L17 - Mating system evolution Flashcards
What is monogamy?
When one male and female mate exclusively
What is single male polygyny?
When one male mates with multiple females and these females live together as a group
What is solitary polygyny?
When one male mates with multiple females and the females live in solitude
What is multi-male polygyny?
When multiple males mate with multiple females
Which mating system is usually favoured and why?
Polygyny
Because the sex that invests more into parental care is the limiting resource e.g males are limited by the number of matings they can obtain, whereas females are limited by the number of eggs they can produce
What factors shape a mating system?
- Differential investment between the sexes
- Ecological factors
- Certainty of paternity
- Dependence of young and impact of care
What ecological factors favour polygyny?
Clumped resources (uneven spread of females/ resources in different territories), high predation risk
How can certainty of paternity influence mating system?
Males who are more certain of their paternity will invest more in parental care so:
- Males certain of paternity => monogamy
- Males uncertain of paternity => polygyny
How can the dependence of offspring effect mating systems?
Both parents are more likely to help when offspring is altricial (helpless when born)
What is difference between intra and inter sexual selection?
Intra - males competing with other males
Inter - males competing for sexual choice
What is resource defence polygyny?
When males defend areas more rich in resources in which females congregate in to breed with them
What is female defence polygyny?
When males defend groups of females from other males so that they can breed with them
What scramble competition polygyny?
When females and resources are not always defendable so females are widely dispersed, males scramble to find as many mates as possible
Describe lekking polygyny
It is when mating is driven by female choice alone, males will do a courtship routine with other males helping them e.g blue mannakin bird
What are the 3 hypothesise for why males form leks rather than having territories?
- Female preference hypothesis: males cluster because females prefer sites with larger groups of males
- Hotshot hypothesis: subordinate males gather around attractive dominant males
- Hotspot hypothesis: males cluster around routes or places frequented by females
