Chapter 51

1. Chapter 51 Behavioural Ecology

2. Studying behaviour • Humans have probably studied animal behaviour • for as long as we have lived on Earth • As hunters • knowledge of animal behaviour was essential to human survival

3. The modern scientific discipline of behavioural ecology • extends observations of animal behaviour by studying how such behaviour is controlled and how it develops, evolves, and contributes to survival and reproductive success

4. Concept 51.1: behavioural ecologists distinguish between proximate and ultimate causes of behaviour • The scientific questions that can be asked about behaviour can be divided into two classes • those that focus on the immediate stimulus and mechanism for the behaviour • those that explore how the behaviour contributes to survival and reproduction

5. Dorsal fin Anal fin Figure 51.2 What Is behaviour? • Behaviour • is what an animal does and how it does it • includes muscular and nonmuscular activity

6. Learning • is also considered a behavioural process

7. Proximate and Ultimate Questions • Proximate, or “how,” questions about behaviour • focus on the environmental stimuli that trigger a behaviour • focus on the genetic, physiological, and anatomical mechanisms underlying a behavioural act • e.g. How does day length influence breeding in birds? • increased day (environmental stimuli) length triggers hormone production associated with reproduction like singing & nest building

8. Ultimate, or “why,” questions about behaviour • address the evolutionary significance of a behaviour • Why did natural selection favour this type of behaviour? • Proximate & ultimate causation are linked • e.g. many animals breed during spring & summer because of warmth of seasons • abundant food supply may increase chances of offspring surviving

9. Ethology • Ethology is the scientific study of animal behaviour • particularly in natural environments • Karl von Frisch, Konrad Lorenz, & Niko Tinbergen • What are the questions that must be answered to understand any behaviour? • What is the mechanistic basis of the behaviour, including chemical, anatomical, physiological mechanisms? • How does development of an animal influence behaviour? • What is the evolutionary history of the behaviour? • How does behaviour contribute to survival & reproduction (fitness)?

10. Behaviours typically studied by ethologistsFixed Action Patterns • A fixed action pattern (FAP) • is a sequence of unlearned, innate behaviours that is unchangeable • once initiated, is usually carried to completion

11. A FAP is triggered by an external sensory stimulus • known as a sign stimulus

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

13. (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 behaviour occurs

14. Behaviour: 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 behaviour in male stickleback fish

15. Imprinting • Imprinting is a type of behaviour • that includes both learning and innate components and is generally irreversible

16. 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 behaviours can be learned • An example of imprinting is young geese • following their mother

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

18. Behaviour: 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 behaviour

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

20. Concept 51.2: Many behaviours have a strong genetic component • Biologists study the ways both genes and the environment • influence the development of behavioural phenotypes • nature-versus-nurture issue is not about whether genes or environment influence behaviour • how are both involved? • Behaviour that is developmentally fixed • is called innate behaviour and is under strong genetic influence

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

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

23. 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 • Pill bugs • become more active in dry areas and less active in humid areas

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

25. 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

26. Figure 51.8 Migration • Many features of migratory behaviour in birds • have been found to be genetically programmed

27. e.g. blackcap = warbler – range from Cape Verde Islands to N. Europe • behaviour = N. Europe populations migrate at night -CVI populations do not migrate -NE pop. exhibit migratory restlessness when held in captivity • experiment = cross German with CVI blackcaps • result = 40% of offspring show migratory restlessness • conclusion = must be under genetic control

28. Animal Signals and Communication • In behavioural ecology • a signal is a behaviour that causes a change in another animal’s behaviour • Communication • is the reception of and response to signals

29. 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

30. Chemical Communication • Many animals that communicate through odors • emit chemical substances called pheromones • common among mammals & insects • often relate to reproductive behaviour • context is important • e.g. honey bee hive • inside hive pheromones maintain social order • outside triggers mating with queen

31. (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

32. 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

33. 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

34. Genetic Influences on Mating and Parental behaviour • A variety of mammalian behaviours • are under relatively strong genetic control

35. Figure 51.11 • Research has revealed the genetic and neural basis • for the mating and parental behaviour of male prairie voles • arginine-vasopressin (AVP)

36. Concept 51.3: Environment, interacting with an animal’s genetic makeup, influences the development of behaviours • Research has revealed • that environmental conditions modify many of the same behaviours

37. Dietary Influence on Mate Choice behaviour • One example of environmental influence on behaviour • is the role of diet in mate selection by Drosophila mojavensis

38. 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

39. 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

40. Social Environment and Aggressive behaviour • Cross-fostering studies in California mice and white-footed mice • have uncovered an influence of social environment on the aggressive and parental behaviours of these mice • California mice – monogamous, highly aggressive, extensive parental care • white-footed mice – not monogamous, little parental care

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

42. Learning • Learning is the modification of behaviour • based on specific experiences • Learned behaviours • range from very simple to very complex

43. Habituation • Habituation • is a loss of responsiveness to stimuli that convey little or no information

44. Spatial Learning • Spatial learning is the modification of behaviour • based on experience with the spatial structure of the environment

45. 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.

46. Cognitive Maps • A cognitive map • is an internal representation of the spatial relationships between objects in an animal’s surroundings • how do you distinguish between animal using landmarks & one using cognitive map? • e.g. corvids – store food in caches from which bird can retrieve food later • pinyon jays & Clark’s nutcrackers store nuts in as many as thousands of caches • can relocate caches • can also keep track of food quality

47. Associative Learning • In associative learning • animals associate one feature of their environment with another

48. 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

49. Figure 51.16 • Operant conditioning is another type of associative learning • in which an animal learns to associate one of its behaviours with a reward or punishment

50. 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 • cognitiveethology – examines connection between animal’s nervous system & it’s behaviour • how animal’s brain represents objects in environment • many animals (including insects) capable of distinguishing “same” & “different” objects