Stress responses to conspecific visual cues of predation risk in zebrafish.

Thiago Acosta Oliveira,Darlan Gusso,João Gabriel Dos Santos Rosa,Rodrigo Egydio Barreto,Leonardo José Gil Barcellos,Renan Idalencio,Murilo Sander De Abreu,Fabiana Kalichak,Gessi Koakoski,Ana Cristina Varrone Giacomini,Denis Brook Rosemberg

doi:10.7717/peerj.3739

Abstract

Chemical communication relating to predation risk is a trait common among fish species. Prey fish under threat of predation can signal risk to conspecific fish, which then exhibit defensive responses. Fish also assess predation risk by visual cues and change their behavior accordingly. Here, we explored whether these behavioral changes act as visual alarm signals to conspecific fish that are not initially under risk. We show that shoals of zebrafish (Danio rerio) visually exposed to a predator display antipredator behaviors. In addition, these defensive maneuvers trigger antipredator reactions in conspecifics and, concomitantly, stimulate the hypothalamus-pituitary-interrenal axis, leading to cortisol increase. Thus, we conclude that zebrafish defensive behaviors act as visual alarm cues that induce antipredator and stress response in conspecific fish.

Highlights

Prey–predator interactions occur throughout the animal kingdom (Cresswell, 2010), with every interaction involving both unique and general characteristics
We found that visual perception of the predator increased whole-body cortisol in both SF and RF zebrafish compared to the SF control (P = 0.0077 (Fig. 2A); SF comparison P = 0.0006, K = 14.92 (Fig. 2B); RF comparison P = 0.001, K = 13.74 (Fig. 2C))
The type of stimulus fish had a significant effect on defensive behavior (P < 0.0001; F2,18 = 96.09); both SF and RF fish exposed to a predator fish spent more in the bottom section of the tank, whereas SF and RF fish exposed to a non-predator fish spent more time in the bottom section but this response was less intense than those SF and RF observed in predator exposure treatment, considering the comparison of both groups with the control group (Fig. 2D)

Summary

Introduction

Prey–predator interactions occur throughout the animal kingdom (Cresswell, 2010), with every interaction involving both unique and general characteristics. There is a vast amount of information in the scientific literature about these types of perceptions in fish (Wisendem, Vollbrechet & Brown, 2004; Barcellos et al, 2011) in response to the presence of a predator, and in conspecific fish threatened by a predator (Jordão & Volpato, 2000). Different combinations of these signals in the presence of a predator, or even the diverse forms of communication about a predator threat, between conspecific prey induce different antipredator maneuvers (O’Connor et al, 2015).

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Results

Conclusion