Cooperative Breeding Flashcards
Describe helpers in the nest + give some examples
- Help at the nest, feed and protect
- Usually a sibling
- Most common form of cooperative breeding
Examples: - Florida scrub jay
- Naked mole rats (primitive eusocial?)
Describe plural breeding and give some examples
- Several males and females share a nest and raise a communal brood
- E.g Banded mongoose
- Acorn woodpecker
Describe the Ecological Constraints Hypothesis (Emlen 1982)
Describes how cooperative breeding evolved:
What is the key assumption of the Ecological constraints hypothesis?
That if helpers had the opportunity to breed then they would (because it’s their best option)
What hypothesis explains why helpers benefit from helping
Kin selection
(relies on inclusive fitness)
Describe inclusive fitness
Name 2 direct fitness benefits for helpers
- Increased survival
- Increased probability of future breeding
Describe the Group Augmentation Hypothesis
(increased survival for helpers)
- Producing extra offspring benefits helpers by increased group size (dilution effect)
- Circumstantial evidence:
Banded mongoose kidnapping to increase group size
Cichlid groups more likely to accept immigrants when predation risk high
Describe how helpers gain increased probability of future breeding (with examples)
- Territory: E.g Florida scrub jay → 48% of helpers eventually acquire all/part of parental territory
- Mate acquisition: e.g Pied kingfisher:
- Increased experience (skills hypothesis)
Describe how helpers benefit from increased reproductive success of relatives
E.g long-tailed tit
- Helpers increases offspring survival by 40%
= big indirect fitness payoff
Describe how helpers benefit from the increased survival of related breeders
→ load-lightening
Helpers lower effort of breeders = improves parental survival
