Prey

views updated May 14 2018

Prey

Prey refers to any living entities that are hunted and consumed by predators. Usually the term is used in reference to animals that are stalked, killed, and consumed by other animals, as when a deer is killed by a mountain lion. However, plants may also be considered to be the prey of herbivorous animals, and hosts may be considered the prey of their parasites .

Often, predators are important sources of mortality for populations of their prey. As such, predators may act as significant agents of natural selection , with some prey individuals being favored because they are less vulnerable to predation, while less-fit individuals of the same species suffer a disproportionate risk of mortality from this source. If differences among individuals in the vulnerability to predation have a genetic basis, then evolution will occur at the population level, and the prey will become more difficult to capture. This evolutionary change in the vulnerability of prey in turn exerts a selective pressure on the predators, so that the more capable individual hunters are favored and the population of predators becomes more effective at catching prey. This is an example of coevolution of populations of predators and prey.

There are limits, however, to how evasive prey can become, and to how effective predators can become. Eventually, extreme expression in the prey of anatomical, physiological, or behavioural characteristics that help to reduce the risks of predation may become maladaptive in other respects. For example, adaptive changes in the coloration of prey may make them more cryptic, so they blend in better with the background environment and are therefore less visible to predators. However, in many species bright coloration is an important cue in terms of species recognition and mate selection, as is the case of birds in which the males are garishly colored and marked. In such cases, a balance must be struck among adaptations that make prey more difficult to catch, and those that are important in terms of coping with other environmental or biological factors that exert selective pressures.

Predator-prey associations of plants and herbivores also develop coevolutionary dynamics. To deter their predators, plants may evolve bad tastes, toxic chemicals, or physical defenses such as thorns and spines. At the same time, the herbivores evolve ways to overcome these defenses.

Predator satiation refers to a situation in which prey is extremely abundant during a short or unpredictable period of time, so that the capability of predators to catch and eat the prey is overwhelmed. For example, to reduce the impact of predation of their fruits , many species of plants flower and seed prolifically at unpredictable times, so herbivores cannot collect and consume all of the fruits, and many seeds survive. There are also many animal-prey examples of predator satiation. For example, metamorphosis of the larval stages of many species of frogs and salamanders is often closely synchronized, so that most individuals transform and leave the breeding pond at about the same time. This is a very risky stage of the life history of these animals, and although many of the individuals are predated upon, the ability of the predators to catch and process this superabundant prey is limited. Consequently, many of the recently transformed frogs and salamanders manage to survive.

Bill Freedman

Prey

views updated May 21 2018

Prey

Prey refers to any individuals that are hunted and consumed by predators. The term is typically used in reference to animals that are stalked, killed, and consumed by other animals, as when a deer is killed by a mountain lion. However, plants may also be considered to be the prey of herbivorous animals, and hosts may be considered the prey of their parasites.

Predators may act as significant agents of natural selection, individuals are alive to produce more off spring if they are less vulnerable to predation. If the reason that an individual is less vulnerable to predators has a genetic basis, then its offspring will inherit traits that make them less vulnerable to predation as well. Evolution will occur in the population, and the prey will become more difficult to capture. This evolutionary change in the vulnerability of prey in turn exerts a selective pressure on the predators, so that the more capable individual hunters are favored and the population of predators becomes more effective at catching prey. This results in coevolution of populations of predators and prey.

There are limits, however, to how evasive prey can become, and to how effective predators can become. Eventually, extreme expression in the prey of anatomical, physiological, or behavioral characteristics that help to reduce the risks of predation may become maladaptive in other respects. For example, adaptive changes in the coloration of prey may make them more cryptic, so they blend in better with the background environment and are therefore less visible to predators. However, in many species bright coloration is an important cue in terms of species recognition and mate selection, as is the case with some species of birds in which the males are garishly colored and marked. For these populations, selective pressures will balance adaptations that make prey more difficult to catch, and those that are important in terms of coping with other environmental or biological factors.

Predator-prey associations of plants and herbivores also develop coevolutionarily. To deter their predators, plants may evolve bad tastes, toxic chemicals, or physical defenses such as thorns and spines. At the same time, the herbivores evolve ways to overcome these defenses.

Predator satiation refers to a situation in which prey is extremely abundant during a short or unpredictable period of time, so that the capability of predators to catch and eat the prey is overwhelmed. For example, to reduce the impact of predation of their fruits, many species of plants flower and seed prolifically at unpredictable times, so herbivores cannot collect and consume all of the fruits, and many seeds survive. There are also many animal-prey examples of predator satiation. For example, metamorphosis of the larval stages of many species of frogs and salamanders is often closely synchronized, so that most individuals transform and leave the breeding pond at about the same time. This is a very risky stage of the life history of these animals, and although many of the individuals are preyed upon, the ability of the predators to catch and ingest this superabundant supply is limited. Consequently, enough juvenile frogs and salamanders survive to maintain their populations.

Bill Freedman

prey

views updated May 18 2018

prey / prā/ • n. an animal that is hunted and killed by another for food: the kestrel is ready to pounce on unsuspecting prey. ∎  a person or thing easily injured or taken advantage of: he was easy prey for the two con men. ∎  a person who is vulnerable to distressing emotions or beliefs: the settlers become prey to nameless fears. ∎  archaic plunder or (in biblical use) a prize.• v. [intr.] (prey on/upon) hunt and kill for food: small birds that prey on insect pests. ∎  take advantage of; exploit or injure: this is a mean type of theft by ruthless people preying on the elderly. ∎  cause constant trouble and distress to: the problem had begun to prey on my mind.PHRASES: fall prey to be hunted and killed by: small rodents fell prey to domestic cats. ∎  be vulnerable to or overcome by: he would often fall prey to melancholy.DERIVATIVES: prey·er n.

prey

views updated Jun 27 2018

prey that which is taken by violence; animal hunted or killed XIII; fig. victim XIV. ME. praie, preie — OF. preie (mod. proie):— L. præda booty, prob.:- *praiheda, f. prai, præ PRE- + *hed-, base of præhendere seize.
So prey vb. XIII. — OF. pre(i)er :- late L. prædāre, for earlier prædāri.

prey

views updated May 14 2018

prey An animal that is a source of food for a predator. See predation.

prey

views updated Jun 11 2018

prey See predation.

prey

views updated Jun 11 2018

prey See PREDATION.

prey

views updated Jun 08 2018

prey See PREDATION.