Lavc f10 lecture 10 primate ecology


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Anthro 101:Human Biological Evolution lecture on Primate Ecology. Rebecca Frank, LAVC F2010

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  • Crowned hawk eagle - 80% diet monkey
  • Lavc f10 lecture 10 primate ecology

    1. 1. Anthro 101: Human Biological Evolution Lecture 10: Primate Ecology Office Drop-in Hours AHS 308 Tutoring Lab Hours AHS 232 T 5:30 - 6:30 M & T 1 - 4 Th 11:15 - 12:15, 1:15 - 3:15 Student ID required F 12 - 1:30 by appointment
    2. 2. Attendance survey <ul><li>List three primate characteristics that differentiate primates from other mammals. </li></ul><ul><li>Write your name on the other side of the card. </li></ul>
    3. 3. Zoo Project - any questions? <ul><li>Friday Oct. 15th & Saturday Oct. 16th @ 9:45 </li></ul><ul><li>Due Oct. 21st - 3rd Exam Oct. 21st </li></ul><ul><li>Exam 2 Extra Credit - fix your mistakes and show me or Kirsten - Due Oct. 21st </li></ul><ul><li>Optional Fieldtrip - any interest? </li></ul><ul><li>Natural History Museum - Age of Mammals </li></ul><ul><li>Sun. Nov. 7th or Sat. Nov. 20th or Sun. Nov. 21st </li></ul><ul><li>$6.50 admission, free parking, near USC </li></ul>
    4. 4. Why do primates live in groups? <ul><li>Advantages of group life </li></ul><ul><li>Costs of group life </li></ul><ul><li>Why do primates live in so many kinds of groups? </li></ul><ul><ul><li>Balancing costs & benefits </li></ul></ul><ul><ul><li>Socioecology </li></ul></ul>
    5. 5. Behavioral Ecology <ul><li>The study of the evolution of behavior </li></ul><ul><li>emphasizing the role of ecological factors as agents of natural selection </li></ul><ul><ul><li>Resources (diet), predators, climate, “conspecifics,” etc. </li></ul></ul><ul><ul><li>How do these factors affect behavior? </li></ul></ul><ul><ul><li>In primates, focus especially on the influence of these on social organization </li></ul></ul><ul><li>Socioecology : the study of how social structure and organization are influenced by organisms' environment </li></ul>
    6. 6. 1. Why do primates live in groups? <ul><li>Most mammals are solitary </li></ul><ul><li>Many prosimians solitary </li></ul><ul><li>Why are diurnal primates social? </li></ul>
    7. 7. Major benefits of group life <ul><li>Protection versus predators </li></ul><ul><li>Better access to resources </li></ul><ul><li>Access to potential mates </li></ul>
    8. 8. Large cats prey on primates lion leopard jaguar cheetah tiger
    9. 9. Large primates can defend themselves against big cats, but many small ones can’t
    10. 10. Raptors prey on primates Martial eagle Harpy eagle Hawk eagle
    11. 11. Crocodiles can take primates
    12. 12. A variety of snakes prey on primates python
    13. 13. Primates prey on other primates Chimps hunt red colobus monkeys Baboons prey on vervets
    14. 14. Humans and domestic dogs kill primates Hunter with gorilla head Dog with langur infant
    15. 15. Predation is rarely observed, but can sometimes be inferred leopard paw print drag marks baboon jaw & hair
    16. 16. Indirect evidence of predation <ul><li>Wound observed </li></ul><ul><li>Healthy animals disappear overnight </li></ul>Juvenile, scalp wound Oryx, back wound
    17. 17. For diurnal primates, sociality is an effective anti-predator strategy <ul><li>Detection </li></ul><ul><li>Dilution </li></ul><ul><li>Defense </li></ul>
    18. 18. Detection : In larger groups, there are more eyes to watch out for predators
    19. 19. Dilution : In groups, any particular individual less likely to be caught by predator <ul><li>Imagine chance of being caught = 1/ n , where n = group size </li></ul>risk = 1/2 risk = 1/12                            
    20. 20. Defense : Many strategies for diurnal primates <ul><li>Sleep in trees, cliffs </li></ul><ul><li>Defensive weaponry </li></ul><ul><li>Large body size </li></ul><ul><li>Vigilance </li></ul><ul><li>Alarm calls </li></ul><ul><li>Mobbing </li></ul><ul><li>Interspecific associations </li></ul>
    21. 21. Two or more species may associate to reduce predator risk: Interspecific Associations - 3D’s Ground predators Eagles Diana monkey Red colobus
    22. 22. Nocturnal primates use different strategies <ul><li>Hide during day </li></ul><ul><li>Park infants while feeding </li></ul><ul><li>Solitary </li></ul><ul><li>Quiet </li></ul><ul><li>Cryptic </li></ul>
    23. 23. Sociality also has costs <ul><li>Competition </li></ul><ul><li>Contagion </li></ul><ul><li>Cuckoldry </li></ul><ul><li>Inbreeding </li></ul><ul><li>Cannibalism </li></ul><ul><li>Infanticide </li></ul>
    24. 24. 2. Natural selection shapes social organization to balance the costs & benefits of group living <ul><li>Socioecology = study of how ecological forces shape the size and structure of social groups </li></ul>
    25. 25. Solitary (but differentiated social relationships) <ul><li>each individual lives alone, occasionally meet up for mating </li></ul><ul><li>may chose to neighbour with kin, meet more often </li></ul>Orangutan Loris
    26. 26. Monogamous (territorial pairs + offspring) Titi monkeys Gibbons
    27. 27. One-male, Multi-female groups (polygyny) Mountain gorillas Black and white colobus
    28. 28. One-female, two-male groups (Polyandry) Pygmy marmoset marmoset Callitrichids
    29. 29. Multi-male, multi-female groups Ring-tailed lemurs Savanna baboons
    30. 30. Communities (fission-fusion social organization) Spider monkeys Chimpanzees
    31. 31. Socioecology : Competition for food is particularly important for females <ul><li>Nutrition affects: </li></ul><ul><ul><li>Ability to conceive </li></ul></ul><ul><ul><li>Viability of pregnancy </li></ul></ul><ul><ul><li>Lactation </li></ul></ul><ul><li>Male reproduction is more influenced by access to females than by nutrition </li></ul>
    32. 32. Food, competition, and social behavior are thought to be linked Dominance Relationships Competitive Regime Distribution of food Value of Alliances Female Relationships Dispersal Patterns
    33. 33. The distribution of food affects they type of competition <ul><li>Clumped, valuable patches </li></ul><ul><li>Dispersed, low value patches </li></ul>
    34. 34. The distribution of food affects the nature of competition <ul><li>Dispersed --> scramble competition </li></ul><ul><ul><li>Food is distributed evenly </li></ul></ul><ul><ul><li>Food items not worth fighting over </li></ul></ul><ul><ul><li>Scramble to get enough food </li></ul></ul><ul><ul><li>no direct competition </li></ul></ul><ul><li>Clumped --> contest competition </li></ul><ul><ul><li>Resources are scarce & valuable </li></ul></ul><ul><ul><li>Resources are worth fighting over </li></ul></ul><ul><ul><li>Contest access to particular resources </li></ul></ul>
    35. 35. Contest competition can produce dominance relationships <ul><li>A & B want same piece of food  FIGHT </li></ul><ul><li>Bigger, stronger, more experienced one will win </li></ul><ul><li>When one consistently defeats other = dominance relationship </li></ul><ul><li>If A always beats B & C </li></ul><ul><li>And B always beats C </li></ul><ul><li>= dominance hierarchy </li></ul>
    36. 36. Food, competition, and social behavior are thought to be linked Dominance Hierarchy Contest Competition Distribution of food Value of Alliances Female Relationships Dispersal Patterns
    37. 37. If dominance rank affects access to resources, <ul><li>Females will strive for high rank </li></ul><ul><li>Females may benefit from help in their fights </li></ul><ul><ul><li>Alliances useful </li></ul></ul>
    38. 38. If females come to rely on alliances… <ul><li>Will develop relationships with allies </li></ul><ul><ul><li> associate with certain females </li></ul></ul><ul><ul><li> groom certain females </li></ul></ul><ul><li>May prefer kin as allies </li></ul><ul><ul><li>Kin share genes = kin selection </li></ul></ul><ul><ul><li>Inclusive fitness </li></ul></ul><ul><li>Will remain with allies/kin </li></ul><ul><ul><li>Females will be philopatric </li></ul></ul><ul><ul><li>Males will disperse to prevent inbreeding </li></ul></ul>
    39. 39. Alliances can also affect structure of dominance relationships <ul><li>A beats B </li></ul><ul><li>A helps A’ beat B </li></ul><ul><li>A’ can beat B </li></ul><ul><li>A and A’ will outrank B </li></ul><ul><li>Dominance hierarchy will have female relatives next to each other in rank </li></ul>Monkey B Monkey A Monkey A’
    40. 40. Food, competition, and social behavior are thought to be linked Dominance Hierarchy Contest Competition Distribution of food Alliances Valuable Close Bonds Female Philopatry Eg: baboons & capuchins
    41. 41. If dominance does not affect access to resources, then… Unstable hierarchy Scramble Distribution of food Eg: gorillas & langur monkeys Weak bonds Male/female dispersal No alliances
    42. 42. What about males? <ul><li>There are differences between sexes in what matters most for fitness: </li></ul><ul><ul><li>Female fitness depends on access to resources </li></ul></ul><ul><ul><li>Male fitness depends on access to females </li></ul></ul><ul><li>Social organization depends on: </li></ul><ul><ul><li>Distribution of resources (for females) </li></ul></ul><ul><ul><li>Distribution of females (for males) </li></ul></ul><ul><li> Social organization is driven by sex differences. Why? </li></ul>
    43. 43. What about males? <ul><li>Male fitness depends mainly on access to females </li></ul><ul><li>Males don’t benefit much from alliances - can’t share mating opportunities very well </li></ul><ul><li>So, males go where females are </li></ul>