scholarly journals Living in mixed species groups promotes predator learning in degraded habitats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Douglas P. Chivers ◽  
Mark I. McCormick ◽  
Eric P. Fakan ◽  
Randall P. Barry ◽  
Maud C. O. Ferrari
Keyword(s):  
Predation Risk ◽  
Abiotic Factors ◽  
Alarm Cues ◽  
Learning Mechanisms ◽  
Trade Offs ◽  
Chemical Alarm Cues ◽  
Pomacentrus Amboinensis ◽  
Predator Foraging ◽  
Predator Learning ◽  
Predator Odour

AbstractLiving in mix-species aggregations provides animals with substantive anti-predator, foraging and locomotory advantages while simultaneously exposing them to costs, including increased competition and pathogen exposure. Given each species possess unique morphology, competitive ability, parasite vulnerability and predator defences, we can surmise that each species in mixed groups will experience a unique set of trade-offs. In addition to this unique balance, each species must also contend with anthropogenic changes, a relatively new, and rapidly increasing phenomenon, that adds further complexity to any system. This complex balance of biotic and abiotic factors is on full display in the exceptionally diverse, yet anthropogenically degraded, Great Barrier Reef of Australia. One such example within this intricate ecosystem is the inability of some damselfish to utilize their own chemical alarm cues within degraded habitats, leaving them exposed to increased predation risk. These cues, which are released when the skin is damaged, warn nearby individuals of increased predation risk and act as a crucial associative learning tool. Normally, a single exposure of alarm cues paired with an unknown predator odour facilitates learning of that new odour as dangerous. Here, we show that Ambon damselfish, Pomacentrus amboinensis, a species with impaired alarm responses in degraded habitats, failed to learn a novel predator odour as risky when associated with chemical alarm cues. However, in the same degraded habitats, the same species learned to recognize a novel predator as risky when the predator odour was paired with alarm cues of the closely related, and co-occurring, whitetail damselfish, Pomacentrus chrysurus. The importance of this learning opportunity was underscored in a survival experiment which demonstrated that fish in degraded habitats trained with heterospecific alarm cues, had higher survival than those we tried to train with conspecific alarm cues. From these data, we conclude that redundancy in learning mechanisms among prey guild members may lead to increased stability in rapidly changing environments.

scholarly journals Disrupted learning: habitat degradation impairs crucial antipredator responses in naive prey

2016 ◽  
Vol 283 (1830) ◽  
pp. 20160441 ◽  
Author(s):  
Mark I. McCormick ◽  
Oona M. Lönnstedt
Keyword(s):  
Habitat Degradation ◽  
Coral Cover ◽  
Biodiversity Loss ◽  
Alarm Cues ◽  
Chemical Alarm Cues ◽  
Pomacentrus Amboinensis ◽  
Threat Cues ◽  
Habitat Generalist ◽  
Predator Learning ◽  
First Time

Habitat degradation is a global problem and one of the main causes of biodiversity loss. Though widespread, the mechanisms that underlie faunal changes are poorly understood. In tropical marine systems, corals play a crucial role in forming habitat, but coral cover on many reefs is declining sharply. Coral degradation affects the olfactory cues that provide reliable information on the presence and intensity of threat. Here, we show for the first time that the ability of a habitat generalist to learn predators using an efficient and widespread method of predator learning is compromised in degraded coral habitats. Results indicate that chemical alarm cues are no longer indicative of a local threat for the habitat generalist (the damselfish, Pomacentrus amboinensis ), and these cues can no longer be used to learn the identity of novel predators in degraded habitats. By contrast, a rubble specialist and congeneric ( Pomacentrus coelestis ) responded to olfactory threat cues regardless of background environment and could learn the identity of a novel predator using chemical alarm cues. Understanding how some species can cope with or acclimate to the detrimental impacts of habitat degradation on risk assessment abilities will be crucial to defining the scope of resilience in threatened communities.

Variable predation risk and the dynamic nature of mosquito antipredator responses to chemical alarm cues

Chemoecology ◽  
2007 ◽  
Vol 17 (4) ◽  
pp. 223-229 ◽  
Author(s):  
Maud C. O. Ferrari ◽  
François Messier ◽  
Douglas P. Chivers
Keyword(s):  
Predation Risk ◽  
Alarm Cues ◽  
Dynamic Nature ◽  
Chemical Alarm Cues ◽  
Antipredator Responses

Predator-recognition training of hatchery-reared walleye (Stizostedion vitreum) and a field test of a training method using yellow perch (Perca flavescens)

2004 ◽  
Vol 61 (11) ◽  
pp. 2144-2150 ◽  
Author(s):  
Brian D Wisenden ◽  
Josh Klitzke ◽  
Ryan Nelson ◽  
David Friedl ◽  
Peter C Jacobson
Keyword(s):  
Predation Risk ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Management Tool ◽  
Stizostedion Vitreum ◽  
Alarm Cues ◽  
Predation Mortality ◽  
Chemical Alarm Cues ◽  
In Captivity ◽  
Full Complement

Fishes reared in captivity are predator-naïve and suffer large predation mortality when stocked into lakes with a full complement of predators. We tested the potential of predator training to enhance post-stocking survival of hatchery-reared walleye (Stizostedion vitreum). In the first part of the study, we found that walleye (i) use chemical cues for assessing predation risk, (ii) do not have innate recognition of the odor of northern pike (Esox lucius) as an indicator of predation, and (iii) associate predation risk with pike odor after a single simultaneous encounter with pike odor and chemical alarm cues from walleye skin. In the second part of the study, we attempted to mass-train yellow perch, Perca flavescens (as a surrogate for walleye), to fear pike odor. Perch response to pike odor was not changed by placing sponge blocks containing pike odor and perch alarm cues around the perimeter of a pond. On pre- and post-training assays, perch avoided traps scented with perch alarm cues, but did not avoid traps labeled with pike odor or water. We conclude that recognition training offers potential as a management tool for walleye, but significant logistic challenges must be solved before it can be implemented.

scholarly journals Response of pumpkinseed sunfish to conspecific chemical alarm cues: an interaction between ontogeny and stimulus concentration

2003 ◽  
Vol 81 (10) ◽  
pp. 1671-1677 ◽  
Author(s):  
Jason P Marcus ◽  
Grant E Brown
Keyword(s):  
Standard Length ◽  
Relative Concentration ◽  
Lepomis Gibbosus ◽  
Skin Extract ◽  
Distilled Water ◽  
Alarm Cues ◽  
Pumpkinseed Sunfish ◽  
Trade Offs ◽  
Chemical Alarm Cues ◽  
Antipredator Responses

Recent studies have shown that juvenile centrachids undergo ontogenetic shifts in their behavioural response towards conspecific and heterospecific chemical alarm cues based on threat-sensitive trade-offs between the benefits associated with predator avoidance and foraging. We conducted laboratory studies to test the hypothesis that the relative concentration of conspecific alarm cues provides relevant information, allowing individuals to maximize these trade-offs. Juvenile (<40 mm standard length) and subadult (>95 mm standard length) pumpkinseed sunfish (Lepomis gibbosus) were exposed to conspecific skin extracts at stock (undiluted) concentration or diluted 1:1 (50%), 1:3 (25%), or 1:7 (12.5%) with distilled water. Juvenile sunfish exhibited significant antipredator responses (relative to the distilled water controls) when exposed to conspecific skin extracts at a concentration as low as 25%. Juveniles exposed to 12.5% skin extract were not significantly different from the distilled water controls. Subadult sunfish exhibited significant antipredator responses only to the two highest concentrations. In response to the two lowest concentrations (25% and 12.5%), however, subadult sunfish exhibited significant foraging responses. These data demonstrate that the relative concentration of chemical alarm cues provides reliable information and allows individuals to accurately assess local predation risk and hence maximize potential trade-offs.

Responses of American toad tadpoles to predation cues: behavioural response thresholds, threat-sensitivity and acquired predation recognition

Behaviour ◽  
2006 ◽  
Vol 143 (7) ◽  
pp. 877-889 ◽  
Author(s):  
Reehan S. Mirza ◽  
Maud C.O. Ferrari ◽  
Joseph M. Kiesecker ◽  
Douglas P. Chivers
Keyword(s):  
Threshold Concentration ◽  
Alarm Cues ◽  
Bufo Americanus ◽  
American Toad ◽  
Chemical Alarm Cues ◽  
Selective Forces ◽  
Response Thresholds ◽  
Innate Predator Recognition ◽  
Toad Bufo ◽  
Predator Odour

AbstractPredation is one of the most important selective forces acting on prey animals. To respond adaptively to predation threats and increase their chances of survival, prey animals have to be able to recognize their potential predators. Even though a few studies demonstrated innate predator recognition, the vast majority of animals have to rely on learning to acquire this information. Often aquatic prey animals can learn to recognize predators when they detect conspecific alarm cues associated with cues from a novel predator. In this study, we exposed American toad (Bufo americanus) tadpoles to varying concentrations of chemical alarm cues (cues from injured conspecifics). We identified a concentration of cues which caused an overt antipredator response (supra-threshold concentration) and a lower concentration for which the prey failed to exhibit a response (sub-threshold concentration). In a second experiment, we attempted to condition the tadpoles to recognize the odour of larval dragonflies (Anax sp.) by pairing the dragonfly odour with either the sub-threshold concentration or the supra-threshold concentration of alarm cues. In both cases, the tadpoles learned to recognize the predator based on this single pairing of alarm cues and predator odour. Moreover, the intensity of the learned response was stronger for tadpoles conditioned with the supra-threshold concentration of alarm cues than the sub-threshold concentration. This is the first documented case of this mode of learning in anuran amphibians. Learned recognition of predators has important implications for survival.

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