1. Chapter 51
Behavioral Ecology

2. Overview: Studying Behavior
Humans have probably studied animal behavior
For as long as we have lived on Earth
As hunters
Knowledge of animal behavior was essential to human survival

3. The modern scientific discipline of behavioral ecology
Extends observations of animal behavior by studying how such behavior is controlled and how it develops, evolves, and contributes to survival and reproductive success

4. Concept 51.1: Behavioral ecologists distinguish between proximate and 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
Those that explore how the behavior contributes to survival and reproduction

5. What Is Behavior? Behavior Is what an animal does and how it does it
Includes muscular and nonmuscular activity
Figure 51.2
Dorsal fin
Anal fin

6. Learning
Is also considered a behavioral process

7. Proximate and Ultimate Questions
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

8. Ultimate, or “why,” questions about behavior
Address the evolutionary significance of a behavior
Ethology is the scientific study of animal behavior
Particularly in natural environments

9. Mid 20th-century ethologists
Developed a conceptual framework defined by a set of questions
These questions
Highlight the complementary nature of proximate and ultimate perspectives

10. A fixed action pattern (FAP)
Fixed Action Patterns
A fixed action pattern (FAP)
Is a sequence of unlearned, innate behaviors that is unchangeable
Once initiated, is usually carried to completion
A FAP is triggered by an external sensory stimulus
Known as a sign stimulus

11. In male stickleback fish, 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
Figure 51.3b
(b) The realistic model at the top, without a red underside, produces no aggressive response in a male three-spined stickleback fish. The other models, with red undersides, produce strong responses.

13. Proximate and ultimate causes for the FAP attack behavior in male stickleback fish
Figure 51.4
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. Imprinting is a type of behavior
That includes both learning and innate components and is generally irreversible
Imprinting is distinguished from other types of learning by a sensitive period
A limited phase in an animal’s development that is the only time when certain behaviors can be learned

15. 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

16. 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.

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

18. Concept 51.2: Many behaviors have a strong genetic component
Biologists study the ways both genes and the environment
Influence the development of behavioral phenotypes
Behavior that is developmentally fixed
Is called innate behavior and is under strong genetic influence

19. These types of movements
Directed Movements
Many animal movements
Are under substantial genetic influence
These types of movements
Are called directed movements
A kinesis
Is a simple change in activity or turning rate in response to a stimulus

20. Sow bugs
Become more active in dry areas and less active in humid areas
Figure 51.7a
Dry open area
Moist site under leaf
(a) Kinesis increases the chance that a sow bug will encounter and stay in a moist environment.

21. Taxis
A taxis
Is a more or less automatic, oriented movement toward or away from a stimulus

22. Many stream fish exhibit positive rheotaxis
Where they automatically swim in an upstream direction
Direction
of river
current
(b) Positive rheotaxis keeps trout facing into the current, the direction from which most food comes.
Figure 51.7b

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

24. Animal Signals and Communication
In behavioral ecology
A signal is a behavior that causes a change in another animal’s behavior
Communication
Is the reception of and response to signals

25. Animals communicate using
Visual, auditory, chemical, tactile, and electrical signals
The type of signal used to transmit information
Is closely related to an animal’s lifestyle and environment
Many animals that communicate through odors
Emit chemical substances called pheromones

26. 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
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.

27. Auditory Communication
Experiments with various insects
Have shown that courtship songs are under genetic control
Charles Henry, Lucía Martínez, and ent 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

28. The F1 hybrid offspring sing a song in which the length of the standard repeating unit is similar to that sung by the Chrysoperla plorabunda parent, but the volley period, that is, the interval between vibration volleys, is more similar to that of the Chrysoperla johnsoni parent.
RESULTS
The results of this experiment indicate that the songs sung by Chrysoperla plorabunda and Chrysoperla johnsoni are under genetic control.
CONCLUSION
Standard repeating unit
Volley period
F1 hybrids, typical phenotype

29. Research has revealed the genetic and neural basis
For the mating and parental behavior of male prairie voles
Figure 51.11

30. 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

31. Dietary Influence on Mate Choice Behavior
One example of environmental influence on behavior
Is the role of diet in mate selection by Drosophila mojavensis

32. Proportion of matings by Sonoran females
Laboratory experiments have demonstrated
That the type of food eaten during larval development influences later mate choice in females
Figure 51.12
William Etges raised a D. mojavensis population from Baja California and a D. mojavensis population from Sonora on three different culture media: artificial medium, agria cactus (the Baja host plant), and organ pipe cactus (the Sonoran host plant). From each culture medium, Etges collected 15 male and female Baja D. mojavensis pairs and 15 Sonoran pairs and observed the numbers of matings between males and females from the two populations.
EXPERIMENT
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).
RESULTS
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.
CONCLUSION
100 75 50 25
Artificial
Organ pipe cactus
Agria cactus
Culture medium
With Baja males
With Sonoran males
(b)
Proportion of matings by Sonoran females
(a)

33. Therese Markow and Eric Toolson proposed
That the physiological basis for the observed mate preferences was differences in hydrocarbons in the exoskeletons of the flies
Figure 51.13

34. Social Environment and Aggressive Behavior
Cross-fostering studies in California mice and white-footed mice
Have uncovered an influence of social environment on the aggressive and parental behaviors of these mice

35. Influence of cross-fostering on male mice
Table 51.1

36. Learning is the modification of behavior
Based on specific experiences
Learned behaviors
Range from very simple to very complex
Habituation
Is a loss of responsiveness to stimuli that convey little or no information

37. Spatial learning is the modification of behavior
Based on experience with the spatial structure of the environment

38. 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.

39. In associative learning
Cognitive Maps
A cognitive map
Is an internal representation of the spatial relationships between objects in an animal’s surroundings
In associative learning
Animals associate one feature of their environment with another

40. Classical conditioning is a type of associative learning
In which an arbitrary stimulus is associated with a reward or punishment
Before stimulus
Influx of water alone
Influx of alarm substances
Influx of pike odor
Day 1
Day 3
Control group
Experimental group
Experimental group
Relative activity level
Figure 51.15

41. 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

42. 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

43. Problem solving can be learned7
Problem solving can be learned
By observing the behavior of other animals
Figure 51.17

44. Genetic and Environmental Interaction in Learning
Genetics and environment can interact
To influence the learning process
Concept 51.4: 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

45. Behavioral Variation in Natural Populations
When behavioral variation within a species
Corresponds to variation in the environment, it may be evidence of past evolution

46. Variation in Prey Selection
Differences in prey selection in populations of garter snakes
Are due to prey availability and are evidence of behavioral evolution
Figure 51.18a, b
(a) A garter snake (Thamnophis elegans)
(b) A banana slug (Ariolimus californicus); not to scale

47. Variation in Aggressive Behavior
Funnel spiders living in different habitats
Exhibit differing degrees of aggressiveness in defense and foraging behavior 50
40
30
20
10 0
Time to attack (seconds)
Field
Lab-raised
generation 1
generation 2
Desert grassland population
Riparian population 60
Population
Figure 51.19

48. Experimental Evidence for Behavioral Evolution
Laboratory and field experiments
Can demonstrate the evolution of behavior

49. Laboratory Studies of Drosophila Foraging Behavior
Studies of Drosophila populations raised in high- and low-density conditions
Show a clear divergence in behavior linked to specific genes 14 12
10 8 6 2 0
Average path length (cm) 4 L1 L2 L3 H1 H2 H3 H4 H5
D. Melanogaster lineages
Low population density
High population density
Figure 51.20

50. Migratory Patterns in Blackcaps
Field and laboratory studies of Blackcap birds
Have documented a change in their migratory behavior

51. Birds placed in funnel cages
Left marks indicating the direction they were trying to migrate
Figure 51.21a
(a) Blackcaps placed in a funnel cage left marks indicating the direction in which they were trying to migrate.

52. Migratory orientation of wintering adult birds captured in Britain
Was very similar to that of laboratory-raised birds
Figure 51.21b
(b) Wintering blackcaps captured in Britain and their laboratory-raised offspring had a migratory orientation toward the west, while young birds from Germany were oriented toward the southwest. N E S W
Adults from Britain and F1 offspring of British adults
Young from SW Germany
Mediterranean Sea
BRITAIN
GERMANY

53. The genetic components of behavior
Concept 51.5: Natural selection favors behaviors that increase survival and reproductive success
The genetic components of behavior
Evolve through natural selection
Behavior can affect fitness
Through its influence on foraging and mate choice

54. Optimal foraging theory
Foraging Behavior
Optimal foraging theory
Views foraging behavior as a compromise between the benefits of nutrition and the costs of obtaining food
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

55. 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)
Figure 51.22
Height of drop (m)

56. 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

57. Research on mule deer populations
Risk of Predation
Research on mule deer populations
Has shown that predation risk affects where the deer choose to feed
Figure 51.24 70 60
40
30
20
10 0
Predation occurrence (%) 50
Relative deer use
Predation risk
Open
Forest edge Habitat
Forest interior 5
15

58. Mating Behavior and Mate Choice
Is the product of a form of natural selection call sexual selection
The mating relationship between males and females
Varies a great deal from species to species
In many species, mating is promiscuous
With no strong pair-bonds or lasting relationships

59. In monogamous relationships
One male mates with one female
Figure 51.25a
(a) Since monogamous species, such as these trumpeter swans, are often monomorphic, males and females are difficult to distinguish using external characteristics only.

60. 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)

61. 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.

62. 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

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

64. Sexual Selection and Mate Choice
In intersexual selection
Members of one sex choose mates on the basis of particular characteristics
Intrasexual selection
Involves competition among members of one sex for mates

65. 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

66. 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 51.28

67. The size of eyestalks in stalk-eyed flies
Affects which males the females choose to mate with
Figure 51.29

68. Male Competition for Mates Male competition for mates
Is a source of intrasexual selection that can reduce variation among males

69. Such competition may involve agonistic behavior
An often ritualized contest that determines which competitor gains access to a resource
Figure 51.30

70. Morphology affects the mating behavior
In isopods of the same species that are genetically distinct
Figure 51.31
Large Paracerceis  males defend harems of females within intertidal sponges.   
Tiny  males are able to invade and live within large harems.
 males mimic female morphology and behavior and do not elicit a defensive reponse in  males and so are able to gain access to guarded harems.

71. Game theory evaluates alternative behavioral strategies in situations
Applying Game Theory
Game theory evaluates alternative behavioral strategies in situations
Where the outcome depends on each individual’s strategy and the strategy of other individuals

72. 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
Figure 51.32

73. Many social behaviors are selfish Natural selection favors behavior
Concept 51.6: The concept of inclusive fitness can account for most altruistic social behavior
Many social behaviors are selfish
Natural selection favors behavior
That maximizes an individual’s survival and reproduction

74. On occasion, some animals
Altruism
On occasion, some animals
Behave in ways that reduce their individual fitness but increase the fitness of others
This kind of behavior
Is called altruism, or selflessness

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

76. 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

77. 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

78. 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

79. 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

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

81. Mean distance moved from natal burrow (m)
An example of kin selection and altruism
Is the warning behavior observed in Belding’s ground squirrels
Male
Female
Age (months)
Mean distance moved from natal burrow (m)
300
200
100 2 3 4 12 13 14 15 25 26
Figure 51.35

82. 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

83. Social Learning Social learning
Forms the roots of culture
Culture can be defined as a system of information transfer through observation or teaching
That influences the behavior of individuals in a population

84. Mate Choice Copying Mate choice copying
Is a behavior in which individuals in a population copy the mate choice of others

85. This type of behavior
Has been extensively studied in the guppy Poecilia reticulata
Figure 51.36
Male guppies
with varying
degrees of
coloration
Control Sample
Female guppies prefer
males with more orange
coloration.
Experimental Sample
Female model
engaged in
courtship with
less orange
male
Female guppies prefer less
orange males that are associated
with another female.

86. Social Learning of Alarm Calls
Vervet monkeys
Produce a complex set of alarm calls

87. Infant monkeys give undiscriminating alarm calls at first
But learn to fine-tune them by the time they are adults
Figure 51.37

88. No other species
Comes close to matching the social learning and cultural transmission that occurs among humans
Figure 51.38

89. Evolution and Human Culture
Is related to evolutionary theory in the distinct discipline of sociobiology

90. Human behavior, like that of other species
Is the result of interactions between genes and environment
However, our social and cultural institutions
May provide the only feature in which there is no continuum between humans and other animals