Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Behavioural Ecology🦓🐝🐒 > Optimal Foraging Theory > Flashcards

Optimal Foraging Theory Flashcards

1
Q

What is optimality theory?

A

describes which behavioural strategy, after weighing up the costs and benefits, maximises fitness

It aims to describe how traits are optimal for survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 factors involved in optimality?

A
  • Decisions - selecting a behavioural option
  • Currency - what is being maximized?
  • Constraints - behaviour, morphology, physiology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 2 main types of foragers

A

Generalists

Specialists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are generalists?

A

Predators that have adapted to locate and consume various prey, likely to fluctuate in abundance during their lifetime

Eat variety of prey

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are specialists?

A

Predators that are adapted to exploit one or several specific food items that have stable populations and are predictably present

Eat one type of prey

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What factors do generalist predators look for in prey?

A

Relative abundant or profitability (i.e: how much time/ energy is spent for energy reward)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name a species that is a generalist predator?

A

Starfish
- Prefers mussels but will eat barnacles

Raccoon
Cockroaches
Crows
Brown Bears
Foxes
Wolves
House Fly 
Coyote
Rats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of forager is a starfish?

A

Generalist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why do generalists spend less time foraging?

A

So they have less predation risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When would you find specialist predators?

A

When prey is abundant and predictable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

If prey is abundant and predictable, what type of predator will be present?

A

Specialist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

If prey fluctuates in abundance, which type of predator will feed on it?

A

Generalists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the richest food sources?

A

The species that are protected from other species the most (i.e: have the least predators)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Name a species that is a specialist

A

Monophagous koala (eats eucalyptus leaves)
Venus flytrap
Pandas (bamboo)
Nudubranchs/ sea slugs (eat sea aneomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name a species that is a generalist

A

Racoons (berries, insects, eggs, small mammals)
Whitetail Deer (herbivore - variety of plants and trees)
Coyote (anything with meat)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are nudibranchs specialists?

A

They can absorb the cnidocysts of sea aneomes and deposit them into their bodies for defence

The cnidocysts are poisonous and not eaten by anything else.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do starlings show about optimal time spent foraging?

A

Time spent foraging does NOT equal the amount of food collected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In breeding starlings, what is the currency of foraging in optimal foraging theory?

A

The maximum rate of delivery of food to nestling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the marginal value theorem (MVT)?

A

The Marginal Value Theorem is an optimality model that describes the strategy that maximizes gain per unit time, in systems where resources, and thus rate of returns, decrease with time.

20
Q

Why must there be an optimal foraging time limit?

A

Because the more time spent foraging = more energy used.

If there is more energy expended than gain from food it will be too costly.

21
Q

What can the Marginal Value Theorem predict?

A

how much time an individual will spend searching a particular patch of habitat before moving on to a new one

22
Q

In general, what are the 2 factors that will cause an individual to stay on a patch longer?

A

1) if patches are further apart (energy used to travel between)
2) Current patches are poor in resources

23
Q

What is the MVT equation?

A

Slope = Food/ Total Time

24
Q

What is the following equation for:

Slope = Food/ Total Time

A

Marginal Value Theorem

25
Q

How do dung flies demonstrate optimality in copulation?

A

Longer time spent copulating = more eggs fertilised
BUT
Longer time spent copulating = more opportunities missed elsewhere

26
Q

How do crows demonstrate optimality with whelks?

A

Crows hunt whelks at low tides
Smash shells on rocks to expose flesh by dropping from a certain height
Zach (1979) observed that crows choose largest whelks only and drop from ~5.2 meters on average
Shows optimal dropping height for energy gained was 5.2 meters

27
Q

How do shore crabs demonstrate optimality?

A

They will pick mussel sizes based on which gives them the highest rate of energy vs time spent breaking shells

Larger mussels = lots of energy breaking shell - less profitable in energy yield

Smaller mussels = easy to crack, contain little energy

28
Q

What are the 3 factors that affect optimal prey choice

A
  • Energy values
  • Handling time
  • Search time
29
Q

When hungry and non-hungry sticklebacks are placed in a small tank with different prey densities, what happens?

A

Very hungry stickleback chose high prey densities

Less hungry sticklebacks chose lower prey densities

30
Q

Why do less hungry sticklebacks chose lower prey densities?

A

Because they need to look out for predators

31
Q

how can larger groups increase individual benefit?

A

Improves foraging success
Predator protection
Parental care
Altruism

32
Q

How can larger group sizes cause a cost to individuals?

A

Increased resource competition
Diseases
Stand out to predators

33
Q

How do lions show the cost and benefit of group sizes?

A

larger lion prides increase capture success but means there are more mouths to share food with

34
Q

What did Caraco et al (1980) find about flock sizes in yellow-eyed juncos? (3)

A

Flocks sizes change with costs of climate and predation

Fighting increases at higher temperatures in larger flock sizes

Extra scanning increases at large flock sizes in presence of a hawk

35
Q

What did Wynne-Edwards (1962) suggest about offspring number in tits?

A

Offspring numbers were adjusted so populations didn’t overuse environmental resources

36
Q

What is phenotypic plasticity?

A

the ability of a genotype to give a range of phenotypic expressions under different environmental conditions.

37
Q

What is an example of phenotypic plasticity?

A

Physical:
- water fleas that develop a spiny helmet in the presence of predators

Behavioural phenotypic plasticity:
- Alternative mating strategies

38
Q

Is animal behaviour considered to be phenotypic plasticity?

A

Yes

39
Q

What can trigger phenotypic plasticity?

A

Environmental conditions
Food availability
Mate availability

40
Q

What does Caraco et al (1980) suggest causes Yellow-Eyed Juncos flock size to change? (2)

A
  • Climate

- Predation

41
Q

At higher temperatures, what happens to Yellow-Eyed Juncos’ behaviour?

A

Dominants increase aggression

Means flocks size benefits from being smaller

42
Q

What are the 3 main types of alternative mating tactics?

A
  • Female mimicry (by males)
  • Sneaking behaviours (in males)
  • Force Copulation
43
Q

What is the GUT in MVT

A

The Giving Up Time

= the interval of time between when the animal last feeds and when it leaves the patch

44
Q

What is GUD in MVT?

A

Giving Up Density

= the food density within a patch when the animal chooses to move on to other food patches

45
Q

If the travelling time decreases, what happens to the slope gradient?

A

It gets steeper

  • Less time travelling = (less energy wasted) more time foraging = more food found
46
Q

What does MVT describe?

A

It describes the behavioural strategy that optimizes gain per unit time

Behavioural Ecology🦓🐝🐒 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions