Chapter 51

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. Figure 51.1 • Cranes are birds that have captivated people’s interest • Possibly because they are large and their behavior is easily observed

4. 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

5. 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

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

7. Learning • Is also considered a behavioral process

8. 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

9. Ultimate, or “why,” questions about behavior • Address the evolutionary significance of a behavior

10. Ethology • Ethology is the scientific study of animal behavior • Particularly in natural environments

11. 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

12. 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

13. A FAP is triggered by an external sensory stimulus • Known as a sign stimulus

14. (a) A male three-spined stickleback fish shows its red underside. Figure 51.3a • In male stickleback fish, the stimulus for attack behavior • Is the red underside of an intruder

15. (b) The realistic model at the top, without a red underside, produces no aggressive response in a male three-spined stickleback fish. Theother models, with red undersides, produce strong responses. Figure 51.3b • When presented with unrealistic models • As long as some red is present, the attack behavior occurs

16. 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. ULTIMATE CAUSE: By chasing away other male sticklebacks, a male decreasesthe chance that eggs laid in his nesting territory will be fertilized by another male. Figure 51.4 • Proximate and ultimate causes for the FAP attack behavior in male stickleback fish

17. Imprinting • Imprinting is a type of behavior • That includes both learning and innate components and is generally irreversible

18. 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

19. An example of imprinting is young geese • Following their mother

20. Konrad Lorenz showed that • When baby geese spent the first few hours of their life with him, they imprinted on him as their parent

21. 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. Figure 51.5 • There are proximate and ultimate causes for this type of behavior

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

23. 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

24. Directed Movements • Many animal movements • Are under substantial genetic influence • These types of movements • Are called directed movements

25. Kinesis • A kinesis • Is a simple change in activity or turning rate in response to a stimulus

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

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

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

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

30. 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

31. 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

32. Chemical Communication • Many animals that communicate through odors • Emit chemical substances called pheromones

33. (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 thebottom of the aquarium and reduce their movement. Figure 51.9a, b • 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

34. Volley period 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 SONOGRAMSChrysoperla plorabunda parent Vibration volleys Standard repeating unit crossed with Chrysoperla johnsoni parent Volley period Standard repeating unit 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. Auditory Communication • Experiments with various insects • Have shown that courtship songs are under genetic control

35. F1 hybrids, typical phenotype Volley period 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

36. Genetic Influences on Mating and Parental Behavior • A variety of mammalian behaviors • Are under relatively strong genetic control

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

38. 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

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

40. EXPERIMENT 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. 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). With Baja males 100 (a) With Sonoran males 75 (b) Proportion of matings by Sonoran females 50 25 0 Agria cactus Artificial Organ pipe cactus Culture medium 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. Figure 51.12 • Laboratory experiments have demonstrated • That the type of food eaten during larval development influences later mate choice in females

41. Figure 51.13 • 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

42. 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

43. Table 51.1 • Influence of cross-fostering on male mice

44. Learning • Learning is the modification of behavior • Based on specific experiences • Learned behaviors • Range from very simple to very complex

45. Habituation • Habituation • Is a loss of responsiveness to stimuli that convey little or no information

46. Spatial Learning • Spatial learning is the modification of behavior • Based on experience with the spatial structure of the environment

47. 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 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 Nest No Nest Nest The experiment supported the hypothesis that digger wasps use landmarks to keep track of their nests. CONCLUSION Figure 51.14 • In a classic experiment, Niko Tinbergen • Showed how digger wasps use landmarks to find the entrances to their nests After the mother visited the nest and flew away, Tinbergen moved the pinecones a few feet to one side of the nest.

48. Cognitive Maps • A cognitive map • Is an internal representation of the spatial relationships between objects in an animal’s surroundings

49. Associative Learning • In associative learning • Animals associate one feature of their environment with another

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