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Daily activity rhythms, chronotypes, and risk-taking behavior in the signal crayfish

Sbragaglia, Valerio; Breithaupt, Thomas


Valerio Sbragaglia

Thomas Breithaupt


Claudio Carere


Consistent inter-individual differences in daily activity rhythms (i.e., chronotypes) can have ecological consequences in determining access to food resources and avoidance of predators. The most common measure to characterize chronotypes in animals as well as humans is the onset of activity (i.e., early or late chronotypes). However, daily activity rhythms may also differ in the relative amount of activity displayed at particular time periods. Moreover, chronotypes may also be linked to other consistent inter-individual differences in behavior (i.e., personality), such as the propensity to take risks. Here, we used the signal crayfish Pacifastacus leniusculus to test the presence of chronotypes and risk-taking personality traits and a potential behavioral syndrome between these traits. We first exposed crayfish to 5 days of light–darkness to measure daily activity rhythms and then we applied a visual predator-simulating stimulus in 2 different contexts (neutral and food). Our results showed consistent (i.e., across 5 days) inter-individual differences in the relative nocturnal activity displayed in the early and middle, but not in the late part of darkness hours. Moreover, while crayfish displayed inter-individual differences in risk-taking behavior, these were not found to be consistent across 2 contexts. Therefore, we were not able to formally test a behavioral syndrome between these 2 traits. In conclusion, our study provides the first evidence of chronotypes in the relative amount of activity displayed at particular time periods. This could be a valuable information for applied ecological aspects related to the signal crayfish, which is a major invasive species of freshwater ecosystems.


Sbragaglia, V., & Breithaupt, T. (2022). Daily activity rhythms, chronotypes, and risk-taking behavior in the signal crayfish. Current Zoology, 68(2), 177-184.

Journal Article Type Article
Acceptance Date Mar 7, 2021
Online Publication Date Mar 12, 2021
Publication Date Apr 1, 2022
Deposit Date Apr 14, 2021
Publicly Available Date Apr 15, 2021
Journal Current Zoology
Print ISSN 1674-5507
Electronic ISSN 2396-9814
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 68
Issue 2
Article Number zoab023
Pages 177-184
Keywords Behavioral syndrome; Biological rhythms; Boldness; Feeding; Locomotor activity
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Copyright Statement
©The Author(s) (2021). Published by Oxford University Press on behalf of Editorial Office, Current Zoology. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (,
which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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