Test‐dependent expression of behavioral syndromes: A study of aggressiveness, activity, and stress of chub

Abstract

Aggressiveness has been one of the behavioral traits most examined with various standard testing methods. We used two distinct methods (the mirror and the real opponent tests) to evaluate individual aggression and relate it to the activity and individual stress of chub (Squalius cephalus L.). Three hypotheses were formulated and tested: (a) there is a significant positive relationship between the aggressiveness of individuals measured with the mirror and the real opponent tests, indicating their convergent validity; (b) the irregularities in response to the aggressiveness and activity tests lead to the context‐specific expression of the behavioral syndromes; and (c) there is a significant positive relationship between the stress induced in individuals by both tests of aggressiveness, demonstrating individually consistent stress‐coping strategies. The first and the second hypothesis were confirmed, while the third hypothesis was rejected. Our results suggest that particular tests of aggressiveness could act as a situation with high strength, leaving little variation between individual responses. Thus, we propose that for the proper interpretation of various studies using different tests to study identical behavioral traits, it is important to consider the convergent validity of not only the tested behavioral traits but also the individual stress responses. The chub also showed stress relieve through aggressiveness, suggesting the species as a prospective animal model to the study interaction between the stress and the aggressiveness. A detailed aggression ethogram of chub was provided to facilitate the use of this specie in future studies.

Stressful Daylight: Differences in Diel Rhythmicity Between Albino and Pigmented Fish

“…Over 160,000 raw data points were obtained during the artificial stream experiment. The "locomotor activity" of each fish was calculated as the number of artificial stream units passed within the 1-min time grid according to the activity measures of juvenile chub (Horký et al, 2014;Hubená et al, 2020) or catfish (Slavík et al, 2016a). All the values were subsequently grouped into four equidistantly distributed sampling intervals (two during the day and two during night) with the mean individual locomotor activity values.…”

Pupil size variation as a response to stress in European catfish and its application for social stress detection in albino conspecifics

“…For example, compared to pigmented conspecifics, albinos are less active and aggressive [12][13][14] and albinos are socially ostracized [15], which can explain why they are presented as losers in competition for resources [16]. Hence, for detecting the stress-induced status of an albino individual accompanying its social interactions, it is not possible to use the methods based on variability in pigmentation and/or eye darkening reported for salmons [17], tropical cichlids and cyprinids [18][19][20][21]. Presumably, stress in albinos can be alternatively detected by pupil size variation (PSV).…”