Mating Systems Flashcards
monoandry
1 male (monogamy and polygyny)
monogyny
1 female (monogamy and polyandry)
polygamy
polygyny
polyandry
polygynandry
types of mating seystems
monogamy
polygyny
polyandry
polygynandry
types of sexual selection
intrasexual
intersexual
intrasexual
competition among sex for mate
intersexual
competition for the choice of the mate
primate mating systems
number of breeding males and females in a group
bruce effect
when females terminate their pregnancy after exposure to unfamillair male
example of primates with bruce effect
wild geladas
humans
langurs
pregnant mice
Secondary sexual characteristics
those physical characteristics that differentiate male and female individuals that are not directly related to reproduction and usually appear at sexual maturity; these include hair growth and coloration as well as body size and muscle development
Sexual selection theory
bodies–> shaped by conspecifics
individuals are able to attract more mates by being more attractive to individuals of the opposite sex;
this attractiveness is based on physical characteristics that may be also linked to social dominance or overall health
(secondary traits selected for to gain mates attention)
estrus
when fertilization occurs in females
natural selection
bodies shaped by outside forces like climate/ecology/predators/etc.
somatic selection
factors determining body SIZE
assosciated with male competition
(darwin)
internal selection mechanisms
- roger short: genital selection
- cryptic female choice
- sperm competition
cryptic female choice
west-eberhard; effect of female genital tract on sperm
sperm competition
ability of male sperm to reach female ovum
grouping system…
who lives with whom
mating system…
who mates with whom
breeding system..
who reproduces with whom
coitus
lenght of copulation
monogamy body size
equal (monomorphic)
polygnous body size
males MUCH bigger than females
polygyandrous body size
males somewhat bigger than females (mild sexual dimorphism)
polyandrous body size
females bigger than males
in what mating systems do sexual swellings occur
polygyandrous systems
at times in polyandries
where is coitus long
moogamy and polygyny
example of sexual monomorphism
gibbons
marmosets (high paternity certainy and parental investment)
why are males bigger than females sometimes
high male to male competition
to dominant females
(in polygnous and polygyandrous systems)
why do female barbarcy macaques + baboons produce sexual swellings
- attract males
2. showcase ovulation
effects of sexual swellings
- high energy to create them (add to body weight)
2. variances of size/colour/shape= indicate evolutionary fitness
role of testes size
- for post-copulatory compeititon (sperm compeitiont for paternity likelihood)
- big balls= high energy cost to manintain but more effective; more in polygynadrous/polyandrous societies
- small balls- in polygynous as males have more choice (picky); thus want to reduce female aggrssion and energy costs of having big teseticles
polyandrous grouping composition of infants
one male series all infants and suborindate males remain to help alpha males kind to reproduce
possible strategy for a male when there is a female solitary
- join with female + exclude others (monogamy)
- repel invaidators in territory where solitary female is
- join with other males and raise one female offspring (allomothering)
- ally with other males to defned several scattered females (brother bads)
where are extended matrillines found
in macaques and muriquis (old world monkeys)
why do matrillines exist
increased protection and surivval
shared parenting
matrillines
a group all related by the female lineage
old world monkeys; common group structure?
The classic story with old world monkeys is that they’re like most mammals in that it’s the males who disperse and the females who remain in their natal group.
You get a female bonded social organization. There are several matrilines in a group. (Matrilines are females who are all related through their maternal lines.)
The males who are there are immigrants or are juveniles who haven’t emigrated yet.
The females form the social core of the group and they have a stable dominance hierarchy. (The male dominance hierarchies are usually really volatile.)
male to male competition for mattrilinez…affected by…
is very high and affected by:
1. size/cohesion of female group (determien whether only 1 male has access)
- reproductive synchroncy
challenges for males trying to access a group of females
- overcome resistance of present males (dominace hirarchies)
- female coopertaion
- intergroup encounters
extra group copulations definition
when non-group members compete with in group members for sex; resulting in females resieving indirect benefits, such as disease resitance genes, by mating with outsiders and insiders trying to male guard females
seasonal metapormisis
when males gain seasonal size changes (hair, testes) for sperm competition and start becomign more aggresive (teststonerone, cortisol levels, spermatogensis)
creates ‘fatted alphan males’
where does seasonal metamophirissi occur
central american squirrel monkeys
sifakas
capuchins
seasonal dominance hierarhcies
seasonal aggression in males to when females are in breeding sseaon
