12. Cooperative Breeding Flashcards
What is cooperative breeding?
A breeding system in which individuals routinely help to rear the offspring of others
What are social breeders?
All mature females breed but no care for other’s offspring
What are communal breeders?
Several females pool young and share care - but only breeders care, and mainly for own young
What are facultative cooperative breeders?
Breeding pairs often assisted by non-breeding pairs, but pairs can and do breed alone
What are obligate cooperative breeders?
Pairs practically always assisted and rarely successful without helpers
What is the classic cooperative behaviour shown by meerkats?
Dominant breeder's monopolise reproduction Subordinate helpers (often offspring) delay dispersal, rarely breed and help to rear.
Why do helpers stay?
Shortage of vacant territory.
High mortality risk on dispersal.
Once established, low chance of successful breeding.
Why don’t helpers breed within the group?
Lack of access to unrelated breeding partners.
Reproductive coercion by the dominant.
What are the two methods of coercion?
Acts or Threats
Give some examples of acts of coercion
Mating interference, Aggression, Infanticide
Why are threats of coercion so difficult to detect?
If they are effective they are rarely exercised
Give some examples of what are thought to be hidden threats of coercion
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
Why would dominant female banded mongooses kill the offspring of others?
To reduce competition for her next litter
When are threats effective?
Three factors
- Impact (must be severe)
- Accuracy (must be targeted)
- Perception (must know how far is too far ‘line in the sand’)
Why does the threat of infanticide have such a higher impact on mammals versus insects?
Mammalian offspring are much more costly to produce
Does helping really benefit the recipients?
Helpers may ^ offspring growth and survival ^ breeder survival and repro rate lighten workload of breeders But correlation may not mean causation
Is helping costly to perform?
Helpers suffer weight-loss, ^ energetic turnover
Helping can reduce survival
What are the two classes of fitness benefit you could gain from helping?
Direct / Indirect (helping own genes or those of relatives)
How can helping have direct fitness benefits?
Group augmentation, coercion, signalling, learning skills, reciprocity, defence
