11 - Primate Mating Systems Flashcards
1
Q
Solitary
A
Orangutans
2
Q
Pair bonded
A
GIbbons
3
Q
Unifemale/multimale (polyandry)
A
Tamarins
4
Q
Unimale/multi female (polygyny)
A
Mountain gorillas
5
Q
Multimale/multifemale (polygynadry)
A
Macaques
6
Q
Strategy
A
- Set of behaviours occurring in specific functional context (e.g. folivory, polygyny
- Products of selection
7
Q
What currency should we use to measure costs
and benefits
A
- Best: reproductive success (RS): number of offspring surviving to reproductive age
- When RS difficult to measure: use proxies (e.g. foraging efficiency)
8
Q
Why is it female primates that invest more, and
not males
A
- Must carry offspring to term
- Must nurse them until they can forage independently
- Extended pregnancy (larger brains)
- Infant’s survival (hence mother’s fitness) in mammals depends on these factors, more than in other animals
9
Q
Why males invest less
A
- Male care often less important for survival of
offspring - Time, energy and resources are limited
- Paternity uncertain
- Often better strategy to use their resources to access additional females
10
Q
When will males be less involved in infant care
A
- When attracting additional mates is relatively easy (low cost)
- When fitness of offspring raised by one parent is high (benefit of additional care is minimal)
11
Q
Causes of variation in RS
A
- Females (securing resources - food)
- Males (Securing mates)
12
Q
Dominance hierarchies
A
High-ranking females gain access to more/better quality food
13
Q
Sexual selection
A
- Accounts for features with no obvious survival function (secondary sexual characteristics)
- Helps explain traits that seem costly in terms of natural selection
14
Q
Intrasexual Selection
A
- Competition within the sex(es)
- Usually stronger among males
- Common in primates
15
Q
Intersexual selection
A
- Mate choice (females choose males that will increase their fitness and show good genetic quality)
- Usually stronger in females
- Common in birds
16
Q
Common targets of intrasexual selection
A
- Increased male body size and canine size
- Often leads to sexual dimorphism
- Most pronounced in groups where males compete most (single-male/multi-female)
17
Q
Single male groups
A
- A male tries to establish residence in an unrelated group of females, and then restricts access to other males
- Other males constantly try to take over
- e.g. baboons
18
Q
Intrasexual selection in multi male groups
A
Favours increased sperm production
19
Q
RS in pair bonded males
A
- Depends more on finding mates, defending territory, and rearing surviving offspring
- Mate guarding is a common rep. strategy
20
Q
Infanticide
A
- Adaptive strategy for males
- After group takeovers, males kill dependent offspring
- Females return to estrus allowing infanticidal male to reproduce more quickly (before they are ousted)
- Infanticide is costly for females (thus have fake estrus)
21
Q
Estrus
A
Sexual swellings
22
Q
Infanticide counterstrategies
A
- Concealed ovulation
- Regularly sexually receptive
with multiple males - Terminate pregnancy
after takeover (spontaneous
abortion) - Social supports/friendships
to try to avoid infanticide
