31-Living in Groups

Question 1

What are the universal problems in group living?

Answer 1

1. Increased intensity of competition for resources/mates (universal).
2. Increased likelihood of disease and parasite transmission (universal).
3. Increased conspicuousness of predators or prey (depends on environment).

Question 2

What are the advantages of group living for prey?

Answer 2

Nature of food resources may make splintering off unprofitable (large prey or patchy prey).
Cooperative hunting and protection.

Question 3

What are the advantages of group living for predators?

Answer 3

Susceptibility to predation may be lowered because of aggressive group defense or because of opportunity for individuals to use the group as cover.
Group defense by mobbing guillemots (reducing their domain of danger)

Question 4

Under what circumstances can optimal flock size be shifted?

Answer 4

During the presence of predator.

Question 5

When is flocking advantageous for food even if the expected rate of food intake is the same?

Answer 5

Flocking is advantageous for food only when N individuals find patches of food more the N times the rate that an individual finds patches. Is advantageous if they are safer in groups

Question 6

What is the difference between the encounter and the dilution effect?

Answer 6

The encounter effect assumes that the probability of encountering a group is independent of group size. The dilution effect assumes that only one individual is taken from a group once encountered.