Long‐term repeatability of behaviours in zebrafish (Danio rerio)

• Published in: Ethology 2020-08, Vol.126 (8), p.803-811
• Main Authors: Thomson, Hilary R., Lamb, Simon D., Besson, Anne A., Johnson, Sheri L., Wright, Jonathan
• Format: Article
• Language: English
• Subjects: activity; Animal behavior; animal personality; anxiety; Behavior; Danio rerio; exploration; Exploratory behavior; Gender aspects; novel arena; Personality; Phenotyping; Reproducibility; Sex differences; Zebrafish
• ISSN: 0179-1613; 1439-0310
• DOI: 10.1111/eth.13038

Animal personality is defined as individual variation in behaviour that is consistent over time and/or across contexts. Animal personality is now considered a fundamental aspect in the fields of animal behaviour and behavioural ecology, yet the majority of studies assess repeatability of behaviours over only relatively short time periods (e.g. a week) using just two measures. Understanding whether behavioural traits are repeatable over longer periods is important for the assessment of individual differences in behaviour. Using zebrafish (Danio rerio), we investigated the repeatability of activity and exploratory behaviours, including distance travelled, time spent in the bottom of the arena, stationary time and overall exploration of the novel arena over a 28‐week period, using five intervals. All measures were repeatable over 28 weeks, but the repeatability estimates were much lower when comparing the initial week one and week two behaviours. There were clear sex differences in aspects of activity, with males more active than females. Importantly, our behavioural assays suggest that zebrafish require an initial “tank experience,” prior to the main phenotyping session, to ensure that behaviours being measured are repeatable—these effects are often not considered, but have implications for the many studies that measure behaviour at a single time point only. Mean (± standard error) total distance moved (a), time spent in the bottom of the tank (b), time spent stationary (c) and exploration (d) across 28 weeks of testing (assayed at 1‐, 2‐, 6‐, 15‐ and 28‐week time points) for male (open circle) and female (filled circle) AB wild‐type zebrafish. Weeks correspond to 29, 30, 35, 42 and 55 weeks of age post‐fertilisation.