Individual differences in activity levels in zebrafish (Danio rerio)

Abstract

Individual differences and variation in behavioural responses have been identified in many animal species. These differences may be the result of genetic or environmental factors or the interaction between them. Analysis of individual differences in behaviour may be important for many reasons. The zebrafish is a powerful model organism that is rapidly gaining popularity in behavioural brain research. However, individual differences have rarely been explored in zebrafish although significant variation in their performance has been reported. In the current study we identified individual differences in activity levels of zebrafish using a genetically heterogeneous population. Groups of zebrafish classified as high, medium, or low activity performers demonstrated consistent activity levels over a period of 7 days, and also in a subsequent open field task, suggesting stable individual differences as opposed to stochastic variation among subjects. We also uncovered a sex dependent relationship between behavioural measures. Female zebrafish in the high activity group preferred the top portion of the tank, whereas low activity females preferred the lower portion but males did not show such a relationship. The relationship between these two behaviours in females implies the potential existence of a behavioural syndrome persisting between contexts. Furthermore, females demonstrated a higher level of consistency in their behaviour as compared to males, and the behavioural differences were found to be independent of both body size and weight of the tested subjects. The identification of individual differences in activity levels in zebrafish will allow the investigation of underlying genetic and/or environmental underpinnings.

Differential effects of dopamine D1 and D2/3 receptor antagonism on motor responses

“…Distance from bottom is used as a measure of anxiety, with fish swimming near the top being regarded as less anxious (Tran and Gerlai 2013b;Pannia et al 2014;Levin et al 2007). SCH-23390 is an agonist for serotonin (5HT) 1C and 2C receptors at higher concentrations (Millan et al 2001;Briggs et al 1991) and may alter anxiety-like responses in zebrafish through activation of the serotoninergic system.…”

Animal Personality Relates to Thermal Preference in Wild-Type Zebrafish,Danio rerio

“…1 Proactive individuals are typically bolder, more aggressive, and risk takers, tending to follow behavioral routines than their reactive counterparts and with different activity patterns in wild 8 and captive populations. 9 This set of characteristics has led to the suggestion that these individuals may be more successful under stable and predictable environmental conditions. 10 On the other hand, the reactive behavioral phenotype displays a more flexible behavior, as they do not usually establish routines.…”

Acute exposure to 17α-ethinylestradiol alters boldness behavioral syndrome in female Siamese fighting fish

“…Levels of aggression and boldness are related in males (Hebert et al, 2014) and the stronger syndrome in males than females may be a byproduct of artificial selection for aggression in males. Sex differences in behavioral syndromes have recently been found in zebrafish where females have higher activity levels and respond more consistently than males (Tran and Gerlai, 2013). Behavior in exposed females looked quite different from the behavior of unexposed individuals.…”

“…Given the occurrence of a behavioral syndrome in male Siamese fighting fish and the ubiquity of a boldness behavioral syndrome in fishes (Sih et al, 2004), we predicted that a similar behavioral syndrome for boldness across contexts would be present in adult females. Alternatively, sex differences in the degree of boldness or strength of the behavioral syndrome could occur like in guppies, round gobies, and zebrafish (Harris et al, 2010;Marentette et al, 2011;Tran and Gerlai, 2013). In terms of the effects of EE2 exposure on female behavior, we were uncertain as to whether or not females would be affected.…”