ZebrafishDanio rerioshows behavioural cross‐context consistency at larval and juvenile stages but no consistency between stages

Abstract

Coping style is defined as a set of individual physiological and behavioural characteristics that are consistent across time and context. In the zebrafish Danio rerio, as well as in many other animals, several covariations have been established among behavioural, physiological and molecular responses. Nonetheless, not many studies have addressed the consistency in behavioural responses over time starting at the larval stage. Therefore, this study aimed to improve the understanding of behavioural consistency across contexts and over time in zebrafish from the larval to juvenile stages. Two distinct experiments were conducted: a larval stage experiment (from 8 to 21 days post fertilization, dpf) and a juvenile stage experiment (from 21 to 60 dpf). On one hand, the larval experiment allows to focus on the transition between 8 and 21 dpf, marked by significant morphological changes related to the end of larval stage and initiation of metamorphosis. On the other hand, the juvenile experiment allows to properly cover the period extending from the end of larval stage to the juvenile stage (60 dpf), including metamorphosis which is itself completed around 45 dpf. Within each experiment, boldness was determined using a group risk-taking test to identify bold and shy individuals. A novel environment test was then performed at the same age to evaluate consistency across contexts. Groups of fish (either bold or shy) were bathed in an alizarin red S solution for later identification of their initially determined coping style to evaluate behavioural consistency over time. Fish were then reared under common garden conditions and challenged again with the same behavioural tests at a later age (21 and 60 dpf in the larval and juvenile experiments, respectively). Behavioural consistency was observed across contexts, with bold fish being more active and expressing higher thigmotaxis regardless of age. There was, however, little behavioural consistency over age, suggesting behavioural plasticity during development. Moreover, the use of alizarin red S to conduct this experiment provides new perspectives for the further study of the longitudinal evolution of various traits, including behaviour, over life stages in fish.

Size-selective mortality fosters ontogenetic changes in collective risk-taking behaviour in zebrafish, Danio rerio

“…We tested 60 groups (10 from each replicate line, 20 per treatment) or 480 fish in total. We conducted the assay every week from 8 to 22 days post fertilization or dpf (larval stages), at 45 dpf (juvenile), 61 and 85 dpf (subadult stages), and then every three weeks till 148 dpf and after six weeks at 190 dpf (adult stages) (Alfonso et al 2020 ). Behavioural changes in laboratory reared zebrafish is associated with morphological and physiological changes during larval (8–21 dpf), juvenile (21–60 dpf including metamorphosis around 45 dpf), subadult (60–90 dpf) and adult (90–190 dpf) stages (Alfonso et al 2020 ; Stednitz and Washbourne 2020 ).…”

“…We conducted the assay every week from 8 to 22 days post fertilization or dpf (larval stages), at 45 dpf (juvenile), 61 and 85 dpf (subadult stages), and then every three weeks till 148 dpf and after six weeks at 190 dpf (adult stages) (Alfonso et al 2020 ). Behavioural changes in laboratory reared zebrafish is associated with morphological and physiological changes during larval (8–21 dpf), juvenile (21–60 dpf including metamorphosis around 45 dpf), subadult (60–90 dpf) and adult (90–190 dpf) stages (Alfonso et al 2020 ; Stednitz and Washbourne 2020 ). Though the maturation schedules of our size-selected lines are different with both the large-harvested and small-harvested line maturing earlier at smaller sizes than the controls (Uusi‐Heikkilä et al 2015 ), we tested them at the abovementioned stages to have an uniform experimental timeline (Fig.…”

Transcriptomic profiles of consistent risk-taking behaviour across time and contexts in European sea bass

“…Mean latency to exit the covered side of the GRT tank greatly varied over time, indicating that environment and/or age impact risk-taking behaviour. Although we are unable to identify causes of this variation, it supports that risk-taking behaviour is relatively plastic and can be affected by biotic or abiotic changes [25,40]. Nevertheless, within our studied population, individuals showed heterogeneous risk-taking behaviour which was moderately consistent over time and environmental conditions.…”

“…We observed moderate consistency in the latency to leave the initial area over a relatively long period of time (ICC = 0.38), and for whether fish left the initial area at all (ICC = 0.35). Previous studies have also demonstrated consistency in fish behaviour overtime within a population [15,40,47,48], but only few exceeded 45 days [26,47,49]. Long-term consistency in personality traits have, nevertheless, been studied in multiple mammal species.…”

Fish Personality: Meta-Theoretical Issues, Personality Dimensions, and Applications to Neuroscience and Psychopathology

“…The ontogenesis of the exploration-avoidance dimension has been more thoroughly investigated than boldness. Using emergence tests, some authors observed within-population differences in exploration-avoidance at very early stages of development (Alfonso et al, 2020;Edenbrow & Croft, 2011;Ibarra-Zatarain et al, 2020;Polverino et al, 2016), while other investigated its consistency along ontogeny (Alfonso et al, 2020;Castanheira et al, 2013;Edenbrow & Croft, 2011;Polverino et al, 2016). Fernandes-Silva et al (2022) observed that zebrafish separated by the time of egg hatching ("early hatchers" vs.…”