Lecture 7 - Optimal Foraging Theory

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Questions and Answers

What is foraging?

The sum of processes involved in the acquisition of energy and nutrients.

Which of the following describes the foraging cycle?

Search - detection of prey

Pursuit - leads to physical contact with prey

Handling - leads to consumption of prey

All of the above (correct)

What happens in the assessment phase of foraging?

The animal decides whether to continue the cycle or return to searching.

Incomplete cycles guarantee a reward.

False Signup and view all the answers

What does investment refer to in foraging?

Search, pursuit, and handling. Signup and view all the answers

What is patch exploitation?

Forage from energy dense patches. Signup and view all the answers

What is central place foraging?

Bees taking pollen back to the hive Signup and view all the answers

What does foraging theory help understand?

Fitness consequences and foraging decisions that maximize relative fitness. Signup and view all the answers

What does optimal foraging theory predict?

Organisms forage to maximize their net energy intake per unit time. Signup and view all the answers

What does the equation R=V/(d+h) represent?

Rate of energy gain = prey value / (interval between discoveries + pursuit and handling time). Signup and view all the answers

Simultaneous choice models involve choosing prey one at a time.

False Signup and view all the answers

Sequential choice models are about choosing prey detected one at a time.

True Signup and view all the answers

What does the Marginal Value Theorem describe?

How an animal might decide to leave a foraging patch. Signup and view all the answers

What is a carnivore?

An animal that eats 'meat', including all types of animals. Signup and view all the answers

What does an herbivore eat?

An herbivore eats 'plants', including algae. Signup and view all the answers

What is an omnivore?

An animal that eats everything - plants and meat. Signup and view all the answers

What can foraging habitats define?

Diets such as planktivore, benthivore, and aerial insectivore. Signup and view all the answers

What characterizes a specialist in foraging?

Low dietary diversity. Signup and view all the answers

What characterizes a generalist in foraging?

High dietary diversity. Signup and view all the answers

What are the benefits of foraging?

Both A and B Signup and view all the answers

What are the costs of foraging?

Both A and B Signup and view all the answers

What is the net rate of energy gain (NREG)?

The difference between the total intake and the expenditure of energy to achieve that intake. Signup and view all the answers

What is a foraging patch?

An area where prey are aggregated. Signup and view all the answers

What do patchy food sources relate to?

How the use of patches affects predation rates. Signup and view all the answers

What characterizes central place foraging?

Animals move out from one location to forage and return with food to that location. Signup and view all the answers

Study Notes

Foraging Concepts

Foraging involves processes to acquire energy and nutrients.
The foraging cycle consists of search, pursuit, and handling phases.

Decision-Making During Foraging

The assessment phase is crucial for determining whether to continue pursuing prey or resume searching.
Incomplete cycles may occur when the forager does not obtain a reward.

Investment and Energy Management

Investment in foraging includes search, pursuit, and handling efforts.
Patch exploitation focuses on foraging from energy-dense areas to maximize returns.

Central Place Foraging

An example is bees transporting pollen back to their hive, which allows for empirical study of foraging success and food quality.

Underlying Theory

Foraging theory examines how organisms plan their search for food, weighing when to stop foraging based on fitness consequences.
Optimal foraging theory suggests creatures will forage to maximize their net energy intake per unit time, linking energy gain with reproductive success.

Calculating Energy Gain

The formula R=V/(d+h) represents the rate of energy gain as prey value divided by the sum of discovery, pursuit, and handling times.

Choice Models in Foraging

Simultaneous choice models help determine which prey to select when multiple options are available.
Sequential choice models involve detecting prey one at a time to decide whether to pursue or continue searching.

Marginal Value Theorem

This theorem helps explain how foraging animals choose to leave a resource patch once the yield decreases.

Dietary Classifications

Carnivores primarily eat animals; examples include piscivores (fish eaters) and insectivores (insect eaters).
Herbivores primarily consume plants, with subdivisions based on plant parts, like folivores (leaf eaters) and frugivores (fruit eaters).
Omnivores eat both plants and animals, demonstrating dietary flexibility.

Foraging Habitats and Specialization

Foraging habitats can define dietary needs, including planktivores and benthivores.
Specialists have low dietary diversity, while generalists maintain high dietary diversity.

Benefits and Costs of Foraging

Benefits include energy and nutrient acquisition.
Costs involve energy expenditure, time requirements, and exposure to risks such as predators.

Energy Gain Metrics

The net rate of energy gain is calculated by subtracting energy expenditure from total intake.
Measures of foraging success include net rates and nutrient acquisition.

Foraging Patches and Ecological Implications

A foraging patch is characterized by aggregated prey, leading to reduced search times.
Patchy food sources significantly influence predation rates and ecological models of foraging behavior.

Central Place Foraging Dynamics

Central place foragers travel to distant locations to gather resources and return to a fixed site, which involves travel, storage, and transport strategies.

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Description

This quiz covers key concepts of Optimal Foraging Theory, including definitions of foraging, the foraging cycle, and the assessment phase. It is designed to help students reinforce their understanding of the processes involved in energy and nutrient acquisition in animals.