Predation - Wikipedia
The roles of dissolved oxygen and turbidity on predator–prey interactions have been Within central North America, placement of automated data loggers (YSI . For example, unlike terrestrial environments, there should be little significant change alter predator–prey relationship[Proceedings of the Royal Socie ]. Most animal species are engaged in a predator–prey relationship by predator behavior (for example, hunting mode) and prey behavior (for example, .. The funders had no role in study design, data collection and analysis. how predators affect prey populations, and vice-versa; what stabilizes The hare -caribou-lynx relationship in Newfoundland is a complex example of such a.
If, for instance, food supply is altered as a result of lack of prey, it will reflect on the population of predatory species, as they will find it difficult to reproduce in times of food scarcity.
And like we said earlier, if the population of predators comes down, herbivores will run a riot in the ecosystem. It's a classic example of the survival of the fittest. In stark contrast to the cheetah-gazelle relationship is the relationship between African wild dogs and zebras. Wild dogs might be small, but they make up for it by resorting to pack behavior and their remarkable stamina. The strategy is simple: As for zebras, they have the camouflage working in their favor, making it difficult for their predators to isolate and attack an individual.
10 Dumbfounding Examples of Predator-Prey Relationships
After analyzing the number of lynx and hare pelts brought in by hunters, Canadian biologist, Charles Gordon Hewitt came to a conclusion that the two species are highly dependent on each other, such that the population of the Canadian lynx rises and falls with a rise and fall in the snowshoe hare population. Further research revealed that it was the food shortage resulting from the decline in hare population that affected the reproduction rate of this lynx species. While wildebeests and Cape buffaloes form a major chunk of their diet, African lions are also known to prey on warthogs, especially when they are easily available.
From the researchers' point of view, the relationship between wolves and moose on the Isle Royale gives the best picture of predator-prey relationships, as moose are almost the only prey for wolves on this isolated island. After studying their relationship for decades, researchers have realized that the food shortage resulting from wolves eating too many moose, keeps a check on the wolf population as well.
In the marine biome, the great white shark is the apex predator. It usually preys on elephant seals. For seals, the best line of defense is to stay on land. For the great white shark, its exceptional hearing skills help to locate the seal.
It is not always possible for the seal to stay out of water, lest it can die of hunger. The moment it gets into the water, it is on the great white's radar. It all comes down to whoever blinks first. In the freshwater biome, an osprey catching a fish will be a perfect example of predator and prey in action. This bird is found nearly everywhere where it can find fish to prey upon. With its exceptional eyesight, the osprey can see any movement in the water.
It strikes at a lightning speed and pulls the fish out of water, thanks to its opposable claws and the sharp spiny scales on its toes. As for fish, their best defense is to avoid shallow water.
In the tundra biome, we have an interesting example in the form of the relationship between the Arctic fox and lemmings; interesting because lemming population is cyclic, i. Recent work has shown that individuals on rock walls are ambush hunters, jumping from rock to rock, but that individuals in sandy habitats engage in active running pursuit To facilitate jumping, individuals on rock walls have longer hindlimb-to-forelimb ratios than do their sandy habitat counterparts These hunting mode differences lead to dietary differences, where sandy habitat hunters consume more sedentary prey and rock wall hunters consume more mobile prey Eurasian perch compete for resources within pelagic habitats and this leads to within-population divergence in habitat usage such that some population members use littoral zones This habitat shift leads to morphological shifts, where individuals in pelagic habitats tend to have a streamline body form suited for pursuit whereas littoral individuals have deeper rounded body forms more suitable for slower maneuverability Pelagic individuals in turn tend to have a narrower diet breadth and specialize less and thus have more stable trophic interactions than do littoral individuals who occupy a habitat that provides a higher diversity of resources A biomechanics perspective reveals the importance of considering functional traits in action, yet many synthetic frameworks that tend to classify species by functional traits treat those traits as fixed characteristics of species 4.
This merely substitutes one classification scheme taxonomic for another functional traits and thus risks substituting one form of typology species for another functional traits 4.
This limits the insights that can come from a functional trait approach. Newer functional trait approaches help overcome typological thinking by recognizing that species comprise individuals that vary in their traits 49252744 Moreover, individuals can flexibly adjust the expression of their traits to maximize survival and reproduction fitness 4 Both considerations help us understand and predict context dependency.
For instance, whenever a predator—prey relationship is non-linear, the mean expected net effect of a species may not simply reflect the species mean expected value of the functional trait 27 The net effect may depend on the magnitude of trait variation and the shape of the trait distribution for example, normal versus skewed 27 Individuals within a population may also adaptively adjust their trait expression to match their phenotype to the new environmental context Ultimately, then, a functional trait approach dynamically connects evolutionary ecology with community ecology 4394044reinforcing the idea that a predator—prey relationship is an adaptive game The evolutionary ecology of functional traits Understanding of predator—prey interactions fundamentally changed when it was recognized that predators can exert strong non-consumptive effects on prey 46 This realization led to the general principle that predator—prey interactions are essentially an evolutionary ecological trade-off game involving trait changes via phenotypic plasticity and adaptation via selection 4 Early work largely explored the trade-off in terms of prey behavioral and morphological plasticity Figure 1 747 Hence, prey are not unwitting victims.
They behaviorally evade predators by becoming vigilant, shifting their foraging time budget, or shifting between foraging habitats and refuge habitats. Prey also induce anti-predator defense morphology, becoming cumbersome to handle by gape-limited predators, such as through the production of spines by zooplankton or through accelerated development by tadpoles to reach a predation size refuge. Prey could also become better at evading predators such as by changing the development of musculature related to swimming 47 Predators in turn change their tactics to try to overcome prey defenses, setting up an eco-evolutionary game 16 More recent work shows that plastic responses of prey to perceived predation risk are fundamentally triggered by physiological stress Figure 1.
Physiological stress is an evolutionary conservative coping mechanism involving neuroendocrine responses that put prey in a heightened state of alertness and agility 2122 If chronic, predation-induced stress can cause prey to change their locomotor biomechanics to enhance escape performance Moreover, chronic stress can lead to chronically elevated metabolic rate 214951 — Whether or not prey become chronically stressed can depend on the hunting mode of their predator.
Sit-and-wait and sit-and-pursue predators may elicit persistent cues of their presence, triggering a heightened state of alertness and agility 54but a chronic stress response would be energetically wasteful when facing widely roaming predators where encounter frequency is low Elevated metabolism arising from perceived predation risk could change organismal nutrient demand and hence the kinds of resources consumed by prey 214951 — 53creating a physiological trade-off in nutrient allocation between maintenance respiration and both growth and reproduction which alters organismal fitness.
Thus, physiological plasticity to increase escape performance entails growth and reproductive costs, which can carry over to influence offspring performance through such things as maternal effects 224850but how those costs are borne depends on the capacity of individuals to exhibit adaptive behavior, which is reflected by within-population variation in the degree to which individuals can respond adaptively.
Classic approaches examining trait effects in communities have assumed that traits of an individual are fixed, such that differences in response among phenotypes are continuous and quantitative 234555 This leads to qualitative differences in the way individuals reconcile a trade-off between foraging gains and predator avoidance 44 For example, individuals in low food environments or in low energetic state or poor body condition may be motivated to play the trade-off game differently than individuals in high food environments or in high energetic state or high body condition.
Low-energetic-state individuals may accept greater predation risk because starvation risk outweighs predation risk. Alternatively, high-energetic-state individuals may opt to enhance their avoidance of predators 5758 because they can ride out pulses of risk or are protecting the body condition asset protection that they have already built up 59 — Hence, individuals may be perceived as being shyer or bolder depending on their nutritional or energetic state Predators may take advantage of these differences.
In spring, predatory barn owls hunt high-energetic-state gerbil prey prey with large energy storesgiving high energetic return for their foraging effort As summer progresses, high-energetic-state gerbils become more vigilant than low-energetic-state gerbils While owls still prefer high-energetic-state individuals, they increasingly hunt low-energetic-state individuals, thereby equalizing the hunting pressure on low- and high-energetic-state individuals Recent research shows that predator and prey personalities essentially amplify outcomes of general predator hunting mode—prey mobility interactions.
Personality becomes a key source of trait variation within populations. For example, northern pike predator—stickleback prey interactions involve personality-dependent reciprocal behavioral plasticity Pike orient and position themselves to strike moving sticklebacks. Sticklebacks in turn freeze in place to become cryptic to fend off an attack.
Pike orient longer before attacking when sticklebacks freeze, and the longer stickleback freeze the longer it takes before pike attack Hence, individuals that freeze longer shyer personalities tend to have higher survivorship, but that outcome is mediated by pike neurophysiology.
Individual pike with higher resting metabolic rates higher energy demands tend to be more aggressive and strike sooner than individuals with lower metabolic rates Predator aggressiveness then favors bolder stickleback individuals that freeze for shorter durations and move to escape.
Pike metabolic rate also determines hunting mode and habitat selection: More aggressive individuals also tend to have larger eyes for visual acuity Personality also determines contingent outcomes in interactions between black widow spider predators and cricket prey. Bold crickets survive more poorly when facing bold spiders than when facing shy spiders, and vice versa Bold crickets seem to escape from spider webs long before shy spiders can subdue them but are quickly captured by bold spiders Shy crickets are less likely to move enough to encounter and be caught in webs Prey personality can influence outcomes with different predator species as well, as exemplified by interaction between mud crab prey that face active hunting blue crabs and sit-and-wait ambush toad fish Bold mud crabs are more likely to succumb to blue crabs because they spend more time outside of refuge habitats, whereas shy mud crabs spend more time in refuge habitats where toad fish tend to lie in wait These cases all illustrate how different personality types of predators can select for different prey personality types, preserving phenotypic diversity in both predator and prey populations Phenotypic diversity is also the basis for rapid evolutionary change 67 — 69which can lead to another form of state dependence—local adaptation of morphology, behavior, or physiology to environmental context A case in point is changes in biomechanical performance in an Anolis lizard species.
As a clade, arthropod-eating Anolis lizard species have adapted to occupy different habitat locations, including the ground, trunks of bushes, and branches. Body and limb morphology can discern which habitat is used.
Experimental introductions of a ground-dwelling predatory lizard onto small islands revealed that such differentiation in ecomorphology-habitat association could evolve within-species as well The introduced predator selected those individuals of a ground rock-dwelling ambush Anolis species that were poorly capable of climbing on trunks and branches This triggered plastic changes toward shorter limbs and longer digits of surviving Anolis to facilitate active maneuvering on thin branches and catching prey in the higher vegetation canopy.
Plasticity became an antecedent to locally adaptive evolutionary change in Anolis form and functional role within about 10—15 years, relative to those on control islands The interplay between plasticity and adaptive evolution is revealed further in a zooplankton, the water flea Daphnia, that has faced different predation regimes Daphnia produce eggs that often lie dormant in lake sediments.
Generations of eggs, layered upon one another in the sediment, thus store key information about historical changes in environmental conditions within a lake. Laboratory experiments hatched Daphnia individuals from different sediment layers that represented periods before, during, and after fish presence.
When the hatched individuals were exposed to fish cues, they expressed different degrees of plasticity and adaptation in vulnerability traits depending on if and when their parental populations were exposed to fish predators within their natal lakes Moreover, the degree of plasticity expressed by hatched individuals varied depending on the historical association with fish predators This again underscores the need to examine traits in action, including how different evolutionary processes drive the trait changes as environmental context changes in order to enhance predictive understanding of complexity underlying predator—prey dynamics and interactions.
The Anolis and Daphnia examples, as well as classic studies of Trinidadian guppies evolving different body morphology and coloration to cope with different predation regimes 70reveal that evolutionary processes can be quite rapid. Evolutionary processes can operate contemporaneously with ecological processes, thereby creating eco-evolutionary feedbacks among environmental contexts 6771 — Rapid evolution in response to changing environmental contexts has been documented in a metapopulation of herbivorous stick insect species.
In this system, local populations of the stick insect have heritable body coloration patterns that match local patches of their shrub host plants One shrub has lance-shaped leaves, and the other has ovoid leaves.
Individual stick insects are cryptic to bird predators on lance-leaved shrubs by expressing a dorsal stripe and are cryptic on ovoid-leaved shrubs by expressing a solid green color When patches of the different shrubs are in close proximity, gene flow between patches can cause maladaptation in local populations because of misaligned expression of insect body coloration in the shrub 38but more isolated populations exhibit local adaptation.
This preserves an eco-evolutionary process that creates a mosaic of stick insect ecotypes across a landscape Another recent case involves a lake-dwelling damselfly species.
Ancestral forms of the species evolved to coexist with predatory fish 74but this damselfly species has repeatedly invaded fishless lakes containing dragonfly predators. Heritability and selection studies revealed that the damselfly could evolve different predator coping mechanisms within 45 years Damselfly larvae in fish lakes evade predators by having low swimming propensity and slow swimming speeds, remaining motionless hence cryptic when facing predatory fish that can swim faster Damselfly larvae in dragonfly lakes instead swim faster to outrun their predators The rapid pace of human-caused environmental change such as habitat alteration or facilitation of species invasions has increased the likelihood that predator—prey interactions are occurring between species that have not coevolved.
Consequently, the traits of native predator and prey species may be poorly adapted for the conditions presented by the new species, whether it is a novel predator or a novel prey 75 The new encounters thus could change the relative importance of consumptive and non-consumptive effects that drive the eco-evolutionary game, raising concern about the loss of native predators and prey species and hence the need to manage invasives But here too the capacity for plasticity and rapid evolution may enable predator and prey species to cope with these new challenges and hence persist within the newly formed communities 7277 If this capacity is found to be widespread across predator and prey species, it could change our outlook on the fate of species in a rapidly changing world.
Conclusions There is growing appreciation that variety in the structure and functioning of ecological communities and ecosystems can be strongly dependent upon the evolutionary history of the interacting predator and prey species 67 — 7479 — The extent to which this reflects variation in the expression of species functional traits that can change via plasticity or rapid evolution in response to the changing ecological conditions created by their interactions 446771 remains to be seen, and it will likely be difficult to explain context dependency in the absence of taking an adaptive functional trait approach 40 This fundamentally requires a new view of predators and prey as organisms, each comprising a suite of traits whose collective function is coordinated—to capture and subdue or evade and defend—as they engage with and adapt to each other in an evolutionary ecological game 183940 Thus, understanding the variety inherent in predator—prey interactions requires examining how the game is played in different contexts.
This requires taking a new relational experimental approach that observes predator and prey traits in action, requiring analysis of changes in the expression of functional traits within populations of predator and prey species with natural or experimentally imposed changes in ecological contexts 4 Such an approach differs from traditional factorial experimental approaches that merely draw prey individuals with different trait magnitudes for example, body size from single populations and then experimentally expose them either to predators or their risk cues or to cue-free conditions to measure the response of individuals with a given trait.
The expanded eco-evolutionary approach discussed here would need to evaluate the potential for local adaptation among predator and prey populations, which includes local adaptation in the nature and strength of phenotypically plastic responses 446774 This calls for deploying factorial designs using transplant experiments across environmental gradients 445784 Such experiments would draw individual predators and prey from populations in different environmental conditions and compare the nature and strength of their interactions in transplant as well as native sites to understand patterns of adaptive variation across an environmental landscape as well as the community- and ecosystem-level consequences of their context-dependent interactions.
Ultimately, the adaptive game between predator and prey can be likened to an evolutionary play within an ecological theater 86 but which unfolds differently in different theaters contexts 3480 Hence, the play itself is not scripted but rather is an improvisation that depends on how the players choose to enact the play as well as how their acting changes the look of the theater 34 This ultimately depends on the physiological, morphological, and behavioral states of the players Figure 1 as well as how quickly the players adapt their traits to each other and the changing theater.
Hence, the players and their theaters are in perpetual flux, requiring modern analyses of predator—prey interactions to scale from functional traits to whole ecosystems 479 — 82 in order to develop a predictive understanding of the variety inherent in predator—prey systems. Acknowledgments The author thanks David Boukal and Blaine Griffen for helpful comments and feedback on the manuscript.
Notes [version 1; referees: The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. In order to make these reviews as comprehensive and accessible as possible, the referees provide input before publication and only the final, revised version is published.
The referees who approved the final version are listed with their names and affiliations but without their reports on earlier versions any comments will already have been addressed in the published version. The referees who approved this article are: Simple prediction of interaction strengths in complex food webs.
Ecological networks--beyond food webs.