Population, sex and body size: determinants of behavioural variations and behavioural correlations among wild zebrafish Danio rerio

Abstract

This study (1) investigated variation among populations and the effects of sex and body size on boldness, activity and shoal-association tendency among wild zebrafish, and (2) tested for existence of correlations between behaviours, controlling for sex and body size. Individuals across four natural populations were tested for general activity in a novel situation, number of predator inspections undertaken and tendency to associate with a conspecific shoal in the presence of predators. Results showed a significant effect of population on boldness with a population from high-predation habitat being bolder than populations from low-predation habitats. Males showed significantly higher tendencies than females to associate with a conspecific shoal in the presence of predators. Further, a negative relationship was found between activity and boldness only within two low-predation populations. Individual body size had a strong effect on the activity–boldness relationship within the low-predation population from flowing water habitat. Smaller fish were bolder and less active while larger fish were more cautious and active. Overall, the results indicated that while population-level behavioural responses might be shaped by predation pressure, state-dependent factors could determine behavioural correlations among individuals within populations.

Repeatability and reliability of exploratory behavior in proactive and reactive zebrafish, Danio rerio

“…Time spent in the center zone showed the greatest variability across weeks compared to stationary time and swimming speed. While several studies have found sex-specific behavioral variation of mating and aggressive behaviors 46,47,60 , we did not observe any sex differences in exploratory behavior.…”

“…The local ecological factors that might have contributed to shaping the WC animals’ behavior are not known. It is possible that some population differences or behavioral correlations may only emerge under certain local environmental conditions 16,46,65 . Several studies that investigated wild zebrafish populations found that predation and water flow can explain population differences in behavioral correlations between boldness, aggression and activity 16,46 .…”

“…It is possible that some population differences or behavioral correlations may only emerge under certain local environmental conditions 16,46,65 . Several studies that investigated wild zebrafish populations found that predation and water flow can explain population differences in behavioral correlations between boldness, aggression and activity 16,46 . While these studies examined between-population differences, similar patterns have been observed within populations across time in collared flycatcher birds ( Ficedula albicollis ).…”

“…Additionally, artificial selection of exploratory behavior will constrain morphological evolution and glucocorticoid responses 31,45 . While the consistency of exploratory behavior has not been extensively studied in individual strains of proactive and reactive zebrafish, several studies have suggested that other boldness, aggression, and locomotor behaviors are generally consistent across contexts and time, and are influenced by selective pressures 33,46–48 . Thus, zebrafish can provide unique insights into underlying mechanisms of behavioral variation in coping with stress and subsequently how variation can be constrained by selective forces acting on populations.…”

Differential effects of ethanol on behavior and GABAAreceptor subunit expression in zebrafish (Danio rerio) with alternative stress coping styles

“…Line (HSB, LSB), sex (male, female) and treatment group (0.75% ethanol, control) were used as between-subject variables. As the relationship between body size and locomotion is well documented 45,54–56 , we included standard length as a covariate. Since we did not find a significant main effect of sex on behavior (top transitions: χ 2 (1) = 2.385, p = 0.123; top time: χ 2 (1) = 0.852, p = 0.356; distance: χ 2 (1) = 0.682, p = 0.409; and stationary time: χ 2 (1) = 0.092, p = 0.762) or gene expression ( gabra1: χ 2 (1) =0.036, p = 0.850; gabra2: χ 2 (1) = 0.382, p = 0.536; gadrd: χ 2 (1) = 1.942, p = 0.163; gabrg2: χ 2 (1) = 1.426, p = 0.232), we removed that variable from the analyses and used a simpler GLZ with line and treatment group as the only between-subject variables.…”