scholarly journals Familiarity and shoal cohesion in fathead minnows (Pimephales promelas): implications for antipredator behaviour

1995 ◽  
Vol 73 (5) ◽  
pp. 955-960 ◽  
Author(s):  
Douglas P. Chivers ◽  
Grant E. Brown ◽  
R. Jan F. Smith

We exposed groups of four fathead minnows (Pimephales promelas) that were familiar to each other and had been taken from naturally occurring shoals, and groups of four fish unfamiliar to each other, taken from four separate shoals, to either chemical stimuli from pike or a model fish predator (northern pike, Esox lucius). In response to both chemical stimuli from pike and the pike model, minnows from familiar groups showed greater shoal cohesion than those from unfamiliar groups. Tighter shoal cohesion should result in a higher probability of surviving an encounter with a predator. Fish in familiar shoals also exhibited more dashing, a known antipredator response, than those in unfamiliar groups. In addition, groups of familiar fish showed less freezing behaviour than unfamiliar groups. In response to the model fish predator, familiar shoals exhibited a greater number of predator inspections, and the number of inspectors per inspection visit was greater, than those in unfamiliar groups. These results suggest that preferential shoaling with familiar conspecifics leads to an increase in cooperative antipredator behaviour and may thereby lower a minnow's risk of predation.

Behaviour ◽  
2002 ◽  
Vol 139 (9) ◽  
pp. 1099-1109 ◽  
Author(s):  
Reehan Mirza ◽  
Douglas Chivers

AbstractSeveral species of aquatic organisms release chemical cues upon detecting predators. These chemicals may serve to 'warn' nearby conspecifics of the predator and hence have been termed disturbance cues. Disturbance cues are thought to be low-level indicators of risk to which prey animals respond with antipredator behaviour. However, little is known about the distribution of disturbance cues among different taxa or how prey animals use these cues to mediate their risk of predation. In this study we exposed brook charr (Salvelinus fontinalis) to water from a tank containing cues of disturbed or undisturbed conspecifics at the same time as we exposed them to cues of an unknown predator, northern pike (Esox lucius). In subsequent trials, we staged encounters between the charr and a pike and tested for differences in survival. We found that charr that were exposed to simultaneous cues from disturbed conspecifics and pike odour subsequently avoided the pike significantly more than charr that had been previously exposed to chemical stimuli from undisturbed charr plus pike odour. Moreover, pike took significantly longer to capture charr that had been previously exposed to disturbance cues from conspecifics plus pike stimuli compared to charr previously exposed to cues from undisturbed charr plus pike stimuli. Ours is the first study to demonstrate that detection of disturbance cues can provide a survival benefit during an encounter with a predator.


2001 ◽  
Vol 79 (12) ◽  
pp. 2239-2245 ◽  
Author(s):  
Grant E Brown ◽  
James C Adrian, Jr. ◽  
Todd Patton ◽  
Douglas P Chivers

Hypoxanthine-3-N-oxide (H3NO) has been identified as the putative alarm pheromone of ostariophysan fishes. Previously we demonstrated a population-specific minimum behavioural-response threshold in fathead minnows (Pimephales promelas) to a H3NO concentration of approximately 0.4 nM. Minnows may, however, perceive low concentrations of H3NO as a predation threat, even though they do not exhibit an overt behavioural response. We conducted a series of laboratory trials to test the hypothesis that minnows can detect the alarm pheromone at concentrations below the minimum behavioural-response threshold. We exposed predator-naïve fathead minnows to H3NO at concentrations ranging from 0.4 to 0.05 nM paired with the odour of a novel predator (yellow perch, Perca flavescens) or distilled water paired with perch odour. We observed significant increases in antipredator behaviour (increased shoal cohesion, movement towards the substrate, a reduction in feeding, and an increase in the occurrence of dashing and freezing behaviour) in shoals of minnows exposed to a combined cue of 0.4 nM H3NO and perch odour (compared with a distilled-water control), but not by shoals exposed to lower concentrations of H3NO paired with perch odour or those exposed to distilled water paired with perch odour. When exposed to perch odour alone 4 days later, minnows initially conditioned to H3NO at concentrations of 0.4–0.1 nM exhibited significant increases in antipredator behaviour. These data demonstrate that minnows attend to the alarm pheromone at concentrations below the minimum behavioural-response threshold and are able to acquire the ability to recognize a novel predator even though they do not exhibit an overt behavioural response.


1995 ◽  
Vol 73 (12) ◽  
pp. 2209-2215 ◽  
Author(s):  
Mark V. Abrahams

Prey species have two fundamental strategies for reducing their probability of being killed by a predator: behavioural modification and morphological defenses. It is hypothesized that prey species which possess morphological defenses should exhibit less behavioural modification in response to predation risk than species lacking such defenses. Experiments were conducted to examine behavioural modification by armoured (brook sticklebacks, Culea inconstans) and unarmoured (fathead minnows, Pimephales promelas) prey species foraging in the presence of a predator (yellow perch, Perca flavescens). Two experiments measured habitat avoidance and reactive distance to an approaching predator. The results of these experiments were consistent with the hypothesis. Compared with fathead minnows, brook sticklebacks exhibited relatively little behavioural modification in response to the presence of a predator, both in terms of avoiding dangerous areas and in their reactive distance to an approaching predator. Sticklebacks, however, graded their reactive distance to an approaching predator in relation to both their body size and group size. These data suggest that the morphology of brook sticklebacks and their behavioural sensitivity to predation risk may allow them to efficiently exploit habitats that contain predators.


1992 ◽  
Vol 70 (8) ◽  
pp. 1473-1476 ◽  
Author(s):  
Alicia Mathis ◽  
R. Jan F. Smith

If chemical alarm pheromones warn individuals of nearby predation on conspecifics, then individuals should avoid areas where alarm pheromone is present. This hypothesis was tested in a natural stream habitat by exposing fathead minnows (Pimephales promelas) to minnow traps that had been marked with either conspecific alarm pheromone or with a control substance (glass-distilled water). The minnows exhibited significant avoidance of traps marked with the alarm pheromone: less than 4% of the minnows that were captured were found in the experimental traps. There was a nonsignificant tendency for minnows in control traps to be larger than those caught in experimental traps, suggesting a possible role of experience or developmental factors in determining the response to alarm pheromone. There was no apparent difference in overall body condition (i.e., length-specific mass) between the minnows that were caught in control versus experimental traps. Detection of the alarm pheromone may allow receivers to avoid areas where risk of predation is high.


Behaviour ◽  
2002 ◽  
Vol 139 (7) ◽  
pp. 929-938 ◽  
Author(s):  
Douglas Chivers ◽  
Reehan Mirza ◽  
Jeffery Johnston

AbstractNumerous species of aquatic animals release chemical cues when attacked by a predator. These chemicals serve to warn other conspecifics, and in some cases heterospecifics, of danger, and hence have been termed alarm cues. Responses of animals to alarm cues produced by other species often need to be learned, yet mechanisms of learned recognition of heterospecific cues are not well understood. In this study, we tested whether fathead minnows (Pimephales promelas) could learn to recognize a heterospecific alarm cue when it was combined with conspecific alarm cue in the diet of a predator. We exposed fathead minnows to chemical stimuli collected from rainbow trout, Oncorhynchus mykiss, fed a mixed diet of minnows and brook stickleback, Culaea inconstans, or trout fed a mixed diet of swordtails, Xiphophorous helleri, and stickleback. To test if the minnows had acquired recognition of the heterospecific alarm cues, we exposed them to stickleback alarm cues and introduced an unknown predator, yellow perch (Perca flavescens) or northern pike (Esox lucius). Both perch and pike took longer to initiate an attack on minnows that were previously exposed to trout fed minnows and stickleback than those previously exposed to trout fed swordtails and stickleback. These results demonstrate that minnows can learn to recognize heterospecific alarm cues based on detecting the heterospecific cue in combination with minnow alarm cues in the diet of the predator. Ours is the first study to demonstrate that behavioural responses to heterospecific chemical alarm cues decreases the probability that the prey will be attacked and captured during an encounter with a predator.


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