: Variation in personality shaped by evolutionary history, genotype, and developmental plasticity in response to feeding modalities in the Arctic charr

description: Animal personality has been shown to be influenced by both genetic and
 environmental factors and shaped by natural selection. Currently, little
 is known about mechanisms influencing the development of personality
 traits. This study examines the extent to which personality development is
 genetically influenced and/or environmentally responsive (plastic). We
 also investigated the role of evolutionary history, assessing whether
 personality traits could be canalized along a genetic and ecological
 divergence gradient. We tested the plastic potential of boldness in
 juveniles of five Icelandic Arctic charr morphs (Salvelinus alpinus),
 including two pairs of sympatric morphs, displaying various degrees of
 genetic and ecological divergence from the ancestral anadromous charr,
 split between treatments mimicking benthic vs. pelagic feeding modalities.
 We show that differences in mean boldness are mostly affected by genetics.
 While the benthic treatment led to bolder individuals overall, the
 environmental effect was rather weak, suggesting that boldness lies under
 strong genetic influence with reduced plastic potential. Finally, we found
 hints of differences by morphs in boldness canalization through reduced
 variance and plasticity, and higher consistency in boldness within morphs.
 These findings provide new insights into how behavioural development may
 impact adaptive diversification.
description: Research questions In the
 present study, we examined what roles genotype, plasticity and
 canalization play in the development of personality in the Arctic charr.
 We focused on a widely studied aspect of animal personality, boldness –
 the individual propensity to take risks – that has recently been reported
 in the Arctic charr. We hypothesized that:
 differences in ecological backgrounds lead
 to the evolution of different personality profiles between morphs
 (genotype). the early
 environment influences the developmental trajectories of personality
 traits (developmental plasticity of personality) within morphs.
 the degree of evolutionary divergence
 influences the degree of developmental plasticity of personality and the
 magnitude of personality range between morphs, potentially via
 canalization. To address this,
 juvenile full-sibs of AN, VS, VB, LB and PL Arctic charr morphs were
 reared in a common garden in benthic (feeding exclusively at the bottom)
 vs. pelagic (feeding exclusively in the water column) feeding modality
 treatments. We tested for differences in boldness repeatability, averages,
 and variances across morphs and treatments to characterize personality
 profiles. If personality development is under genetic
 influence (1.), we expected mean boldness to be morph-specific, or at
 least population-specific (between lakes/rivers). If
 personality development responds to environmental conditions,
 <em>i.e.</em>, is plastic (2.), we expected differences in
 mean boldness between treatments, either overall or within
 morphs. If a longer time since divergence leads to
 canalization of personality traits (3.), we expected reduced plasticity,
 lower boldness variance and higher boldness consistency (repeatability) in
 more diverged morphs. Note that these predictions are
 not mutually exclusive. Data acquisition
 All fish were submitted twice to a Open Field Test (OFT) with
 shelter, with a 7-day interval between each replication (video-recorded at
 30 frames per second). At the beginning of the test, the focal fish was
 placed in the closed shelter of the OFT arena. After 5 minutes of
 acclimation, the shelter door was opened and the fish was free to explore
 the arena for 20 minutes. The fish were tracked from the obtained videos
 with Ethovision XT version 14 (Noldus Information Technology). The arena
 was divided into four virtual zones: the shelter zone covering the shelter
 area, overlapping with an entry zone; the border zone along the edges of
 the arena; the centre zone being the remaining part of the arena⁠. The
 fish barycentre was used to calculate behavioural variables presented in
 the Metadata. Metadata 
 <strong>PCF</strong> = the unique ID of each
 individual fish 
 <strong>Trial.rep</strong> = the replication (either A or B)
 as OFT tests were repeated twice for each fish 
 <strong>Population</strong> = the morph (AN, VS, VB, LB, PL)
 to which the focal fish belongs 
 <strong>Trial.no</strong> = the number of the OFT trial,
 i.e. the order in which fish were tested. NB: one trial consisted of 4
 arenas tested simultaneously, hence 4 fish having the same
 trial.no <strong>Arena.no</strong> = the
 number of the arena in which the focal fish was tested during the
 trial <strong>Date</strong> = the day at
 which the OFT test took place for the focal fish 
 <strong>Time.categories</strong> = the time slot
 (Early.morning, Late.morning, Early.afternoon, etc) when the OFT test was
 carried out for the focal fish 
 <strong>Family</strong> = the family (crossing) to which the
 focal fish belongs. NB: there are 3 families per morph in our
 design. <strong>Color</strong> = the VIE
 color tag code identifying the focal fish 
 <strong>Size</strong> = the size category (Small, Medium,
 Large, corresponding respectively to the 1st, 2nd and 3rd quantiles of the
 body size distribution of a family within a tank) associated to each focal
 fish <strong>Tank</strong> = the tank
 replicate to which the focal fish belongs 
 <strong>Treatment</strong> = the feeding modality (Benthic or
 Pelagic) under which the focal fish was raised 
 <strong>T.before</strong> = temperature in the OFT arena at
 the beginning of the OFT trial (°C) 
 <strong>T.after</strong> = temperature in the OFT arena at the
 end of the OFT trial (°C) 
 <strong>T.average</strong> = the average temperature over the
 OFT trial, i.e., (T.before + T.after)/2 (°C)<br>NB: T.after
 measurements were not available (NA) for the first OFT trial (Trial.no:
 1). As the variation in temperature over the trials was usually very low
 (median increase of 0.6°C), we attributed a T.average value in each arena
 for this particular trial corresponding to the T.before value in each
 given arena. <strong>FL</strong> = fork
 length of the focal fish, measured from the tip of the snout to the fork
 of the caudal fin (cm) 
 <strong>TL</strong> = total length of the focal fish, measured
 from the tip of the snout to the tip of the caudal fin lobes
 (cm) <strong>m</strong> = weight of the
 fish (g) Behavioural variables recorded
 for the focal fish in the OFT arena during the 20-minute free
 phase: <strong>Dtot</strong> =
 the total distance travelled (cm) 
 <strong>v</strong> = the mean swimming velocity
 (cm/s) <strong>v.bl</strong> = the mean
 swimming velocity divided by the total length of the focal fish
 (<em>i.e.</em>, v/TL, s^-1) 
 <strong>v.ang</strong> = absolute angular velocity
 (deg/s) <strong>XXX.freq</strong> = the
 frequency of visits to the XXX zone 
 <strong>XXX.duration</strong> = the amount of time spent in
 the XXX zone (s) 
 <strong>Exit.time</strong> = the latency to exit the shelter
 for the first time (head and trunk visible, s)
description: # Variation in personality shaped by evolutionary history, genotype, and
 developmental plasticity in response to feeding modalities in the Arctic
 charr #### Marion
 Dellinger<sup style="font-size:13.5px;line-height:0;vertical-align:baseline;">1,2</sup>; Sarah E. Steele<sup style="font-size:13.5px;line-height:0;vertical-align:baseline;">2,3</sup>; Evert Sprockel<sup style="font-size:13.5px;line-height:0;vertical-align:baseline;">1,4</sup>; Joris Philip<sup style="font-size:13.5px;line-height:0;vertical-align:baseline;">1,5</sup>; Arnar Pálsson<sup style="font-size:13.5px;line-height:0;vertical-align:baseline;">2</sup>; David Benhaïm<sup style="font-size:13.5px;line-height:0;vertical-align:baseline;">1</sup> <sup style="font-size:10.5px;line-height:0;vertical-align:baseline;">1</sup> Department of Aquaculture and Fish Biology, Hólar University, Iceland; <sup style="font-size:10.5px;line-height:0;vertical-align:baseline;">2</sup> Institute of Life and Environmental Sciences, School of Engineering and Natural Sciences, University of Iceland, Iceland; <sup style="font-size:10.5px;line-height:0;vertical-align:baseline;">3</sup> Canadian Museum of Nature, Canada; <sup style="font-size:10.5px;line-height:0;vertical-align:baseline;">4</sup> HAS University, the Netherlands; <sup style="font-size:10.5px;line-height:0;vertical-align:baseline;">5</sup> Scottish Centre for Ecology and the Natural Environment, University of Glasgow, Scotland ## Research questions In the present study, we examined what roles genotype, plasticity and canalization play in the development of personality in the Arctic charr. We focused on a widely studied aspect of animal personality, boldness – the individual propensity to take risks – that has recently been reported in the Arctic charr. We hypothesised that: 1. differences in ecological backgrounds lead to the evolution of different personality profiles between morphs (genotype) 2. the early environment influences the developmental trajectories of personality traits (developmental plasticity of personality) within morphs 3. the degree of evolutionary divergence influences the degree of developmental plasticity of personality and the magnitude of personality range between morphs, potentially via canalization. To address this, juvenile full-sibs of AN, VS, VB, LB and PL Arctic charr morphs were reared in common garden in benthic vs. pelagic feeding modality treatments. We tested for differences in boldness repeatability, averages, and variances across morphs and treatments to characterise personality profiles. If personality development is under genetic influence (1.), we expected mean boldness to be morph-specific, or at least population-specific (between lakes/rivers). If personality development responds to environmental conditions, i.e., is plastic (2.), we expected differences in mean boldness between treatments, either overall or within morphs. If a longer time since divergence leads to canalization of personality traits (3.), we expected reduced plasticity, lower boldness variance and higher boldness consistency (repeatability) in more diverged morphs. Note that these predictions are not mutually exclusive. ## Data acquisition All fish were submitted twice to a Open Field Test (OFT) with shelter, with a 7-day interval between each replication (video-recorded at 30 frames per second). At the beginning of the test, the focal fish was placed in the closed shelter of the OFT arena. After 5 minutes acclimation, the shelter door was opened and the fish was free to explore the arena for 20 minutes. The fish were tracked from the obtained videos with Ethovision XT version 14 (Noldus Information Technology). The arena was divided into four virtual zones: the shelter zone covering the shelter area, overlapping with an entry zone; the border zone along the edges of the arena; the centre zone being the remaining part of the arena⁠. The fish barycentre was used to calculate behavioural variables presented in the Metadata. The associated dataset can be found under the name "RSPB-2023-2302_Data.xlsx". ## Metadata * **PCF** = the unique ID of each individual fish * **Trial.rep** = the replication (either A or B) as OFT tests were repeated twice for each fish * **Population** = the morph (AN, VS, VB, LB, PL) to which the focal fish belongs * **Trial.no** = the number of the OFT trial, i.e. the order in which fish were tested. NB: one trial consisted of 4 arenas tested simultaneously, hence 4 fish having the same trial.no * **Arena.no** = the number of the arena in which the focal fish was tested during the trial * **Date** = the day at which the OFT test took place for the focal fish * **Time.categories** = the time slot (Early.morning, Late.morning, Early.afternoon, etc) when the OFT test was carried out for the focal fish * **Family** = the family (crossing) to which the focal fish belongs. NB: there are 3 families per morph in our design. * **Color** = the VIE colour tag code identifying the focal fish * **Size** = the size category (Small, Medium, Large, corresponding respectively to the 1st, 2nd and 3rd quantiles of the body size distribution of a family within a tank) associated to each focal fish * **Tank** = the tank replicate to which the focal fish belongs * **Treatment** = the feeding modality (Benthic or Pelagic) under which the focal fish was raised * **T.before** = temperature in the OFT arena at the beginning of the OFT trial (°C) * **T.after** = temperature in the OFT arena at the end of the OFT trial (°C) * **T.average** = the average temperature over the OFT trial, i.e., (T.before + T.after)/2 (°C) NB: T.after measurements were not available (NA) for the first OFT trial (Trial.no: 1). As the variation in temperature over the trials was usually very low (median increase of 0.6°C), we attributed a T.average value in each arena for this particular trial corresponding to the T.before value in each given arena. * **FL** = fork length of the focal fish, measured from the tip of the snout to the fork of the caudal fin (cm) * **TL** = total length of the focal fish, measured from the tip of the snout to the tip of the caudal fin lobes (cm) * **m** = weight of the fish (g) Behavioural variables recorded for the focal fish in the OFT arena during the 20 minutes free phase: * **Dtot** = the total distance travelled (cm) * **v** = the mean swimming velocity (cm/s) * **v.bl** = the mean swimming velocity divided by the total length of the focal fish (i.e., v/TL, s^-1) * **v.ang** = absolute angular velocity (deg/s) * **XXX.freq** = the frequency of visits to the XXX zone * **XXX.duration** = the amount of time spent in the XXX zone (s) * **Exit.time** = the latency to exit the shelter for the first time (head and trunk visible, s) ## Code/Software/Supplements The code used to obtain boldness scores and analyse the data is available here under the name "RSPB-2023-2302_Accompanying_R_Script" both in .Rmd and in .html formats. Supplementary figures and tables associated to the main text can be found here under the name "RSPB-2023-2302_Supplements.pdf" as well as in the electronic supplementary material of the related article () through the following DOI: