Cooperative Breeding Flashcards
What is altruism?
An extreme form of co-operation, involving unselfish behaviour performed for the benefit of others.
What 3 hypotheses explain the evolution of altruism?
- Kin selection - altruism is favoured when recipient shares same genes as donor.
- Reciprocal altruism - donor performs altruistic act in expectation that ‘favour’ will be returned one day.
- By-product mutualism - donor & recipient gain survival benefit from co-operative act (e.g. alloparenting).
What is solitary, colonial and communal breeding?
- Solitary = no co-operation or in monogamy, co-operation between parents.
- Colonial = several (or many) breeding pairs share breeding site but there’s no active co-operation.
- Communal = group members co-operate for reproduction & participate in co-operation.
What is eusociality?
- Specialisation between reproductive individuals & several sterile castes.
- E.g. some castes are responsible for foraging & defence (bees, wasps & some termites).
What is co-operative breeding?
A system in which tasks associated with breeding & rearing young are shared between individuals & helpers.
What are the 2 components of inclusive fitness?
- Direct fitness - personal reproductive success (i.e. offspring).
- Indirect fitness - through reproductive success of relatives.
What are the 2 main types of co-operative breeding?
- Helpers at nest/den - a breeding pair with helpers.
- Plural breeders - more than 1 breeding pairs, extended family groups, overlapping generations.
Give an example of helpers.
- Florida scrub jay.
- Groups consist of a monogamous pair & 1-6 helpers.
What do the helpers do?
- Defend natal territory.
- Help feed young.
- Defend nest when adults are away.
- Protect fledglings.
- Act as sentinels.
- Usually leave pair after a couple of years.
Give an example of plural breeders.
- Mexican jay.
- Lives in extended family groups
- Several breeding pairs in each group.
- Helpers assist in feeding young & nest defence.
- When fledged, young are fed by all group members.
Give an example of an obligate co-operative breeder.
Ground hornbills.
What are the benefits of helpers?
- Increased success of breeding attempts.
- Increased frequency of breeding.
- May grow faster.
- Fed more.
- Enhanced breeder survival.
- Increased fecundity in helpers.
- Increased production of non-descendent kin for helpers.
What is the habitat saturation hypothesis?
- Lack of vacant territories.
- Some species need a territory to breed & available habitat or territories may be limiting.