Title: Mating%20Systems
1Mating Systems
- Causes
- Types and distribution
- Ecological factors
- Polygyny threshold
- Polyandry
2Causes of spacing patterns
Males disperse in space to maximize mating
opportunities with females
3Parental care and female dispersion influence
mating system
4Monogamy
Lar gibbon
Silver-backed jackal
5Social monogamy
- gt 90 of all birds, most biparental care
- lt 10 of all mammals
- males help provision young
- canids, marmosets,carnivorous bats
- males defend single female
- dik-dik, some rodents
- Rare in
- insects (carrion beetles)
- Fishes, reptiles, amphibians
6Mate assistance in Peromyscus californicus
7Mate assistance monogamy in snow buntings
8Social monogamy ? genetic monogamy
9Polygyny (gt 90 of mammals)
10Ecological correlates of polygyny
- Females solitary, but ranges defensible by male
- prosimian primates
- Females solitary, range not defensible
- Moose, orangutan
- Females social, range defensible
- Seasonal harems - elephant seals, red deer
- Permanent harems - baboons, zebra, spear-nosed
bats - Females social, range not defensible
- Female movements unpredictable
- males follow females, e.g. elephants
- Female movements predictable - males display on
leks
11Polygyny (lt 10 of birds)
- Males defend food or nesting sites
- Blackbirds
- Grouse
- Cotingas
12Ecological factors affecting polygyny
- Female sociality
- Female movement predictability
- Habitat heterogeneity
13Habitat heterogeneity
- If there is spatial habitat heterogeneity
- And fixed territory size
- Then females will have to choose between unmated
males on poor territories or mated males on rich
territories or - If territory size is related to size or age
- Then females should choose largest territory
14Resource defense polygyny
15Polygyny threshold model
16Polygyny threshold predictions
- Polygyny should be most common in patchy habitats
- Male territory quality influences of females
- Females mating to already mated males should have
RS comparable to females pairing with unmated
males
17Polygyny in pied flycatchers
18Polygyny in anolis lizards depends on size
19Polyandry
- Rare in birds
- Sequential - sanderling, stint
- Simultaneous - phalarope, jacana
- Cooperative - pukeko
- Very rare in mammals
- Tamarins
- Common in fish
20Ecological reasons for polyandry
- Rich resource, eggs are cheap
- Short breeding season
- Male biased sex ratio
21Why should females multiple mate?
22Pseudoscorpions gain fertility benefit
23Human mating systems