Researchers have long pursued theories to explain species' diversity. These theories have focused on quantifying adaptation, fitness, and natural selection through observing an animal's feeding behaviors. The assumption is that feeding behaviors are reflections of these internal processes. Using behavior as a mechanism of adaptation in a feedback loop creates an interactive system between an animal's phenotype and its environment.
MacArthur and Pianka (1966) first proposed an optimal foraging theory, arguing that because of the key importance of successful foraging to an individual's survival, it should be possible to predict foraging behavior by using decision theory to determine the behavior that would be shown by an "optimal forager"—one with perfect knowledge of what to do to maximize usable food intake. In their paper, a graphical model of animal feeding activities based on costs versus profits was developed. A forager's optimal diet was specified and some interesting predictions emerged. Prey abundance influenced the degree to which a consumer could afford to be selective because it affected search time per item eaten. Diets should be broad when prey are scarce (long search time), but narrow if food is abundant (short search time) because a consumer can afford to bypass inferior prey only when there is a reasonably high probability of encountering a superior item in the time it would have taken to capture and handle the previous one. Also, larger patches should be used in a more specialized way than smaller patches because travel time between patches (per item eaten) is lower.
Succinctly, this heavily referenced paper in evolutionary biology presented three concepts:
(1) How long a predator will forage in a specific area?
(2) Influence of prey density on the length of time a predator will forage in an area.
(3) Influence of prey variety on a predator's choice of acquired prey.
These concepts describe a predator's behavior as a function of its relationship with the prey it acquires. Fundamental conditions in these concepts influencing the predator-prey relationship are time foraging and prey availability. Within these concepts, MacArthur and Pianka embodied the study of differential land and resource use in a specific field of study: optimal foraging theory.
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