BIOL 354 > Lecture 5 (after midterm) > Flashcards

Lecture 5 (after midterm) Flashcards

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1
Q

What are niche requirements?

A

availability of types of resources and types of shelters

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2
Q

What is a study conducted by Jean-Guy J. Godin on diet overlap and similarity in microhabitat use (experiment and results)?

A
  • Experiment: looked at territory radius (cm) territory vs similarity of microhabitat use and radius (cm) territory vs diet overlap (%)
  • Results: Increase overlap of niche in diet: size of optimal area to defend increases bc it’s optimal to monopolize resources from competitors
  • Results: Decrease in overlap of microhabitat: don’t need to defend a large habitat
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3
Q

How does Jean-Guy J. Godin’s experiment looking at territory size and niche overlap and microhabitat use relate to Brown’s model of economic defendability?

A
  • aP: Productivity gain (growth potential) if not defending
  • bP: Productivity gain if defending
    -> If bP is greater than aP than individuals will defend
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4
Q

What is the operational sex ratio?

A

Operational sex ratio: Within a habitat there will be a number of mating females and a number of mating males

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5
Q

What impact does operational sex ratio have?

A

Operational sex ratio has huge impacts on mating competition, mating tactics, etc.
-> So competition will be shaped by # of mating females and number of mating males (operational sex ratio)

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6
Q

What is the formula for Operational sex ratio of CRR?

A

of potentially mating males / # of fertilizable female

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7
Q

How was the competitive resource ratio invented?

A

People asks themselves if the operational sex ratio could be applied to competitive interactions outside of mating contexts -> it could!

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8
Q

Can the Operational Sex Ratio be generalized to any consumer-resource system?

A

Yes because food and mates are analogous to consumable resources that are competed for

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9
Q

What is the difference between the competitive resource ratio and the Optimal foraging theory (OFT)?

A

The CRR looks at what happens if we shift the operational sex ratio -> do we expect an increase or decrease in competition/aggression. The absolute amount doesn’t matter because we aren’t predicting the exact level of aggression, we’re predicting a trend

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10
Q

What was the 1st experiment and results by Grant et al. 2000 on CRR?

A

1) Experiment 1: Manipulated # of potential mates
2) Results 1: when you have more females than males, a low CRR, that level of aggression is low. But as we increase the # of males or decrease the number of females, higher CRR, get an increase in the level of aggression. If we increase the CRR more, aggression tails off a bit around CRR = 2

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11
Q

What was the 2nd experiment and results by Grant et al. 2000 on CRR?

A

1) Repeated experiment with same pop 2: but manipulate amount of food by pipetting the amount of food
2) Results 2; Increase # of competitors for limiting food or decrease food with same amount of competitors: get increase in CRR than it tails off at a CRR of 4: it’s not statistically different from the CRR = 2

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12
Q

What was the 3rd experiment and results by Grant et al. 2000 on CRR?

A

1) Repeated experiment 3: start at CRR of 2 and ramp it up to 8 (potentially ecological irrelevant)
2) Results 3: aggression decreases continuously

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13
Q

What do the combined data sets of the 3 experiments in Grant et al. 2000’s paper on CRR demonstrate?

A

Gave a parabolic curve which peaks for both food and mates at a CRR of 2. So the ratio of resources to competitors is more important than what they’re competing for

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14
Q

Why if there’s an increase in CRR there’s more aggression? (Grant et al. 2000’s paper on CRR)

A

Increasing aggression with increase in CRR bc there are more competitors so the competitors will get aggressive in order to increase the amount of resource they get, to monopolize it.

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15
Q

Why does aggression drop as CRR increases past CRR of 2 demonstrated in Grant et al. 2000’s paper on CRR?

A

It’s no longer profitable -> bP - T still increases, but disproportionately.

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16
Q

What does CRR allow us to do?

A

Competitive resource ratio allows us to compare competition across different resource types and look at trends in competition within different populations and different microhabitats

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17
Q

Is CRR density dependent?

A

Yes and no, actual aggression responses are density dependent, but not the trends

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18
Q

What is Noel et al. 2005’s experiment on CRR?

A

Put 10 juvenile cichlids in a tank with 1 patch of food. 10 fish for 2 patches of food. 10 fish for 5 patches of food and then 10 fish for 10 patches of food. Amount of food not changed, just how it was spread across the tank. Look at aggression in chases per minute

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19
Q

What is the model used in Noel et al. 2005’s experiment on CRR?

A

Ideal free distribution

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20
Q

What were Noel et al. 2005’s results from the experiment on CRR?

A
  • Results: chasing (aggression) increases with increase in CRR to about 2 and then it drops after this.
  • Look at CV of body mass; Results:
    1) When CRR is low: there’s low variance in CV
    2) When CRR is high: there’s low variance in CV
    3) CRR around 2: increase in CV variance within the group
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21
Q

What is CV?

A

a common measure of body mass index (BMI) variability

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22
Q

In Noel et al. 2005’s paper on CRR, why is there an increase in CV variance at a CRR of around 2?

A

Because some individuals were able to compete better and increased in size, and those that couldn’t compete as well, decreased in size.

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23
Q

What was the issue with Noel et al. 2005’s experiment?

A

There’s a fair bit of initial variance in mass amongst the juvenile cichlids to begin this so it could have influenced results

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24
Q

What was the experiment in Kim et al. 2004’s paper?

A

Manipulated CRR in a small patch vs a larger patch and then looked at variance in mass (CV)

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25
What were the results in Kim et al. 2004's paper?
Larger patch had more individuals that could reach the patch so less aggressive, but smaller patch didn’t have as many individuals that could reach the food so aggression increased
26
After running the experiment for 10 days in Kim et al. 2004's paper, what happened to CV in small defendable patches and what happened in large undefendable patches?
1) Small defendable patch: had higher levels of aggression, fewer individs getting to patch leading to increase in coefficient of variation 2) Large undefendable patch: lower aggression, higher access, and reduced coefficient of variation
27
In Kim et al. 2004, what occurred at low, high, and intermediate CRR?
1) Low CRR: proportion of resources is high bc they aren’t going for the resources -> more or less similar access so CV is low since they grow about the same and aggression is low 2) High CRR: proportion of resources is high bc they aren’t competing for resources -> CV is low since they grow about the same and aggression is low 3) Intermediate CRR: proportion of resources is low due to monopolization of the resource since some will do well and others won’t do as well. (competitive exclusion). Therefore, CV is high since there’s more variation and there's more aggression
28
What was the experiment and question looking at predation pressure and CRR (repeated experiment from Kim et al. 2004's paper)?
- Exposes Japanese medaka to low risk and high risk with repeated experiment from Kim et al. 2004's paper. - Competing for food in a safe environment vs competing for food in a risky environment: does it change pop level consequences and defendability of the patch?
29
What were the results without risk for the experiment looking at predation pressure and CRR (repeated experiment from Kim et al. 2004's paper)?
1) Small patch: fewer foragers, high aggression 2) Larger patch: more foragers, low aggression
30
What were the results with increased risks for the experiment looking at predation pressure and CRR (repeated experiment from Kim et al. 2004's paper)?
1) Large undefendable patch: reduction in # of foragers 2) Small defendable patch: increase in # of foragers and level of aggression falls
31
Why would predation risk decrease foragers on large patch?
Higher costs decrease foragers on large patch due to increased risk involving defending a large patch, making them more risk-averse
32
Why increase in # of foragers on a small patch when exposed to risk?
More access bc competition is decreasing bc there's more variation in the # of individuals at the patch since individuals won’t defend all day long, instead they scramble, compete and hide
33
What effect does an increase in # of foragers on the small have on CV at low risk vs high risk?
1) Low risk: low CVs 2) High risk: increase in variation of CV bc some are risk-averse while others take risks and will benefit by increasing in weight
34
What was the 1st experiment in Chuard et al. 2016's paper on CRR; competition for multiple resources?
Adult sex ratio (CRR) in guppies, looking at 2 males to 4 females, 3 males and 3 females, 4 females to 2 males, and 5 females to 1 male. LA = lower Aripo (high risk) and UA = upper Aripo (low risk)
35
What were the results in Chuard et al. 2016's paper on CRR for the first experiment; competition for multiple resources?
Results (low predation pressure): 1) Males: with less females, there’s higher aggression 2) Females: as you shift to female bias, females become extremely aggressive
36
What are males and females competing for in Chuard et al. 2016's paper?
Could be competing for mates or for food
37
How does Chuard et al. 2016's paper address the question on what resources female and male guppies are competing for?
- Experiment: Fish in a tank overnight and watch. If we take extreme ratios of 5 males to 1 female or 5 females to 1 male, what happens? - Results: Before female is added and after female is added = aggression levels remain relatively the same suggesting that they’re competing for multiple things at the same time. Same trend seen before males are added and after males are added in female bias shoals.
38
Why would you expect these aggression affects to be greater in lower predation pop than higher predation pop (Chuard et al. 2016)?
Magnitude of aggression is greater in lower predation populations because in lower predation populations they’re competing for both mates and food, but in higher predation populations the cost of competing are increased so they focus more on survival
39
In Chuard at al 2022's paper what was the experiment?
Go to pops close to even and female bias, or close to even and male bias pops (fully natural population)
40
In Chuard at al 2022's paper what were the results to the experiment?
1) Male-biased Shoals: The intrasexual aggression rate in males increases as the ASR increases (meaning more males relative to females). This increase is likely due to the heightened competition among males to secure access to the fewer available females. The intrasexual aggression rate in females decreases as the ASR increases 2) Female-biased Shoals: Female intrasexual aggression rate increases as the ASR decreases (or becomes more female-biased). Conversely, the male intrasexual aggression rate decreases as the ASR decreases (meaning fewer males relative to females)
41
What is the dear enemy or friendly effect?
Level of aggression is high when territories are formed is very high, but overtime (days), the level of aggression decreases as they become familiar with each other’s smell, call, etc, so levels of aggression decrease because they save energy.
42
How is energy saved via the dear enemy or friendly neighbour effect?
Many territorial species can reduce costs of defence by defending near ‘familiar’ neighbours. Can rely on ‘passive’ vs ‘overtly aggressive’ territorial defence behaviour
43
What is an example of the dear enemy effect seen in song birds?
- Experiment: Goes to song bird territories and tracks aggression overtime and then goes down road and records songs of another conspecific. Traps the bird from initial territory and plays the stranger's conspecific call. - Results: the frequency of agonistic interaction increases (aggression increases)
44
What effect does the dear enemy effect have on androgen levels in cichlid fish?
- 2 familiar individuals: low levels of aggression. With the addition of novel individual (stranger) there’s an increase in aggression that decreases overtime. - This is because on the first day of adding a novel neighbour, the level of androgens of the territory holders jumps up. When you resample after a number of days, most androgen levels decrease
45
In the cricket experiment, what are the results when you pair a loser cricket with a naive cricket?
naive cricket wins bc the individual cricket that lost has an altered perceived risk
46
In the experiment when a large loser is paired with a small naive intruder cricket, what are the results?
Small naïve intruder wins
47
What is RHP what is an example of this?
Individual's 'motivation' to persist in a competitive interaction -> example includes cricket experiments
48
What do the results of the cricket experiments demonstrate (3 things)?
1) Outcome of encounter is dependent on size AND previous experience 2) Territory holders (winners) are more likely to be aggressive 3) Aggression is linked to experience, not size!
49
What alters behaviour, independent of resource Holding Potential (RHP)?
Experience (previous wins/losses) can modify behaviour independent of RHP
50
Who came up with Individual trade-off based on Resource holding potential (RHP)?
Parker, 1974; Ydenberg & Dill, 1990
51
What is the formula for RHP?
V(RHP) = Ve^(bP-T)
52
According to the RHP, individual’s decision based on current condition(s) / constraint(s), what are 5 examples of this in regards to Jerram Brown's economic model of defendability?
1) Predation (+T) 2) Parasite (+bP) 3) Recent experience (-T) 4) Knowledge of habitat (-T): reduces the costs 5) Prior residency effects (-T and +bP): reduces costs and familiarity allows individuals to know where resources are
53
What is the perception of value of bP-T dependent on (productivity gained if defending - added cost of territorial defence)?
Perception of value of bP - T is dependent on past experience - Lost before: lower perceived payoff to continue competitive aggression - Won before: higher perceived payoff to continue competitive aggression
54
What is an example of the dear enemy effect where competition trade-offs are dependent upon frequency dependence and density dependence?
Hawk and dove model
55
Why is the hawk and dove model frequency dependent?
1) As the proportion of doves increases, the fitness of being a hawk increases 2) As the proportion of hawks increases, the fitness of being a hawk decreases because pay-off decreases. Meanwhile, the fitness of dove proportionally increases
56
What is a hawk in the hawk dove model?
Aggressive individual
57
What is a dove in the hawk dove model?
Not aggressive individual
58
How are resources split when a hawk goes against another hawk?
initiator gets value of (resource - cost of defending) / 2
59
How are resources split when a dove goes against another dove?
Not aggressively competing, they’re engaging in scramble competition so they split the resources
60
How are resources split when a dove goes against a hawk?
hawk aggressively takes and Dove backs off -> similar to risk-averse tactic. Some hawk gets benefits of resources and Dove backing off reduces costs
61
When does ESS occur in the hawk-dove model?
Evolutionary stable strategy: When proportion of doves and hawks is the same.
62
How are multiple foraging tactics maintained in the hawk-dove model?
The fitness associated with one is dependent on the relative abundance of the other phenotype which maintains multiple foraging tactics
63
What is a producer in a producer-scrounger model?
Producer: is the bird that finds a patch of food
64
What is the pay-off of a producer?
Payoff = E/T x exponent of rate in which the encounter the patches - energy lost to scrounger
65
What is a scrounger?
follows producers
66
What is the payoff of a scrounger?
E/T x # of producers
67
What occurs to scroungers as # of producers increases?
Pay-off increases
68
What occurs to producers as # of scroungers decreases?
Producers do better
69
What is the formula for individual trade-off based on Resource Holding Potential by Parker, 1974; Ydenberg & Dill, 1990?
V(RHP) = Voe^(bP-T)
70
What does the resource holding potential formula say about individual's decisions?
Individual’s decision based on current condition(s)/constraint(s): 1) Predation (+T) 2) Parasite (+bP) 3) Recent experience (-T) 4) Knowledge of habitat (-T): reduces the costs 5) Prior residency effects (-T and +bP): reduces costs and familiarity allows individuals to know where resources are --> Perception of value of bP - T is dependent on past experience
BIOL 354
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