1. ANIMAL BEHAVIOR 1. Proximate vs. Ultimate Causes 2
ANIMAL BEHAVIOR 1. Proximate vs. Ultimate Causes 2. Environment Influence + Genetic Component 3. Natural Selection favors behaviors that increase survival and reproductive success 4. Inclusive fitnessaltruistic behavior
Figure 51.1

2. Concept 51.1: Behavioral ecologists distinguish between proximate & ultimate causes of behavior
The scientific questions that can be asked about behavior can be divided into two classes
Those that focus on the immediate stimulus and mechanism for the behavior (how)
Those that explore how the behavior contributes to survival and reproduction (why)

3. Figure 51.2: African cichlid raising its fins in response to a threat.
What Is Behavior?
=what an animal does in response to some env. stimulus and how it does it
Figure 51.2: African cichlid raising its fins in response to a threat.
Dorsal fin
Anal fin

4. Proximate, or “how,” questions about behavior
Focus on the environmental stimuli that trigger a behavior
Focus on the genetic, physiological, and anatomical mechanisms underlying a behavioral act
Ultimate, or “why,” questions about behavior
Address the evolutionary significance of a behavior

5. Example - bird migration
Proximate causes
External stimuli- changes in day length
Internal stimuli - hormone levels
Ultimate causes - birds that migrate have a selective advantage over birds that don't/didn't, selected for over time; could be due to long term climate changes, glaciation, disease, taking advantage of food sources, mating.

6. ORGANISMS Nat. Sel. Environmental Gene Stimuli Pool Phenotypes
Behavior

7. 2 Components of Behavior
Nature/innate: instinct and genes determine behavior
Nurture/learned: experience and learning influence behavior
These are not working AGAINST each other.

8. Innate Programmed by genes Sterotyped (similar each time)
Developmentally fixed
Examples: kinesis, taxis, fixed-action pattern
Parental feeding - brood parasites like cuckoo bird take advantage of parents’ innate feeding of baby birds in their nest

9. Learned behavior More of a change in a behavior based on experience
Still has a genetic component (“disposition”)

10. A fixed action pattern (FAP)
Is a sequence of unlearned, innate behavior that is unchangeable
Once initiated, is usually carried to completion

11. A FAP is triggered by an external sensory stimulus (= sign stimulus)
In male stickleback, the stimulus for attack behavior is the red underside of an intruder
Figure 51.3a
(a) A male three-spined stickleback fish shows its red underside.

12. When presented with unrealistic models
As long as some red is present, the attack behavior occurs
Will this fish illicit a response?
Figure 51.3b .

13. Proximate and ultimate causes for the FAP attack behavior in male stickleback fish
ULTIMATE CAUSE: By chasing away other male sticklebacks, a male decreases the chance that eggs laid in his nesting territory will be fertilized by another male.
BEHAVIOR: A male stickleback fish attacks other male sticklebacks that invade its nesting territory.
PROXIMATE CAUSE: The red belly of the intruding male acts as a sign stimulus that releases aggression in a male stickleback.

14. Directed Movements
Many animal movements are under substantial genetic influences

15. A kinesis is a change in random activity (e. g
A kinesis is a change in random activity (e.g., turning rate) in response to changes detected in the environment
Ex: Sow bugs become more active in dry areas and less active in humid areas (but still randomly move)
Dry open area
Moist site under leaf
Kinesis increases the chance that a sow bug will encounter and stay in a moist environment—improves gas exchange, chances of finding food

16. Taxis is an oriented movement toward(+) or away (-) from a stimulus
Many stream fish exhibit positive rheotaxis whereby they automatically swim in an upstream direction
Direction
of river
current
Figure 51.7b

17. Migration
Many features of migratory behavior in birds have been found to be genetically programmed
Figure 51.8

18. Animal Signals and Communication
In behavioral ecology a signal can cause a change in another animal’s behavior
Communication = the reception of and response to signals

19. Animals communicate using
Visual, auditory, chemical, tactile, and/or electrical signals (can you think of ex?)
The type of signal used to transmit information
Is closely related to an animal’s lifestyle and environment

20. Many animals that communicate through odors emit chemical substances called pheromones
When a minnow or catfish is injured an alarm substance in the fish’s skin disperses in the water, inducing a fright response among fish in the area (communicates danger)
Figure 51.9a, b
(a) Minnows are widely dispersed in an aquarium before an alarm substance is introduced.
(b) Within seconds of the alarm substance being introduced, minnows aggregate near the bottom of the aquarium and reduce their movement.

21. Auditory Communication
Experiments with various insects have shown that courtship songs are under genetic control
Henry, Martínez, and Holsinger crossed males and females of Chrysoperla plorabunda and Chrysoperla johnsoni, two morphologically identical species of lacewings that sing different courtship songs.
EXPERIMENT
SONOGRAMS Chrysoperla plorabunda parent
Vibration volleys
Standard repeating unit
Chrysoperla johnsoni parent Volley period
crossed with
The researchers recorded and compared the songs of the male and female parents with those of the hybrid offspring that had been raised in isolation from other lacewings.
Volley period
Results: song similar to one species but interval between each song similar to the other

22. Even a variety of mammalian behaviors are under relatively strong genetic control
Research has revealed the genetic and neural basis for the mating and parental behavior of male prairie voles (see pp for more
details)
Figure 51.11

23. Concept 51.3: Environment, interacting with an animal’s genetic makeup, influences the development of behaviors
Research has revealed that environmental conditions modify many of the same behaviors
Let’s look at an example.

24. Dietary Influence on Mate Choice Behavior
One example of environmental influence on behavior Is the role of diet in mate selection by Drosophila mojavensis
Lab experiments have demonstrated that the type of food eaten during larval development influences later mate choice in females

25. Proportion of matings by Sonoran females
Figure 51.12
Results
When D. mojavensis had been raised on artificial medium, females from the Sonoran population showed a strong preference for Sonoran males (a). When D. mojavensis had been raised on cactus medium, the Sonoran females mated with Baja and Sonoran males in approximately equal frequency (b).
100 75 50 25
Artificial
Organ pipe cactus
Agria cactus
Culture medium
With Baja males
With Sonoran males
Proportion of matings by Sonoran females a b

26. CONCLUSION
The difference in mate selection shown by females that developed on different diets indicates that mate choice by females of Sonoran populations of D. mojavensis is strongly influenced by the dietary environment in which larvae develop.

27. Learned behavior = a more complex process
Learning
Learned behavior = a more complex process
Learning is the modification of behavior
Based on specific experiences
Learned behaviors
Range from very simple to very complex
Examples:

28. Imprinting
includes both learning & innate components and is generally irreversible
distinguished from other types of learning by a sensitive period = limited phase in an animal’s development that is the only time when certain behaviors can be learned

29. An example of imprinting is young geese following their mother
Konrad Lorenz showed that when baby geese spent the first few hours of their life with him, they imprinted on him as their parent

30. There are proximate and ultimate causes for this type of behavior
Figure 51.5
BEHAVIOR: Young geese follow and imprint on their mother.
PROXIMATE CAUSE: During an early, critical developmental stage, the young geese observe their mother moving away from them and calling.
ULTIMATE CAUSE: On average, geese that follow and imprint on their mother receive more care and learn necessary skills, and thus have a greater chance of surviving than those that do not follow their mother.

31. Conservation biologists have taken advantage of imprinting in programs to save the whooping crane from extinction
Figure 51.6

32. Habituation is a loss of responsiveness to stimuli that convey little or no information;
Occurs over time and is often referred to as NON-associative learning
Ex: alarm calls of prairie dogs when humans were around waned over time

33. Spatial learning is the modification of behavior based on experience with the spatial structure of the environment

34. In a classic experiment, Niko Tinbergen
Showed how digger wasps use landmarks to find the entrances to their nests
Figure 51.14
CONCLUSION
A female digger wasp excavates and cares for four or five separate underground nests, flying to each nest daily with food for the single larva in the nest. To test his hypothesis that the wasp uses visual landmarks to locate the nests, Niko Tinbergen marked one nest with a ring of pinecones.
EXPERIMENT
Nest
When the wasp returned, she flew to the center of the pinecone circle instead of to the nearby nest. Repeating the experiment with many wasps, Tinbergen obtained the same results.
RESULTS
The experiment supported the hypothesis that digger wasps use landmarks to keep track of their nests.
No Nest
After the mother visited the nest and flew away, Tinbergen moved the pinecones a few feet to one side of the nest.

35. In Associative Learning
Animals associate one feature of their environment with another
Two types:

36. Classical conditioning is a type of associative learning in which an arbitrary stimulus is associated with a reward or punishment
Animals make associations - Pavlov's dog associates bell with food, begins to salivate. Conditioned stimulus -> bell, conditioned response –> salivation w/out food.
Figure 51.15

38. Operant conditioning is another type of associative learning in which an animal learns to associate one of its behaviors with a reward or punishment
Figure 51.16
Ouch!
I won’t
try to eat
that again.

39. Cognition and Problem Solving
Cognition is the ability of an animal’s nervous system to perceive, store, process, and use information gathered by sensory receptors
Book says it is a “process of knowing involving awareness, reasoning, recollection and judgement.
Most complex form of learning

40. Problem solving can be learned by observing the behavior of other animals (= social learning)
Figure 51.17

41. Behavioral traits can evolve by natural selection
Because of the influence of genes on behavior, natural selection can result in the evolution of behavioral traits in populations.
When behavioral variation within a species corresponds to variation in the environment, it may be evidence of past evolution.

42. Variation in Prey Selection
Differences in prey selection in populations of garter snakes are due to prey availability and are evidence of behavioral evolution (p. 1135)
Slugs prevalent coastally but rare inland
Figure 51.18a, b
(a) A garter snake (Thamnophis elegans)
(b) A banana slug (Ariolimus californicus); not to scale

43. Observation by Arnold: 73% of young from coastal mothers attacked slugs vs. 35% for the inland snakes
Proximate cause: coastal snakes recognize the slugs by chemoreception
Ultimate cause: those inland snakes that colonized coastal took advantage of more abundant food source, passed on their ability to recognize, survived and increased that trait in subsequent populations

44. Optimal foraging behavior
Natural selection favors behaviors that increase survival and reproductive success
Behavior can affect fitness through its influence on foraging and mate choice
Optimal foraging behavior
Do species forage in an efficient manner that maximizes benefits of nutrition and minimizes costs of obtaining food?

45. Energy Costs and Benefits
Reto Zach
Conducted a cost-benefit analysis of feeding behavior in crows
The crows eat molluscs called whelks
But must drop them from the air to crack the shells

46. Average number of drops
Zach determined that the optimal flight height in foraging behavior
Correlated with a fewer number of drops, indicating a trade-off between energy gained (food) and energy expended 60 50
40
30
20
10 0
Average number of drops 2 3 5 7
15
Drop height preferred by crows
125
100
25
75
50
Total flight height
Total flight height (number of drops  drop height)
Height of drop (m)

47. In bluegill sunfish Prey selection behavior is related to prey density
Figure 51.23
Low prey density
High prey density
33%
32.5%
35% 2%
40%
57%
100%
50%
14%
Small prey
Medium prey
Large prey
Percentage available
Predicted percentage in diet
Observed percentage in diet
Large prey at far distance
Small prey at middle distance
Small prey at close distance

48. Mating Behavior and Mate Choice
Is the product of a form of natural selection called sexual selection
The mating relationship between males and females varies a great deal from species to species

49. In many species, mating is promiscuous
With no strong pair-bonds or lasting relationships (sorry, guys not humans)

50. In monogamous relationships
One male mates with one female
(a) Since monogamous species, such as these trumpeter swans, are often monomorphic, males and females are difficult to distinguish using external characteristics only.

51. In a system called polygyny
One male mates with many females
The males are often more showy and larger than the females
Figure 51.25b
Among polygynous species, such as elk, the male (left) is
often highly ornamented.
(b)

52. Vs. in polyandrous systems
One female mates with many males
The females are often more showy than the males
Figure 51.25c
(c) In polyandrous species, such as these Wilson’s phalaropes, females (top) are generally more ornamented than males.

53. The certainty of paternity
The needs of the young
Are an important factor constraining the evolution of mating systems
The certainty of paternity
Influences parental care and mating behavior

54. In species that produce large numbers of offspring
Parental care is at least as likely to be carried out by males as much as females
Figure 51.26
Eggs

55. Sexual Selection and Mate Choice
In intersexual selection
Members of one sex choose mates on the basis of particular characteristics (like a courtship song by males toward females)
Intrasexual selection
Involves competition among members of one sex for mates

56. Mate Choice by Females Male zebra finches
Are more ornate than females, a trait that may affect mate choice by the females
Figure 51.27

57. Parents not ornamented
Imprinting of female chicks on males with more ornamentation
Affects mate selection as adults
Experimental Groups
Control Group
Parents not ornamented
Both parents ornamented
Males
ornamented
Females
Results
Females reared by
ornamented parents
or ornamented fathers
preferred ornamented
males as mates.
ornamented mothers or
nonornamented parents
showed no preference
for either ornamented or
nonornamented males.
Males reared by all experimental groups showed no
preference for either ornamented or nonornamented
female mates.
Figure 51.19

58. Male competition for mates is a source of intrasexual selection that can reduce variation among males
Such competition may involve agonistic behavior, an often ritualized contest that determines which competitor gains access to a resource (e.g.,mate)
Figure 51.30

59. Applying Game Theory: evaluates alternative behavioral strategies in situations
Where the outcome depends on each individual’s strategy and the strategy of other individuals
Different behavioral strategies by males shows that success is relative and changes depending on the others
These lizards behave differently dep. on their coloration.

60. Mating success of male side-blotched lizards
Was found to be influenced by male polymorphism and the abundance of different males in a given area (“rock, paper, scissors”)
Orange = aggressive
Blue = defend smaller area and after less females
Yellow=sneaky
Figure 51.22
See p. 1133

61. Concept 51.6: The concept of inclusive fitness can account for most altruistic social behavior
Many social behaviors are selfish b/c natural selection favors behavior that maximizes an individual’s survival and reproduction
On occasion, some animals behave in ways that reduce their individual fitness but increase the fitness of others altruism, or selflessness

62. In naked mole rat populations
Nonreproductive individuals may sacrifice their lives protecting the reproductive individuals from predators
Figure 51.33

63. Altruistic behavior can be explained by inclusive fitness
The total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables close relatives to produce offspring

64. Hamilton’s Rule and Kin Selection
Hamilton proposed a quantitative measure
For predicting when natural selection would favor altruistic acts among related individuals
The three key variables in an altruistic act are
The benefit to the recipient
The cost to the altruist
The coefficient of relatedness

65. The coefficient of relatedness
Is the probability that two relatives may share the same genes
Figure 51.34
Parent A
Parent B  OR
Sibling 1
Sibling 2
1/2 (0.5) probability

66. Natural selection favors altruism when the benefit to the recipient
Multiplied by the coefficient of relatedness exceeds the cost to the altruist
This inequality
Is called Hamilton’s rule

67. Kin selection is the natural selection
That favors this kind of altruistic behavior by enhancing reproductive success of relatives

68. Mean distance moved from natal burrow (m)
An example of kin selection and altruism
warning behavior observed in Belding’s ground squirrels (related females closer in distance when sounding the alarm)
Male
Female
Age (months)
Mean distance moved from natal burrow (m)
300
200
100 2 3 4 12 13 14 15 25 26
Figure 5129

69. Altruistic behavior toward unrelated individuals
Reciprocal Altruism
Altruistic behavior toward unrelated individuals
Can be adaptive if the aided individual returns the favor in the future
This type of altruism
Is called reciprocal altruism (“tit for tat”more game theory)