12. Cooperative Breeding

Question 1

What is cooperative breeding?

Answer 1

A breeding system in which individuals routinely help to rear the offspring of others

Question 2

What are social breeders?

Answer 2

All mature females breed but no care for other’s offspring

Question 3

What are communal breeders?

Answer 3

Several females pool young and share care - but only breeders care, and mainly for own young

Question 4

What are facultative cooperative breeders?

Answer 4

Breeding pairs often assisted by non-breeding pairs, but pairs can and do breed alone

Question 5

What are obligate cooperative breeders?

Answer 5

Pairs practically always assisted and rarely successful without helpers

Question 6

What is the classic cooperative behaviour shown by meerkats?

Answer 6

Dominant breeder's monopolise reproduction
Subordinate helpers (often offspring) delay dispersal, rarely breed and help to rear.

Question 7

Why do helpers stay?

Answer 7

Shortage of vacant territory.
High mortality risk on dispersal.
Once established, low chance of successful breeding.

Question 8

Why don’t helpers breed within the group?

Answer 8

Lack of access to unrelated breeding partners.

Reproductive coercion by the dominant.

Question 9

What are the two methods of coercion?

Answer 9

Acts or Threats

Question 10

Give some examples of acts of coercion

Answer 10

Mating interference, Aggression, Infanticide

Question 11

Why are threats of coercion so difficult to detect?

Answer 11

If they are effective they are rarely exercised

Question 12

Give some examples of what are thought to be hidden threats of coercion

Answer 12

Goby - Hidden threat of eviction leads to growth restraint
Banded mongooses - Hidden threat of infanticide leads to extreme birth synchrony - pregnant dominant females will kill all new young if guaranteed to be not her own

Question 13

Why would dominant female banded mongooses kill the offspring of others?

Answer 13

To reduce competition for her next litter

Question 14

When are threats effective?

Answer 14

Three factors

• Impact (must be severe)
• Accuracy (must be targeted)
• Perception (must know how far is too far ‘line in the sand’)

Question 15

Why does the threat of infanticide have such a higher impact on mammals versus insects?

Answer 15

Mammalian offspring are much more costly to produce

Question 16

Does helping really benefit the recipients?

Answer 16

Helpers may 
^ offspring growth and survival
^ breeder survival and repro rate
lighten workload of breeders
But correlation may not mean causation

Question 17

Is helping costly to perform?

Answer 17

Helpers suffer weight-loss, ^ energetic turnover

Helping can reduce survival

Question 18

What are the two classes of fitness benefit you could gain from helping?

Answer 18

Direct / Indirect (helping own genes or those of relatives)

Question 19

How can helping have direct fitness benefits?

Answer 19

Group augmentation, coercion, signalling, learning skills, reciprocity, defence