ANIMAL BEHAVIOR 1. Proximate vs. Ultimate Causes

1. Figure 51.1 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

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. Dorsal fin Anal fin 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

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. Nat. Sel. Environmental Stimuli Gene Pool ORGANISMS 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) A male three-spined stickleback fish shows its red underside. Figure 51.3a • 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

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

13. 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 decreases the chance that eggs laid in his nesting territory will be fertilized by another male. • Proximate and ultimate causes for the FAP attack behavior in male stickleback fish

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

15. Moist site under leaf Dry open area Kinesis increases the chance that a sow bug will encounter and stay in a moist environment—improves gas exchange, chances of finding food • 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)

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

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

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. (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 • 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)

21. Volley period 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 SONOGRAMSChrysoperla plorabunda parent 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. Standard repeating unit Vibration volleys crossed with Chrysoperla johnsoni parent Volley period Standard repeating unit Auditory Communication • Experiments with various insects have shown that courtship songs are under genetic control Results: song similar to one species but interval between each song similar to the other

22. Figure 51.11 • 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. 1135 for more details)

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. 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 With Sonoran males 100 75 Proportion of matings by Sonoran females 50 Artificial 25 Agria cactus Culture medium 0 Organ pipe cactus Figure 51.12 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. 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. 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

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

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. 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.

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. Figure 51.16 • Operant conditioning is another type of associative learning in which an animal learns to associate one of its behaviors with a reward or punishment 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. Figure 51.17 • Problem solving can be learned by observing the behavior of other animals (= social learning)

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. (a) A garter snake (Thamnophis elegans) (b) A banana slug (Ariolimuscalifornicus); not to scale Figure 51.18a, b 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

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. 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. 125 60 50 100 40 Average number of drops 75 30 Total flight height Average number of drops 20 Drop height preferredby crows 50 10 0 25 2 3 5 7 15 • 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 Total flight height (number of drops  drop height) Height of drop (m)

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

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