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Sem 2: Behavioural ecology > Week 3 > Flashcards

Week 3 Flashcards

1
Q

What is optimality theory?

A

Theory that seeks to describe how traits are optimal, i.e. they generate the most profitable ratio of fitness benefits to fitness costs

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2
Q

What is the aim of optimailty theory?

A

Optimality theory tries to understand / explain how animals (have evolved to) solve problems by simplifying into quantitative costs and benefits

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3
Q

How would you work out which strategy of more small eggs or fewer larger eggs will be selected for?

A

Fitness benefit = No. of eggs * probability of survival

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4
Q

Are animals conscious calculators?

A

No
Evolution optimizes every organic trait, including behaviour, through natural selection
Optimality can (sometimes) be quantified

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5
Q

What is the ideal free distrubution?

A

Ideal free distribution is a theoretical way in which a population’s individuals distribute themselves among several patches of resources within their environment, to minimize resource competition and maximize fitness

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6
Q

How can you work out an outcome for ideal free distrubution?

A

A graph with number of competitors on x axis and reward per individual on y axis. Negative correlation curv the more competitors the lower the reward

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7
Q

What are the assumptions made about the ideal free distrubution?

A

Its ideal, because animals have complete information about the availability of resources
Its free, because animals are free to go best area ie no outside influence like predators
Under IFD all individuals have equal fitness
Therefore the IFD is a stable distribution

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8
Q

How did they test IFD with sticklebacks?

A

Added food to two areas A had twice the amout of food than be
Predicted that twice as many fish where there’s twice as much food

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9
Q

What was the results of testing IFD in sticklebacks?

A

Average was 3 when food was reduced declined to 2 when rate was doubled increased to 4 fish. There was lag for both responses

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10
Q

Can IFD shown in humans?

A

Ideal free shoppers. people will go to empty queues

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11
Q

What are the benefits of living in groups?

A

Anti-predation
Decreases Inter-specific competition
Thermal advantage
Mobility advantage
Increases information
Increases foraging efficiency

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12
Q

What are the costs of living in groups?

A

Increase intra-specific competition
Interference
Cuckoldry
Increased rate of cannibalism/infanticide
Higher risk of parasites & disease

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13
Q

What is a case study of the downsides of living in groups?

A

Increases swallow paraistes on chicks when colony is large - positive correlation

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14
Q

What is a case study of the upsides of living in groups?

A

Defassa waterbuck
Larger group the larger the total vigilance time
Larger the group the lower the individual vigilance time is

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15
Q

How can living in a larger group increase antipredation?

A

Flock size dictates attack success for goshawks predating woodpigeons.
Trade off - bigger flocks have longer reaction distances

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16
Q

How can flock size change with predator risk?

A

Yellow-eyed juncos increase flock size under greater predation risk

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17
Q

What situations do MVT helps us to understand?

A

An animal exploits resources within discrete sites/patches
Within a patch, returns decrease over time (asymptotic (diminishing) gain curve)
There is a cost in getting to / from the patch

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18
Q

What does MVT stand for?

A

Marginal Value Theorem

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19
Q

What is an example of MVT?

A

Optimal foraging time

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20
Q

How would you calculate otimal foraging time?

A

Energy from food / (Time spent travelling + time spent searching)

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21
Q

What is the relationship for time spent searching for food and amount of food found?

A

A diminishing (asymptotic) gain curve

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22
Q

How would you work out how much time should an animal spend to get most out of the food resource?

A

Draw a line that starts at time spent travelling (x,0) and goes through where time spent searching meets amount of food found on the curve
Work out the number of energy gain / total time
Repeat until you find the highest number

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23
Q

What happens to the MVT number when travel time is lowered?

A

Both search time and the load are lower to maximise rate

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24
Q

What is starling foraging strategy?

A

Breeds in spring
400+ trips per day to feed nestlings
Nestlings mainly get fed leatherjackets

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25
Do starlings behave like it is predicted with MVT theory?
Yes, travel time increases so does load size
26
How else can MVT be applied?
Optimality in the time spent copulating in dung flies
27
What is the case study in dung fly copulation?
Males mate with females on dung heaps The longer a male copulates, the more eggs he fertilises The longer a male copulates, the more opportunities he misses elsewhere
28
How else can optimality and resource selection vary?
With the economics of prey choice. Prey items vary in their cost
29
What did they find about crab size and mussel size influence handling time?
Smaller crabs spend have longer handling times as mussel size increases Large crabs have small handling times with both small and large mussles Medium crabs quickier than smaller crabs but cant access large mussels like large crabs can
30
How does energy gain and handling time impact resouce gain?
Mussel calorific energy gain depends on handling time for different mussel and crab sizes Large crabs can still benefit with spending more time on larger mussels compared to others which have a lower peak prefered size
31
What are the rough optimal times for crabs at different sizes?
Small - 2cm mussels Medium - 2.5 cm mussels Large - 3.3 cm mussels
32
Are crabs optimal?
Nearly - They are slightly lower than predicted could be to do with search time Small - 1.3 cm mussels Medium- 1.7 cm mussels Large - 2.3 cm mussels
33
What is an example of environment impacting behaviour?
John Krebs impacting resource management in great tits vs marsh tits
34
How do great tits manage food resources?
Fat reserves with variable environements increasing body morning weight
35
What is the downside of fat reserves?
Great Tits on bird table exposed to fake predator Increased fat reserves decrease response time to predators Trade off between reducing starvation vs risk of predation
36
What is the disadvantage of external storage?
Larger brains for better memory to remember where food was stored. Larger brains cause increased caloric demand
37
Why are Tribolium good model organisms?
Long history; They’re Coleoptera, 1 in 2 species so broadly applicable; Convenient- cheap and easy to look after
38
What is the definition of dispersal?
Any movement of individuals or propagules with potential consequences for gene flow across space
39
What are propagules?
Vegetative structure that can become detached from parent used in dispersal eg seeds, spores or endospores
40
What is gene flow?
Any movement of individuals, and/or the genetic material they carry, from one population to another
41
What are the popular image for dispersal?
Popular image of dispersal is seed dispersal / dispersal BY animals
42
What are the key traits of animal dispersal?
More active and complex; but essentially the same principles as propagules dispersal
43
What are reasons for dispersal?
To avoid competition Locate scarce resources Avoid predation To find mates To avoid inbreeding
44
What is a case study of animal dispersal?
Inbreeding avoidance in lions Male lions are kicked out of pride and have to compete for control of another pride to avoid inbreeding
45
What are the advantages of dispersal?
Less competition More resources Less predation More mates Less inbreeding
46
What are the potential disadvantages of dispersal?
More competition Fewer resources More predation Fewer mates
47
What are the consequences of dispersal on a individual?
Can increase or decrease: Competition Resources Mates Inbreeding
48
What are the consequences of dispersal on a population?
Can increase genetic variation Spatial structure Metapopulation persistence Range dynamics
49
What is a consequence of no gene flow?
Disturbed landscapes -> habitat fragmentation  -> meta population split into subpopulations --> higher risk of extinction
50
?What is a consequence of gene flow on populations?
Undisturbed landscapes -> larger joined population-> gene flow of individuals around each of the habitats -> increased genetic variation across population -> increased resistance to potential extinction events and also recolonisation of high impacted areas
51
What is range for a species?
The total area in which an animal can surive and live in
52
How can a range for a species change?
Increased genes for dispersal allowing for colonisation External factors changing environmental conditions allowing for new habitats to become accesible
53
What is a case study for habitat range changes?
Human range changes. 2.5 mya located in east and south east africa 500,000 ya colonised rest of Africa, middle east, india, china, south east asia and southern europe 10,000 years colonised rest of word minus remote regions like iceland, new zealand, cold northern regions of canada and siberia
54
What is an application of dispersal theory?
Vulnerability to climate change
55
How can dispersal theory be used to show impact climate change?
Sampling - current habitat Climate envelope - to show whether climate impacts location of species Climate model predicts change in climate across areas Ecologists, species disp knowledge - can predict where populations will move to
56
What is the heritability of dispersal traits vs other complex behavioural traits?
Heritability estimated from birds and insects ~0.35 Other complex behaviour traits ~0.23
57
What is a key genetic trait of complex behaviours?
Likely polygenic but genes have a large effect
58
What are examples of genes and how they have impacts on different behaviours?
For - signalling receptor - larval foraging, boldness in mice, risk taking in humans Drd4 - dopamine receptor - great tits + VNTR - serotonin receptor - monkeys and mice, aggression & dispersal Pgi - metabolic enzyme glanville fratillary
59
What are the 2 different ways a gene can impact behaviour?
Different modes of action - neurotransmitter vs metabolic enzyme
60
What are two different behaviour syndromes in Tribiolium?
Small bodysize vs large bodysize
61
What are the behaviour syndromes common in small body size tribiolium?
Small bodysize Short legs / small wings Fewer eggs High egg provisioning Short development time
62
What are the behaviour syndromes common in large body size tribiolium?
Large bodysize Long legs / big wings More eggs Less egg provisioning Long development time
63
What is the etomology of syndrome?
Greek, run together
64
How are behaviours syndromes?
Genetics of dispersal itself -> predictably associated with other traits -> syndrome
65
What is a consequence of different phenotypes?
Complex phenotypes suited to alternate life history strategies
66
What is a feedback loop for terrotrial expansion?
Individuals with genes to disperse do, so they breed with others that can spread These offspring can travel even further so have a high likelihood of breeding with other far dispersing gene organisms This cycle then perpetuates slowly increasing territorial range every generation
67
What is a case study of evolution of a feedback loop for territorial expansion?
Tribolium beetles were bred and proved that dispersion can be selected for so has a genetic trait Evolution - 0cm to 8cm over 6 generations No-evolution - 0cm to 6cm over 6 generations
68
When were cane toads introduced to queensland?
Early 20th century
69
What were the problems with cane toads in austrailia?
Cane american beetles live on ground were toads live but australia they live in top of sugar cane Toads needed shelter during day Toads decimated local fauna
70
How has dispersal changed in cane toads in australia?
Most recently colonized areas moving ~5x further than 14ya & 10x further than native range More of a pattern within sites Clear pattern of increasing tendency to move between days Rapid evolution of these 2 behaviour traits driving accelerating spread
71
What morphological changes in cane toads in native and invasion populations?
Lagrer Radioulna (forearm) Thinner pelvic girdle Both traits associated with being able to make bigger, longer hops
72
How can you study dispersal in a lab?
Tribolium live in flour + oats box give 2 hours to settle Then place plastic sheet just undersurface Pour and filter out Tribolium of top and then for bottom Then count and select 30 from each group and bred over generations and then repeat first experiment

Sem 2: Behavioural ecology (11 decks)

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