Territoriality and Aggression

Question 1

What is a territory?

Answer 1

An area defended to obtain exclusive access to the resources (food, mates, etc) it contains

Question 2

What is a home range?

Answer 2

Areas of repeated use that are defended from conspecifics

Question 3

How do animals defend their territories?

Answer 3

1) Displays
2) Visual Marking
3) Olfactory Marking
4) Patrolling

Question 4

True or False: Territoriality can not put an upper limit on density.

Answer 4

FALSE - Territoriality can put an upper limit on density

Question 5

Individuals without territories may act as _________________.

Answer 5

Floaters

Question 6

What do floaters do?

Answer 6

Floaters “hang out” and try to secure extra-pair copulations or wait for the territory to become empty. They will be more peripheral, be in lower-quality habitats, etc.

Question 7

What is the Dear Enemy Effect?

Answer 7

Territorial interactions being more intense with strangers than with neighbors.

Question 8

The Dear Enemy Effect is a form of __________________ learning.

Answer 8

Habituation

Question 9

What are the possible benefits of territoriality?

Answer 9

Able to monopolize the resources contained on your territory (exclusive access to food, mates, breeding sites, etc)

Question 10

What are the possible costs of territoriality?

Answer 10

Takes LOTS of energy AND takes time away from foraging. High energy costs may limit the ability of individuals to be territorial.

Question 11

Territories need to be ________________ defendable.

Answer 11

economically

Question 12

True or False: The benefits of defending a territory have to be less than the costs

Answer 12

FALSE - The benefits of defending a territory have to be GREATER than the costs

Question 13

When is it worthwhile to defend a territory? In other words, when are the benefits greater than the costs?

Answer 13

Benefits of territoriality outweigh costs when:
1) Resources are not scarce - if flowers are abundant, no need to defend any

Question 14

What affects territory size?

Answer 14

1) Larger territories will have more resources but also be more costly to defend
2) Increasing benefits (density of resources) decreases territory size

Question 15

What happens if the territory costs more to defend (higher cost)?

Answer 15

Higher costs of defense (increased competition/conspecific density) will decrease territory size - The more energy you have to spend/the more fighting to defend your territory will cause an increase in cost and, therefore, change the ratio of benefits vs cost. In this case, it’d be optimal to defend a smaller territory.

Question 16

What is the “Hawk-Dove” game?

Answer 16

Two types of strategies fighting over a resource with value
- Hawk strategies
- Dove strategies

Question 17

What is the hawk’s strategy?

Answer 17

Hawk individuals will always escalate a fight until victory or injury

Question 18

What is the dove’s strategy?

Answer 18

Dove individuals will perform a display (still compete) but will not escalate fights

Question 19

Agonistic behavior begins with _____________ and then may escalate.

Answer 19

Assessment/display

Question 20

In the Hawk-Dove payoff matrix, what do we assume?

Answer 20

We assume equal competitors

Question 21

Are hawks or doves an ESS?

Answer 21

1) Hawks may be an ESS - depends on the value of B and C
2) Doves are NEVER an ESS

Question 22

What are conditional strategies?

Answer 22

An individual may benefit from varying their strategy depending on their opponent

Question 23

What’s another possible strategy in the hawk-dove game?

Answer 23

Bourgeois!
- Play hawk when you are the resident
- Play dove when you are the intruder

Question 24

Bourgeois strategy results in the…

Answer 24

Resident effect!

Question 25

What is the resident effect?

Answer 25

If individuals are all playing the Bourgeois strategy, the owner of the territory should always win interactions because they would act more "hawk-like," while intruders are acting more "dove-like."

Question 26

Aggression is modulated by ________________ in some invertebrates.

Answer 26

Neurotransmitters

Question 27

Aggression is primarily modulated by _____________ in vertebrates.

Answer 27

Testosterone

Question 28

High testosterone results in...

Answer 28

1) Increased aggression 2) Increased courtship 3) Increased energy cost 4) Decreased immune function 5) Decreased parental behavior - BUT... the relationship between testosterone and aggression is not strictly causative. For instance, a behavior will start before the testosterone increases. So, it can’t be why it’s driving aggressive behavior.

Question 29

The relationship between testosterone and aggression is not strictly causative. For instance, a behavior will start before the testosterone increases. So, it can’t be why it’s driving aggressive behavior. What does this conclude/lead to?

Answer 29

The Challenge hypothesis!

Question 30

What is the challenge hypothesis?

Answer 30

Aggressive interactions stimulate testosterone production to promote subsequent (not immediate) aggressive behavior.

Question 31

What is the Winner Effect?

Answer 31

Winning an aggressive encounter enhances the likelihood of winning subsequent encounters

Question 32

What is the winner effect likely driven by?

Answer 32

By increased testosterone (at least in vertebrates)

Question 33

What is the Bystander Effect?

Answer 33

Observing a fight between conspecifics affects testosterone levels (and future aggression). This also connects to the challenge hypothesis!