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Animal Behaviour > Avoiding Predation; Territoriality; Group-Living > Flashcards

Avoiding Predation; Territoriality; Group-Living Flashcards

1
Q

What are the predator avoiding techniques we discussed in lecture? (6 items)

A
  1. alarm calling
  2. predator distraction
  3. predator dilution
  4. Aposematism
  5. Mullerian and Batesian mimicry
  6. Camouflage
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2
Q

Name some anti-predator tactics that take advantage of the profitability equation or the rate of energy intake equation?

A

1) some animals can evolve harder shells or spiky armour to increase handling time
2) some animals can reduce body size to become harder to find - increases search time & also reduces amount of energy obtained
3) Some animals have evolved camouflage to become hard to find - increases search time

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3
Q

What is the difference between Batesian and Mullerian mimics?

A

Batesian mimics resemble unpalatable species, but are not actually unpalatable. Dishonest signal.

Mullerian mimcs resemble unpalatable species, and also are unpalatable.

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4
Q

Give an example of (a) Batesian mimicry and (b) Mullerian mimicry

A

a. ) Tephritid flies resemble jumping spiders

b. ) Heliconius butterflies all resemble one another, all unpalatable.

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5
Q

True or false. For every predatory tactic, there are tradeoffs associated with having the tactic.

A

true

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6
Q

What are some potential difficulties in evolving alarm calling or predator distraction?

How can these problems be addressed?

A

Problem:

  • This kind of tactic draws predator attention from the group to yourself
  • The predator could become less naive/more experienced and recognize purposeful distraction behaviours.

Solutions:

  • Manipulate the frequency of the alarm calls that make it harder to locate where the sound comes from
  • Alarm calls or distraction tactics may put you in danger, but ensure survival of your relatives and your genes within them.
  • Alarm calls or distraction tactics can be reciprocated by your own relatives, benefiting you later
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7
Q

What is a search image?

A

A search image is something a predator develops, where they look for specific characteristics or features in order to find camouflaged prey.

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8
Q

What are some potential difficulties in evolving camouflage as a predation evasion tactic?

How can these problems be addressed?

A

Problems:

  1. predators can develop a search image to find you quicker
  2. it may be harder for you to find mates
  3. Complex to evolve because it may involve multiple loci
  4. environments can change, making you not camouflaged anymore

Solutions:

  1. Have many polymorphic forms of the camouflage, to make it difficult for predators to form a search image
  2. Try to find mates with non-visual cues - pheromones perhaps
  3. If the loci are closely linked, camouflage may be easier to evolve due to hitchhiking
  4. Adapt to camouflage in new environments
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9
Q

Give an example of an experiment portraying development of a search image?

A

Chickens improved the ability to find camouflaged rice grains (painted to match the background) in one experiment. They had developed a search image for the camouflaged rice grains.

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10
Q

What are some potential difficulties in evolving aposematism as a predation evasion tactic?

How can these problems be addressed?

A

Problems:

  1. Predator has a learning curve - it may eat you before realizing you’re toxic
  2. Energy cost to producing the toxin
  3. coloration may evolve before toxicity, making you more easy to see and yet not being unpalatable

Solutions:

  1. Predators could teach their young to avoid you, or you could adapt to a colour that is universally recognized by predators as dangerous. Also, even if you die, your relatives, that carry your genes, would be left alone because the predator has learned to avoid your species.
  2. You could obtain the toxin through your diet, avoiding having to make the toxin yourself and waste energy doing so.
  3. poison and colouration have shown to evolve more or less simultaneously
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11
Q

What are some potential difficulties in evolving Batesian Mimicry as a predation evasion tactic?

How can these problems be addressed?

A

Problems:

  1. the species being mimicked are at a disadvantage because predators could potentially think you’re palatable because your mimics are
  2. Complex trait to be evolved, needs multiple loci to be selected for.
  3. It could confuse mates not knowing if you’re their species or the mimic species

Solutions:

  1. The mimics could be less common than the species they are mimicking. negative frequency dependent selection can prevent the mimics from becoming common (because in negative frequency dependent selection, the most common phenotype gets selected against, because the more common it gets, the more it decreases fitness). Mimics can often mimic multiple model species, preventing the model species from being at a disadvantage. There’s also the dilution effect, which means if the mimics were more common than the model species, the model species are less likely to be predated on.
  2. Loci involved could be closely-linked, which makes it easier to evolve via hitch-hiking.
  3. Evolution of different ways to attract mates - pheromones maybe
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12
Q

Give an example of a type of mimic species that mimics multiple model species

A

A type of swallowtail butterfly comes in two morphs, each morph mimicking a DIFFERENT model species.

Interestingly, these two morphs cannot interbreed, because it would result in unfavourable intermediates, ensuring only these two morphs succeed.

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13
Q

What is negative frequency dependant selection?

A

The most common phenotype becomes less fit as it becomes more common, leading to natural selection to select against that common phenotype.

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14
Q

What are some potential difficulties in evolving Mullerian Mimicry as a predation evasion tactic?

How can these problems be addressed?

A

Problems:

  1. Complex trait, needs selection to occur at multiple loci
  2. Mates might get confused what species you are
  3. Learning curve for predators to learn the mimics are unpalatable

Solutions:

  1. Loci could be closely linked, allows evolution to be easier via hitchhiking
  2. You can evolve other species-specific signalling methods to find mates - pheromones maybe
  3. positive frequency dependent selection - As the mimic phenotype becomes more common, and they are all unpalatable, the predator learns to avoid this morph. The learning curve would therefore be faster.
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15
Q

True or false. Batesian mimicry is less of a problem if mimics are in greater numbers because of (1) the negative frequency dependent selection against them and (2) the dilution effect the model (actually toxic) species take advantage of because of them

A

True

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16
Q

Predator-prey interactions often lead to the evolution of _______ adaptations, leading to an evolutionary ______ race

A

Antagonistic, arms

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17
Q

In order to increase handling time, some species of prey have evolved running adaptations. Name the three types of running adaptations discussed in class.

A
  1. the foot bone to femur length ratio gets higher. Good runners have long foot bones, similar to the length of their femur.
  2. The fibula and tibia fuse for extra support
  3. prey can evolve to run on the tips of their toes (ungulates)
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18
Q

What is the Life-Dinner principle?

A

We often see that the selective pressures on the prey are stronger than on the predators when it comes to antagonistic evolution of predator evasion tactics. For example, prey evolve running adaptations much faster than predators. This is because of the Life-Dinner principle.

Selection pressure is stronger on the prey because they have their lives on the line, but for predators they simply have dinner on the line

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19
Q

In order to increase handling time and make themselves a less profitable food item, some prey have evolved adaptations for better body armour. Can you give an example?

A

Gastropod families have seen over the years a thickness in their shells, and a narrowing of the aperatures in their shells.

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20
Q

Habitats differ in quality, and there have been two models proposed to explain what habitat types animals choose, what are the names of these models?

A
  1. ) The Ideal Free Distribution model

2. ) The Ideal Despotic Distribution model

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21
Q

Describe the Ideal Free Distribution model.

After describing it, explain what we expect in the end.

A

This model explains that animals choose habitats based on habitat value (i.e. how resource-rich the habitat is).

Individuals will first occupy habitats of the highest quality first (has most resources),

but eventually these habitats get so saturated by individuals that the habitat value becomes equivalent to other habitats that were previously thought of as lower quality.

At this point, animals begin occupying the other habitats.

In the end we should have…

  • more individuals in the initially “best” habitat
  • resource per capita/per individual should be equal across all habitats (this model forms a Nash equilibrium)
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22
Q

Describe the Ideal Free Distribution (IFD) model.

After describing it, explain what we expect in the end.

A

This model explains that animals choose habitats based on habitat value (i.e. how resource-rich the habitat is).

Individuals will first occupy habitats of the highest quality first (has most resources),

but eventually these habitats get so saturated by individuals that the habitat value becomes equivalent to other habitats that were previously thought of as lower quality.

At this point, animals begin occupying the other habitats.

In the end we should have…

  • more individuals in the initially “best” habitat
  • resource per capita/per individual should be equal across all habitats (this model forms a Nash equilibrium)
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23
Q

What are the assumptions under the IFD (ideal free distribution) model? (2 points)

A
  1. Animals must be able to recognize the value of different habitats
  2. Animals must be allowed to freely move about, and no competitor can prevent others from inhabiting the habitat.
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24
Q

Describe the Ideal Despotic Distribution (IDD) model.

After describing it, explain what we expect in the end.

A

This model like the IFD model focuses on animals choosing habitats based on quality but, here, competition plays a role of conflict.

The stronger competitors will live in the better habitat, and EXCLUDE others from that habitat.

The weaker competitors are forced to reside in the poorer quality habitat.

In the end:

  • The resource per individual is NOT equal! The individuals living in the higher quality habitat get more resources than those living in poorer quality habitats.
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25
Q

in one population of red-winged blackbirds…

There is one male who owns the biggest territory
The other males own similiar sized smaller territories

The large territory has 12 resource units (RUs)
The smaller territories have 4 resource units (RUs)

Females need at least 4 RU to produce 2 babies.
Strong female competitors would prefer 6 RU to produce 4 babies.

Describe what you would expect to see under the …

a) IFD (Ideal Free Distribution) model
b) IDD (Ideal Despotic Distribution) model

A

a)

Our end goal is to make sure all individuals have the same resource amount. Females need at least 4 RUs, so we need to make sure every bird has exactly 4 RUs.

the large territory has 12 RUs, so the number of females we can fit in is 12/4 = 3 females.

So in this scenario: 3 females in the big territory, and 1 female per small territory.

b)

Our end goal is to make sure the stronger competitors are in the larger territories. Strong female competitors require 6 RUs, so in our large territory we can have 12/6 = 2 strong female competitors.
The rest of the females are poorer competitors and will have to make do with 4 RUs, 1 female per smaller territory.

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26
Q

What is the difference between philopatry and dispersal?

A

Philopatry is when offspring remain in their place of birth.

Dispersal is when offspring do NOT remain in their place of birth, and migrate to find a new place to live.

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27
Q

Which is more common in most animal systems; dispersal or philopatry?

A

Dispersal

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28
Q

What are some costs to dispersal?

A
  • energetically expensive to disperse
  • unfamiliar environment might be poor in resources
  • may not be adapted to new environment
  • lose benefits of group-living or maternal care
  • harder to find mates
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29
Q

What are some costs to philopatry?

A
  • inbreeding
  • competition with relatives for resources
  • If the environment you were born in has many predators or many parasites, you are stuck having to deal with them.
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30
Q

What are the three hypotheses for why most animal systems prefer dispersal?

A
  1. Avoiding inbreeding
  2. Avoiding competition with relatives for RESOURCES
  3. Avoiding competition with relatives for MATES
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31
Q

For the following hypothesis for why dispersal is preferred:

“Avoiding inbreeding”

would you expect males, females or both to disperse under this hypothesis?

A

At least one sex needs to disperse, depending on whichever sex loses more from inbreeding

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32
Q

For the following hypothesis for why dispersal is preferred:

“Avoiding competition for resources”

would you expect males, females or both to disperse under this hypothesis?

A

Both males and females will need to disperse with equal probability

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33
Q

For the following hypothesis for why dispersal is preferred:

“Avoiding competition for mates”

would you expect males, females or both to disperse under this hypothesis?

A

The sex that must go through higher competition for mates must be the one dispersing. Often this is the male.

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34
Q

Define: home range

A

A home range is a general area where an individual spends most of their time. Home ranges are undefended areas.

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35
Q

Define territory

A

A territory is an area that is defended and exclusively used by an individual or group.

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36
Q

What are the two types of resources territories may have? Define them and give examples

A

Divisible resources and nondivisible resource.

divisible resource is a resource that the more you have, the more offspring you can produce..eg. food

a non-divisible resource is a resource that if you have none, you won’t reproduce…e.g. nest sites

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37
Q

If nest abundance is high, this means competition for this resource is ______(high/low), so in this scenario you would see ___________territories

A

high nest abundance = low competition

this means you’ll have contiguous (touching each other) territories.

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38
Q

What do contiguous territories look like?

A

It’s where territory boundaries are touching. Territories tend to be big and crowded.

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39
Q

If nest abundance is low, this means competition for this resource is _____(high/low), so in this scenario what kind of territory would you see? Will they be territorial?

A

Nest abundance is low = competition for this resource is HIGH

Animals won’t have territories, instead they will just be defending the nest.

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40
Q

When discussing the graphs with fitness on the y-axis and territory size on the x-axis, what kind of shape does the benefit curve have? Why?

A

It is a curve of diminishing returns.

This is because you do get access to more resources with territory size (which is the benefit) BUT you also increase the distance to bring food back to the nest with increased territory size.

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41
Q

When discussing the graphs with fitness on the y-axis and territory size on the x-axis, what kind of shape does the cost curve have? Why?

A

The cost curve is always linearly increasing. This is because with increased territory size you increase the distance to bring food back to the nest, and you also have more territory to defend, which is energetically expensive to patrol

42
Q

When discussing the graphs with fitness on the y-axis and territory size on the x-axis, what does the peak of the NET benefits curve (i.e. benefits minus cost curve) represent?

A

It represents the optimal territory size.

43
Q

If costs are greater than benefits, the net benefit curve has a __________(+/-) slope

A

negative slope

44
Q

If benefits are greater than costs, the net benefit curve has a __________(+/-) slope

A

positive slope

45
Q

True or false. When discussing the graphs with fitness on the y-axis and territory size on the x-axis, the point at which the benefit curve begins to go up for the first time is the territory size at which the first nest is found.

A

True. This is very important concept to know, see page 29 of notes if this is unclear.

46
Q

When discussing the graphs with fitness on the y-axis and territory size on the x-axis, how do we know if we have a scenario where the animals would choose to have contiguous/touching territories?

A

The point at which the NET benefits curve peaks is not where the benefit curve peaks.

If the net benefit curve peaks after where the benefit curve peaks, this means the territory size can be bigger than just protecting one nest.

47
Q

When discussing the graphs with fitness on the y-axis and territory size on the x-axis, how do we know if we have a scenario where the animals would choose to not be territorial but rather just defend the first nest they encounter?

A

If the point at which the NET benefits curve peaks at where the benefit curve peaks.

This means the optimal territory size is where the first nest is encountered.

48
Q

True or false. Habitats with high competition tend to not be territorial, but rather protecting the first nest encountered.

A

true

49
Q

What is density-dependent reproduction? (from the paper)

A

Density-dependant reproduction is a negative correlation between number of offspring produced and density of the population

50
Q

A population that shows density-dependent reproduction has what kind of territoriality if any?

A

Contiguous territories

51
Q

A population that does NOT show density-dependent reproduction has what kind of territoriality, if any?

A

None. They would just be defending area around nest.

52
Q

True or false. Some components of fitness increase with group size, some components of fitness decrease with group size, and some components of fitness are not affected by group size

A

True.

53
Q

What would the shape of a function with fitness on the y-axis and GROUP SIZE on the x-axis look like? Why?

Where would the optimal group size be on this kind of graph?

A

It would be hump-shaped (like a normal distribution).

This is because group living comes with benefits (going up the hump) but also comes with costs if there’s too many group members (down the hump).

The optimal group size is the very top of this hump, it’s where fitness is maximized.

54
Q

There are many benefits to group living. Name the two benefits for FORAGING in groups, and explain why it is a benefit.

A
  1. Group hunting - hunting in groups is beneficial because you can catch bigger prey or prey that is too difficult to capture alone.
  2. Information exchange - if members actively/passively relaying information on where you can find food, it makes finding food easier.
55
Q

Give some examples of group hunting.

A

E.g. lions work together to take down larger prey like buffalo.

E.g. dolphins work together to herd fish on to the edge of the bank, then they push themselves on to the bank, pushing the fish with them, and this allows them to capture fish, it also helps seagulls get some fish too, so they follow where the dolphins go too.

E.g. Harris hawks hunt together to get more difficult to capture prey, some members chase out the prey from between thorny shrubbery, while others keep sight of where the prey is and capture it.

56
Q

True or false. The goal of information exchange is to benefit other group members, either passively or actively

A

True

57
Q

True or false. Animals that often obtain resources from resources that are clumped and unpredictable are the ones that benefit most from information exchange

A

True

58
Q

What is local enhancement, and how does that differ from information exchange?

Also, give an example of local enhancement

A

In local enhancement, individuals accidentally leave cues to the location of food resources that others may use. The difference with information exchange is that in local enhancement, there is no intention of benefitting others, it happens accidentally.

For example, vultures often fly around carcasses, which other scavengers use to locate the carcasses. It’s accidental

59
Q

Give examples of information exchange

A

Fishing osprey carry their fish in their talons in such a way to showcase to other members the quality of the fish they found. If the fish is a good sought-after resource (a huge fish), the others will fly in the direction that osprey came from.

Honeybees do a waggle dance to inform other members the location of a good quality flower patch

Guanay cormorants form rafts, lining up while floating on the water, pointing in the direction of food (fish schools). This compass is used by other members who haven’t gone foraging yet to find food

Naked mole rat species that are eusocial generally live in regions where resources are clumped and hard to find. This is because living in groups makes it quicker for at least one member to find food, and inform the others.

60
Q

There are many benefits to group living. Name the five benefits for PREDATOR AVOIDANCE in groups, and explain why it is a benefit.

A
  1. Predator dilution - you’re less likely to be the one predated on if you’re in a larger group
  2. Predator confusion - Certain morphological traits or behaviours from group members confuse predators, making predation less likely to be successful
  3. Alarm call - Individuals can give alarm calls to warn members of a threat
  4. Vigilance - You are safer from predation because some individuals of the group keep watch out for predators, this means you don’t have to be vigilant all the time and allows you to focus energy on other stuff.
  5. Group defense e.g. mobbing - Being in a group protects you from predators because the group members form a defense system
61
Q

Give examples of predator dilution

A

Giant Mayflies emerge at the same time to overwhelm their predators and make sure at least some of them survive

13-year cicadas emerge every 13 years, in great numbers

62
Q

Give examples of predator confusion

A

Sardines swim in schools and form shapes to confuse dolphins.

Zebra stripes may be so to confuse predators and prevent them from singling out certain individuals

63
Q

Give examples of group defense

A

Fieldfares mob ravens

Water buffalo adults surround the cubs and form a defense circle against lions.

64
Q

There are many benefits to group living. Name the two benefits for COMPETITION in groups, and explain why it is a benefit.

Give an example for each.

A
  1. interspecific competition - being in groups gives benefits over other species.
    e. g. fish that are in schools can overwhelm territorial solitary fish to gain access to whatever resource they’re protecting
  2. Intraspecific competition - being in groups may benefit you in competition with members of your own species.
    e. g. lions that are looking for a new pride may form coalitions to displace the males from small prides
    e. g. queen ants may aggregate with other queens to outcompete queens that are looking for territory by themselves.
65
Q

There are many benefits to group living. Name the one benefit for FINDING MATES in groups, and explain why it is a benefit.

A
  1. Leks and choruses - in groups, you can form leks, which draw in females, or do choruses, which also draw in females.
66
Q

What are leks?

A

Regions where males temporarily aggregate to display themselves and compete with other males for the females.

67
Q

What are choruses?

A

Choruses are songs or sounds produced by a group of males to attract females to an area, like frog croaks.

68
Q

Why are females more likely to be attracted to associations of males (leks and choruses) rather than to individual males?

A

Because it gives females the option of choice.

69
Q

There are many benefits to group living. Name the one benefit for CARING FOR OFFSPRING in groups, and explain why it is a benefit.

A

Alloparental care - it increases the survival chances of the offspring.

70
Q

Define “plural breeding”

A

Plural breeding is when all the females breed at the same time, and so all the females cooperate in nursing all the cubs, even the ones they aren’t the mother to

71
Q

Define “Helpers” in the context of parental care. Give examples of helpers

A

Helpers are individuals, often older offspring of the breeding pair, that help with parental care of their younger siblings. In doing so, these helpers often delay their own reproduction.

e. g. black-backed jackals show that pup survival increases as the number of helpers in the group increases.
e. g. meerkat pups’ average daily weight gain is higher with increases in the number of helpers per meerkat pup.

72
Q

True or false. In eusocial animals, there are members that are often PERMANENTLY non-reproductive. Give examples if true.

A

True.

Eusocial hymenoptera like bees and ants, termites and naked mole rats have workers that never reproduce.

73
Q

True or false. Recall that the fitness function in terms of group-living is a curve that is hump-shaped. But, that curve can start off at different places depending on the species. If that curve begins at a fitness below 1, these species are never okay with being solitary (solitary living is unsustainable = they will go extinct). If the curve begins at a fitness above or equal to 1, they can handle being solitary

A

True

74
Q

All social spiders are found in the _______

A

tropics

75
Q

True or false. Out of the 20 species of social spiders, 18 have evolved cooperative social behaviour independently/convergently

A

True

76
Q

Some spider genera are sub-social. What does that mean?

A

They remain with the mother as spiderlings, but disperse as adults away from the nest, to find non-relative mates.

77
Q

What intrinsic feature in social spiders made it beneficial to be social/live in groups?

A

The ability to build dense 3D webs. Alone, spiders must waste a ton of energy creating silk for these dense webs, but together they waste less energy, and as a benefit, these webs give them better protection from predators and the elements, like rain.

78
Q

Dense 3D webs are good protection against ________ and ______

A

predators and rain

79
Q

True or false. Because social spider webs are 3D structures, they will be subject to scaling laws of 3D objects, like the SA:V ratio effect on 3D structures.

A

True

80
Q

Social spiders are only present in _____ elevations in equatorial (low) latitudes. In contrast, sub-social spiders are found everywhere except in these regions.

A

low elevations/low-land tropics

81
Q

Are social spiders found in higher elevations?

A

No

82
Q

Are sub-social spiders found in lower elevations/low-land tropical rainforests?

A

No

83
Q

In the tropics, rain intensity is highest at _______(low/high) elevations

A

Intensity is highest at low elevations

84
Q

In the tropics, predation rate is highest at _______(low/high) elevations

A

Predation rate is higher at low elevations

85
Q

What hypothesis discussed in class was used to explain why sub-social spiders do not occur in lowland tropical rainforests / low elevations?

A

The predation-precipitation hypothesis

86
Q

Describe the predation-precipitation hypothesis

A

According to this hypothesis, sub-social spiders do not occur in lowland rainforests because these areas have…

  1. Very high rain intensity, and sub-social spiders do not build webs that can withstand the constant force
  2. Very high predation rates, and so if the mother of the sub-social spiderlings is eaten, the spiderlings cannot rely on others to care for them.
87
Q

Leticia and her team took sub-social spider nests and transplanted them in a lowland tropical rainforest. Some of these nests were protected from predators, some from rain, some from both, and some were left unprotected. All this was also done in an intermediate elevation. What were the results from this experiment?

A

Nests that were protected lived longer than unprotected nests in the low elevation site. But protection against elements or predation didn’t really have an effect on nests in the intermediate elevation site. This showed that in intermediate sites, rain and predation isn’t an issue for sub-social spiders, but it becomes an issue in lower elevations.

88
Q

Can SOCIAL spiders live in smaller groups or by themselves? A study in Ecuador artificially created nests with smaller group sizes. They used their data to create a fitness x group size curve. What did they find out?

A

Social spiders cannot live in small groups or alone. The fitness of the curve at the beginning is below 1, meaning it is unfeasible for them to live alone or in small numbers.

89
Q

What hypothesis was rejected for explaining why SOCIAL spiders do not occur in HIGH elevation forests?

A

The prey-abundance hypothesis was rejected. They originally though maybe there wasn’t enough food to sustain a large colony, but research found that insect biomass was actually higher in some highland rainforests than in lowland rainforests.

90
Q

Insect SIZE is __________(greater/lesser) in lowland rainforests compared to highland rainforests

A

greater in lowland rainforests

91
Q

What hypothesis in class explains why SOCIAL spiders are not found in highland rainforests/high elevations?

A

The prey-size hypothesis

92
Q

Describe the prey-size hypothesis and how it serves to explain why social Anelosimus spiders do not appear in highland rainforests

A

According to this hypothesis, social spiders catch fewer insects because their large nests have a small SA:V ratio (less SA available to catch insects).

However, living in a place like the lowlands helps because they have an increased chance of catching a larger prey, plus cooperative hunting helps ensure they succeed at catching that prey.

In highland rainforests, social spiders cannot offset their low SAs on their webs by catching larger insects, because the insects are smaller in highland rainforests.

93
Q

Why is the “fitness x group size” function curve for social spiders hump shaped?

A

Social spiders have optimal group size at intermediate levels, so the curve is hump-shaped.

This is because there are benefits to being in a group (cooperative care, hunting, nest maintenance etc). but after some point, the web keeps getting a smaller SA:V ratio, but the insect sizes aren’t getting any bigger, so fitness drops at these group sizes.

94
Q

Is the “fitness x group size” function curve in sub-social spiders also hump shaped? Why or why not?

A

No, for sub-social spiders, fitness linearly decreases with group size. This is because with increased group size you get webs with smaller SA:V ratio, but insect sizes are too small to maintain those group sizes in highland elevations.

95
Q

Recall that for many species, the fitness x group size curve is hump-shaped. The peak of this curve is the _________ group size, where fitness is maximized. However, for some groups, the group size exceeds this and reaches again where fitness = 1, at the ______ group size

A

Optimal group size

Stable group size

96
Q

What is the “minimum group size”?

A

This is the group size at which the fitness is = 1 for the first time. Group sizes smaller than this point will go extinct

97
Q

There are two types of groups. Non-kin and kin groups. What is the difference?

A

Non-kin groups are composed of individuals that are NOT relatives.

Kin groups are composed of individuals that are relatives.

98
Q

In a non-kin group, if the group had free-entry of individuals, the group size would be equilibrated at the ______ group size.

A

stable group size

99
Q

In a non-kin group, if the group had controlled-entry of individuals, the group size would be equilibrated at the _____ group size.

A

optimal group size

100
Q

In a kin group, if the group had free-entry of individuals, the group size would equilibrate at what group size?

A

It would be less than the stable group size. This is because the individuals joining the group would recognize that they are harming the group fitness, and will act altruistically

101
Q

In a kin group, if the group had controlled-entry of individuals, the group size would equilibrate at what group size?

A

The group size would be held at a size that is larger than the optimal group size that can go all the way to stable group size.

This is because the group will act altruistically to allow relatives to join because they will be compensated for helping relatives.

Animal Behaviour (5 decks)

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