1. Mating Systems Causes Types and distribution Ecological factors –Polygyny threshold –Polyandry

2. Causes of spacing patterns Males disperse in space to maximize mating opportunities with females

3. Parental care and female dispersion influence mating system

4. Monogamy Lar gibbon Silver-backed jackal

5. Social monogamy > 90% of all birds, most biparental care < 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

6. Mate assistance in Peromyscus californicus

7. Mate assistance monogamy in snow buntings

8. Social monogamy ≠ genetic monogamy

9. Polygyny (> 90% of mammals)

10. Ecological 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

11. Polygyny (< 10% of birds) Males defend food or nesting sites –Blackbirds –Grouse –Cotingas

12. Ecological factors affecting polygyny Female sociality Female movement predictability Habitat heterogeneity

13. 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

14. Resource defense polygyny

15. Polygyny threshold model

16. Polygyny 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

17. Polygyny in pied flycatchers

18. Polygyny in anolis lizards depends on size

19. Polyandry Rare in birds –Sequential - sanderling, stint –Simultaneous - phalarope, jacana –Cooperative - pukeko Very rare in mammals –Tamarins Common in fish

20. Ecological reasons for polyandry Rich resource, eggs are cheap Short breeding season Male biased sex ratio

21. Why should females multiple mate?

22. Pseudoscorpions gain fertility benefit

23. Human mating systems