Lecture 5

Question 1

What is Optimal Foraging Theory

Answer 1

1. Assumptions that Behavioural decisions made to maximize long term benefits

Question 2

What are the assumptions of Optimal Foraging Theory

Answer 2

4 Assumptions
1.Specific Prey types have profitability (E / Unit of handling)

2. Handling time = mutually exclusive of search time
3. Profitability of prey can be learned. Can be used to compare different types of prey.
4. Use learned information to accept or reject. E/T

Question 3

Predictions of OFT

Answer 3

1. Foragers always accept most profitable food item
2. Accept successively less profitable items only when E/T would otherwise fall below mean E/T
3. Low quality prey always rejected

Question 4

Examples of OFT

1. Blue Gill Sunfish?
2. Largemouth Bass?

Answer 4

1. Bluegill sunfish - Generalist

Exposed to dif. class size of daphnia
Choose Largest Daphnia, Choose smaller only when abundance is greater than large. (less time to forage)

Choose other food Items at all times.

2. Largemouth Bass - Specialist

Choose largest daphnia, choose smaller only when abundance is greater than large

Reject food items not in “optimal set”

Question 5

Explain Main Differences between

Generalist Vs. Specialist

Answer 5

If Pj P + S = New Food

Where

Pj = Time needed to catch food
P = Average Pursuit time
S = Average Search time
j = Particular Food Item

S high and P low = Generalist Selection

P is High and S is low = Specialist

Question 6

Flexible Strategies

Answer 6

Obligate Generalist:

S High P Low

Flexible

S moderate, P Moderate

Obligate Specialist

S low and P high

Question 7

What is Obligate Generalist

Answer 7

Search time is High and Pursuit time is low

Question 8

What is Flexible Foraging Strategy.

Answer 8

Search and Pursuit time are both moderate

Question 9

What is Obligate Specialist

Answer 9

Search time is low but Pursuit time is High

Lion, Bee

Question 10

Constraints of Foraging Strategy

Answer 10

Physiological Constraint
(Sequential Specialists)

Environmental Constraints
(Opportunistic Foragers)

Question 11

Optimal Strategy affected by which factors

Answer 11

1. Predation Pressure
2. Hunger Level
3. Learned Food preferences - preferred item may not be always optimal
4. Parasite load

Question 12

Provide Example of Predation Pressures

Answer 12

Guppies shift to less profitable night time Foraging

Question 13

What are the links between Foraging and Risk?

Answer 13

1. Increase in Risk of foraging = more cautious foraging
2. Neophobia Vs. Neophilia

Learning and Neophobia is negatively correlated.

Link between risk taking and exploration

Question 14

Ideal Free Distribution

Answer 14

Where to Forage

1. Profitability of Patch vs. Predator number
2. Pays to switch for dense, high quality patch, to sparse low quality patch ( more prey per forager)

Question 15

What is Competition Exclusion

Answer 15

Number of individuals a particular habitat can support is limited since.

increased # = Less resources per individual

Increased # = increased competition = reduced E/T