5.4: Enemies - Predation
At its simplest, we can consider predation (or herbivory) to be a function of predators (or herbivores) detecting, capturing, and consuming prey (or plant) individuals:
\[P\text{(predation)} = P\text{(detection)}\times P\text{(capture)} \times P\text{(consumption)}\]
where P() is the probability of each factor occurring. Consequently, predators/herbivores have many adaptations for increasing these terms and prey/plants have many adaptations for decreasing them. For example, predators may increase detection through enhanced senses, such as the exceptional eyesight of raptors, while prey may decrease detection through camouflage. Predators may increase capture through strategies like pack hunting in wolves, while prey may decrease capture through defensive armor or spines. Snakes are able to unhinge their jaws in order to increase the consumption of very large prey items, while some plant leaves contain compounds such as tannins that are very difficult to digest, decreasing herbivores’ consumption ability and deterring herbivory.
All of the adaptations described in the paragraph above result in trade-offs. Energy and other resources invested by prey in defensive structures or toxic compounds cannot then be put towards growth and reproduction. For predators, strategies such as pack hunting may increase the likelihood of successful capture, but also means that consumption is shared across numerous individuals.