1. What do I do? I study behavior I look at an animal’s adaptations to its environment I study Evolution

2. Animal Behavior Observe a behavior, ask 2 questions? Observe a behavior, ask 2 questions? 1) Why does animal have this behavior? 1) Why does animal have this behavior? 2) How does animal carry out this behavior? 2) How does animal carry out this behavior?

3. Animal Behavior Why? Why? Ultimate causation = evolutionary basis for existence of behavior Ultimate causation = evolutionary basis for existence of behavior How? How? Proximate causation = immediate cause and/or mechanisms underlying behavior Proximate causation = immediate cause and/or mechanisms underlying behavior

4. What is Behavioral Ecology? 1) The study of how an animal’s behavior contributes to its survival and reproduction 1) The study of how an animal’s behavior contributes to its survival and reproduction OR OR 2) How natural selection has shaped the evolution of behavior 2) How natural selection has shaped the evolution of behavior The ultimate questions

5. Behavioral ecology emphasizes evolutionary hypotheses Behavioral Ecology: Study of how organisms increase Darwinian fitness through optimal behavior Behavioral Ecology: Study of how organisms increase Darwinian fitness through optimal behavior If you can optimize behavior, then: If you can optimize behavior, then: behavior must be genetically influenced behavior must be genetically influenced behavior is subject to natural selection behavior is subject to natural selection

6. Cost/Benefit Approach B > C

7. How does a behavior benefit an individual? Benefit (and cost) in terms of reproductive success!!

8. Critical part of the adaptationist program is that all traits have negative and positive effects on an individual’s reproductive success (I.e. costs and benefits). In order to be selected for, a trait must confer more positive (benefit) than negative (cost).

9. Two main methods: Experimentation Comparative studies How do we test adaptationist hypotheses

10. The Experimental Method Example : Eggshell Removal by Gulls: Black-headed Gulls: parents always pick up the freshly hatched eggshell, and carry it away from the nest. Why? Although the young and eggs are well camouflaged, the inside of the eggshell is white and very conspicuous.

11. hypothesis  eggshell removal behavior is adaptive because it reduces the risk of predation. Benefit: reduces predation Cost: virtually no energy or time cost in moving the egg shell, but the parent must leave the new nestlings unattended. Can you think of a test of this hypothesis?

12. Test: put out cryptic eggs (n = 150) in artificial nests on the ground. Next to some (randomly distributed) put some broken egg shell. Check "nests" frequently, and record which are preyed on.

13. The Comparative Method 1. Comparison among individuals of the same species 2. Comparison between closely related species in different environments

14. The Comparative Method 1. Comparison among individuals of the same species

15. E.g. Comparing individuals that hang out in groups vs. those that are solitary

16. The Comparative Method 2. Comparison between closely related species in different environments

18. Must be careful of divergent and convergent evolution!!! (need to know an accurate phylogeny)

19. Behavioral Ecology deals with many topics including: foraging strategies foraging strategies Predator/prey dynamics Predator/prey dynamics Optimal foraging Optimal foraging communication communication alternative reproductive strategies alternative reproductive strategies mating systems mating systems Sexual selection Sexual selection Parental care Parental care social systems social systems

20. Optimal means maximize benefit and minimize cost organisms should maximize reproductive success organisms should maximize reproductive success Sometimes it is difficult to easily see what the benefit of behaviors could be… Sometimes it is difficult to easily see what the benefit of behaviors could be…

21. Why are animals social? Why group?

22. Costs of grouping Increased conspicuousness Increased conspicuousness Increased disease/parasites Increased disease/parasites Increased competition for resources Increased competition for resources Increased risk of infanticide or brood parasitism Increased risk of infanticide or brood parasitism

23. 1) Increased conspicuousness Black-tailed prairie dogs: larger colonies have greater # parasites 2) Increased parasitism

24. Benefits of grouping Detection and Defense against Predators Detection and Defense against Predators Finding food Finding food Cooperative defense of territory Cooperative defense of territory Thermoregulation Thermoregulation

25. 1. Detection and Defense against Predators 1. Get in a crowd 2. Watch together 3. Defend as a group

26. b) Feeding efficiency Examples: lions, orcas

27. c. Defend a territory together

28. e.g. Pallid Bats d. Thermoregulation – huddle to stay warm

29. Non-social Highly social Ground squirrel sociality

32. .. N Windhoek Study site

36. Female Social Groups 1-3 adult females and up to 9 subadults of either sex 1-3 adult females and up to 9 subadults of either sex One female social group in a burrow cluster One female social group in a burrow cluster Female philopatry and male-biased dispersal Female philopatry and male-biased dispersal Share sleeping burrows and a feeding range Share sleeping burrows and a feeding range Litter size is 1-2, with no male parental care Litter size is 1-2, with no male parental care

37. Males live in ALL MALE BANDS number up to 19 males together throughout the year live separately from female groups form temporary sub-bands NOT TERRITORIAL

38. Why do males live in groups? 1.Enhanced thermoregulation

39. 0510152025 0 5 10 15 20 Male group size Minimum temperature ( C) o 112

40. Why do males live in groups? 1.Enhanced thermoregulation 2. Aggregations around females

42. -3-201 0 1 2 3 4 5 6 Days from oestrus Mean interactions/h 22 30 27 21 18

43. -5-4-3-2012345 0 2 4 6 8 10 (5) (9) (11) (17) (25) (41) (28) (20) (11) (12) (10) Mean group size Days from estrus * * * * * *

44. Why do males live in groups? 1.Enhanced thermoregulation 2.Aggregations around females 3. Information exchange

45. Information Exchange Predictions: 1.Older males would be better at finding females

46. Dominant (= older) males were more likely to find estrous females than subordinate (younger) males (Spearman’s Rank Correlation, P < 0.025)

47. Information Exchange Predictions: 1.Older males would be better at finding females 2. Younger males should prefer to associate with older males in order to find females

48. Information Exchange Predictions: 1.Older males would be better at finding females 2.Younger males should prefer to associate with older males in order to find females 3. Also predicts males that tend to hang out in larger groups would have more information and thus be able to find more estrous females

49. Why do males live in groups? 1.Enhanced thermoregulation 2.Aggregations around females 3.Information exchange 4. Enhanced predator avoidance a)Vigilance b)Mobbing

52. * * * * *

54. Mobbing!!

55. Less exposure time Dilution effect Individuals in larger groups are at less risk Prediction - Group size:

59. Mobbing duration, per capita Spearman’s, P<0.01 Larger groups have less exposure time

60. Number of mobbers Spearman’s, P<0.05 Larger groups can benefit from the dilution effect

61. So Benefit to grouping But what about the costs again…for males what would be the greatest cost, in terms of reproductive success, with hanging out with other males? But what about the costs again…for males what would be the greatest cost, in terms of reproductive success, with hanging out with other males? Competition for females

62. The evolution of mating systems What are the important factors? 2 major factors: (1)Distribution of resources in time and space (2)Male parental care – is it needed for offspring survival?

63. (1)Distribution of resources in time and space a)Spatial distribution of resources: Would this be important to males or females? Female distribution theory! Males respond spatially to what females are doing!

64. b. Temporal distribution of resources – degree of asynchrony of female estrus How could this affect the mating system? Complete synchrony = monogamy Slight asynchrony = territoriality High asynchrony = dominance hierarchy

65. (2) Parental Care Factors influencing mating systems Is it needed? Lots of variability.

66. Types of mating systems Balance between environmental factors and phylogentic constraints!

67. Non-social Highly social Monogamy to polygyny to polyandry No male parental care!

68. 1) Defense polygyny (territoriality) 2) Non-defense polygyny (dominance hierarchy) 3) Competitive searching (scramble competition) Male Mating Strategies

69. Cape ground squirrel - how do males determine access to females

70. More info Linear dominance hierarchy amongst males Linear dominance hierarchy amongst males estrous lasts about 3.1 hours estrous lasts about 3.1 hours no synchrony in breeding within or between social groups no synchrony in breeding within or between social groups females can breed throughout the year females can breed throughout the year

71. Remember males are not territorial Remember males are not territorial Therefore can’t be defense polygyny

72. Older males (more dominant) are better at finding females than are younger (subordinate) males So maybe we have competitive searching going on!!!! BUT

73. 0123456 7 0 5 10 15 20 Annual number of Mates Frequency Male Cape ground squirrels mate success: Average = 2.3 females per year

74. Dominance vs. mate success Median mating score Rank

75. Can we conclude it is non-defense polygyny? Can we conclude it is non-defense polygyny? NO

76. 1 2345678910 0 1 2 3 4 5 6 Frequency Number of mates per estrus Female Cape ground squirrels:Polyandry????

77. Sperm competition Sperm compete in the reproductive tract of females

79. Studying mating systems and reproductive strategies Really looks at behavioral adaptations and directly assesses how they affect reproductive success  Really looks at behavioral adaptations and directly assesses how they affect reproductive success  And that looks directly at natural selection!!! And that looks directly at natural selection!!!