Animal Behaviour-Territoriality and aggression

Question 1

What is the difference between a home range and a territory?

Answer 1

Home range is simply the area you find an animal wandering whereas territory requires defence and patrolling and gives access of an animal or a group of animals to food, mates, nesting sites, cover etc

Question 2

What was found from the experiment using blockhead fish?

Answer 2

That landmarks (stones in this case) were used to distinguish between territories and that without the landmarks, there was more aggression (fighting) between the animals

Question 3

Economic defendability graphs (those which show benefits v costs of denfending a particular site) describe/look like what?

Answer 3

Graphs show a line for the benefits of a rich area, a line for benefits of poor areas and a line for the costs to the animal. With this, we can see where the greatest difference between cost and benefit is and therefore the most beneficial area/ lowest cost for highest benefit is

Question 4

What did the study on golden-winged sunbirds (feed on nectar) show about defence of territories and the benefits of this?

Answer 4

Showed that birds that defend certain areas/flowers in times of low nectar gain more from the extra time they don’t spend foraging. But if nectar levels are high, the limiting factor is how many flowers it can get to and so it is more beneficial to go find many flowers to feed on rather than defend some against nectar-theives

Question 5

What is the trade-off for the sunbirds?

Answer 5

The nectar availability, how much the bird can get and how much defending of the territory is required

Question 6

What did the study on pied wagtails show?

Answer 6

If one bird patrols the territory, it may take them (for example) 40 minutes to complete its patrolling. However, sharing their territory with another bird means each bird would complete it in 20 mins- sharing territories with unrelated individuals

Question 7

What does the sharing of territories depend on?

Answer 7

The renewing of food in the area. The higher the rate of renewal, the more likely they are to share the territory as this minimises competition and can sustain both the individuals

Question 8

What is Resource Holding Potential (RHP)?

Answer 8

The ability of an animal to win a fight

Question 9

What are the factors that influence Resource Holding Potential?

Answer 9

Body size, residency, resource valuation, motivation, energy reserves, prior experience

Question 10

What is an Evolutionarily Stable Strategy? (Introduced by John Maynard Smith)

Answer 10

An evolutionarily stable strategy (ESS) is a strategy which, if adopted by a population in a given environment, cannot be invaded by any alternative strategy that is initially rare. This theory however does not deal with any huge external change that may bring difference selection forces into play

Question 11

Describe the Evolutionarily Stable Strategy(ESS) model using I and J as a strategy and E as the final pay off. How would you work out if an animal had an ESS?

Answer 11

The model is as follows:

For a strategy to be considered an ESS:
E(I,I) > E(J,I), or
E(I,I) = E(J,I) but E(I,J) > E(J,J)
So basically I attacking J will win

Extra: The first condition is sometimes called a strict Nash equilibrium.[9] The second is sometimes called “Maynard Smith’s second condition”

Question 12

Give an example of a mixed strategy area? (no single strategy beats another one, no ESS)

Answer 12

Side-blotched lizards have three different appearances; orange, aggressive,defend many females
Blue, mildly aggressive, defend single female
Yellow, look like females so sneak matings

None of these strategies can invade completely another so this area is known as mixed strategy

Question 13

What is Sequential Assessment?

Answer 13

It is a process by which two animals display increasingly aggressive behaviour to show their strength. If one decides it is not worth it, then they retreat otherwise the behaviour becomes more and more dangerous. This means more similar animals go on for longer

Question 14

Give an example of an animal which carries out Sequential Assessment Game? What benefits and costs are involved?

Answer 14

Red Deer:

Benefits: Females
Costs: 20-30% stags permanently damaged

1) Roars (signals body condition+size)
2) Parallel walk (closer assessment)
3) Interlock antlers (rare)

Question 15

Give another example of an animal which carries out Sequential Assessment Game and their behaviours during this.

Answer 15

Cichlids (fish)

1) Lateral orientation (like parallel walking)
2) Tail Beating
3) Frontal orientation
4) Biting
5) Mouth Wrestling
6) Loser gives up

Question 16

What does the length of fight depend on in Cichlid fish?

Answer 16

Weight asymmetry. The bigger the difference between the fish, the shorter the time of the sequential assessment/fight

Question 17

What does the study on the Speckled Woof Butterfly prove about residency and how it affects defence of a territory?

Answer 17

Proves that the owner of the territory always wins. The original owner won and then when it was removed and the invader settled, the original owner came back and was defeated by the new owner (so suggests it’s not to do with body condition/size etc, just whoever was there first)

Question 18

What does the study with Red spotted newts show about resource valuation?

Answer 18

The more valuable a resource is, the more you’re going to risk/fight to keep it. E.g the male newts fight longer for females that can lay more eggs

Question 19

What does the study with jumping spiders prove about prior experience and the effect it has on the next fight?

Answer 19

The length of the next fight after a previous one is important! If a winner fights again in the next hour, it is likely to win and if a loser fights within an hour it is likely to lose BUT over time, this evens out. After 24 hours, there is no significant difference in the outcome of the fight between those who won or lost their last fight

Question 20

Explain what is meant by ‘The War of Attrition’ (WoA).

Answer 20

Basically, whoever can wait the longest/bare the highest costs wins. There is no assessment of eachother. As duration increases so does cost but payoffs remain constant (don’t get more the longer you wait)

Question 21

Give an example of an animal which displays the War of Attrition strategy.

Answer 21

Yellow Dung Flies (males) wait on cowpats as this is where females mate with them and lay their eggs. The longer you wait on a pile of dung, the more likely you are to get to mate as other males will have moved onto another pile

Question 22

What is the main difference between winner size affecting contest duration time between the WoA model and the SAG (sequential assessment) model?

Answer 22

In WoA: The bigger the winner, the longer the duration of the contest
In SAG: The bigger the winner, the shorter the duration s

Question 23

What is the ‘Cumulative Assessment Model’?

Answer 23

Different individuals have different thresholds of when they will flee (after enduring certain amounts of costs). This model states that repeated actions prove stamina rather than are for the accurate assessment of the competitior as in SAG

Question 24

How do hermit crabs exhibit actions that link to the cumulative assessment model as oppose to SAG?

Answer 24

Hermit crabs rap on the other’s shell. This proves their stamina rather than anything else and can result in eviction of the defennder or the attacker simply leaving the other shell