CLASSIC CONCEPTS IN BEHAVIOR 37 1 Behavioral biologists

CLASSIC CONCEPTS IN BEHAVIOR 37. 1 Behavioral biologists study the actions of animals in their natural environments • Behavioral biology is the study of what animals do when interacting with their environment • Behavior can be interpreted in terms of proximate causes (immediate interaction with the environment) or ultimate causes (evolutionary differences)

• Early insights into the nature of behavior came from studies by Nobel laureates Karl von Frisch, Konrad Lorenz, and Niko Tinbergen • They were among the first experimentalists in behavioral biology • Tinbergen and Lorenz performed experimental studies of innate behavior and simple forms of learning

• A classic Tinbergen experiment deals with the nesting behavior of the digger wasp – The female wasp often excavates and cares for four or five separate nests • Tinbergen used this experiment to test his prediction that digger wasps use landmarks to keep track of the location of their nests

• In the experiment, Tinbergen placed a circle of pinecones around a nest opening Nest 1 Figure 37. 1, Part 1

• After the female flew away, Tinbergen moved the pinecones a few feet to one side of the nest opening – When the female wasp returned, she flew to the middle of the circle of pinecones rather than to the actual nest opening Nest 2 No Nest Figure 37. 1, Part 2

• Tinbergen next arranged the pinecones in a triangle around the nest and made a circle of small stones off to one side of the nest opening – This time the wasp flew to the stones Nest 3 No Nest Figure 37. 1, Part 3

• The wasp cued in on the arrangement of the landmarks rather than the landmarks themselves • This experiment demonstrated that the wasp did use landmarks and that she could learn new ones to keep track of her nest

• Behavioral ecologists are especially interested in the ultimate causes of behavior, which are evolutionary Natural selection preserves behaviors that enhance fitness

37. 2 Behavior results from both genes and environmental factors • Animal behavior often involves a combination of genetic programming (innate behavior) and environmental experiences (learning) both genes and the environment influence the development of behavioral phenotypes- just like any other traits

• The gathering of nest materials by lovebirds has genetic and environmental components Single long strip carried in beak (Fischer’s lovebird) Several short strips tucked under feathers (peach-faced lovebird) Tucking failure Strip in beak Hybrid behavior Figure 37. 2

37. 3 Innate behavior often appears as fixed action patterns • Sign stimuli (often a simple cue in an animal’s environment) trigger innate, essentially unchangeable fixed action patterns (FAPs) • The genetic programming underlying FAPs ensures that such activities are performed correctly without practice

• The graylag goose always retrieves an egg that has been bumped out of her nest in the same manner – This is a fixed action pattern – She carries this sequence to completion, even if the egg slips away during the process Figure 37. 3 A

• Several key events in the life cycle of the European cuckoo are determined by fixed action patterns – Egg-laying behavior 1 2 3 Figure 37. 3 B

– The behavior of the cuckoo hatchling ejecting the host eggs from the nest – The feeding behavior of a foster mother to the cuckoo chick Figure 37. 3 B

37. 4 Learning ranges from simple behavioral changes to complex problem solving • Learning is a change in behavior resulting from experience • Habituation is one of the simplest forms of learning – An animal learns not to respond to a repeated stimulus that conveys little or no information – For example, birds eventually become habituated to scarecrows and no longer avoid nearby fruit trees

Table 37. 4

37. 5 Imprinting is learning that involves both innate behavior and experience • Imprinting is irreversible learning limited to a sensitive period in an animal's life; it enhances fitness by enabling rapid learning • Example: Lorenz used the graylag goose to demonstrate imprinting. He took over the maternal role for a group of goslings

• Not all examples of imprinting involve parentoffspring bonding – Although newly hatched salmon do not receive any parental care, they imprint on the complex mixture of odors unique to the freshwater stream where they hatch – This allows salmon to find their way back to the stream to spawn after spending a year or more at sea

• Imprinting plays an important role in song development for many kinds of birds Figure 37. 5 B

37. 6 Many animals learn by association and imitation • Associative learning is learning that a particular stimulus or response is linked to a reward or punishment – These ducks have learned to associate humans with food handouts – They congregate rapidly whenever a person approaches the shoreline Figure 37. 6 A

• Trial-and-error learning is a common form of associative learning – An animal learns to associate one of its own behavioral acts with a positive or negative effect Figure 37. 6 B

• Imitation is learning by observing and mimicking the behavior of others – This form of learning is not limited to a sensitive period – Many predators, including cats and coyotes, seem to learn some of their basic hunting tactics by observing and imitating their mother

37. 7 Animal cognition includes problem-solving behavior • Some animals exhibit problemsolving behavior – Examples: chimpanzees and ravens Figure 37. 7 A, B

ECOLOGICAL ROLES OF BEHAVIOR 37. 8 An animal's behavior reflects its evolution • Behavior is an evolutionary adaptation that enhances survival and reproductive success • Behavior evolves as natural selection finetunes an animal to its environment – The hunting and reproduction behaviors of jaguars – Nest location by digger wasps – Imprinting of goslings

37. 9 Biological rhythms synchronize behavior with the environment • Animals exhibit a great variety of rhythmic behavior patterns • Circadian rhythms are patterns that are repeated daily – Sleep/wake cycles in animals and plants • Circadian rhythms appear to be timed by an internal biological clock

• In the absence of environmental cues, these rhythms continue – But they become out of phase with the environment 12: 12 (natural) Constant darkness Figure 37. 9 A

37. 10 Animal movement may be oriented to stimuli or landmarks • Movement in a directed way enables animals to – avoid predators – migrate to a more favorable environment – obtain food – find mates and nest sites

TYPES of ANIMAL MOVEMENT 1. kinesis- simplest type of animal movement random movement in response to a stimulus 2. taxis- another simple type – A more or less automatic movement directed toward or away from some stimulus – Examples include rheotaxis (current) chemotaxis, and phototaxis 3. Some animals use landmarks to find their way within an area

37. 11 Movement from place to place often depends on internal maps • Many animals formulate cognitive maps – Internal representations of spatial relationships among objects in their surroundings (wasp example) • Some animals undertake long-range migrations – Examples: whales, sea turtles, birds, monarch butterflies • Animals navigate using the sun, stars, temperature gradients, landmarks, or Earth's magnetism

• Migrating gray whales use coastal landmarks to stay on course Arctic Ocean FEEDING GROUNDS Siberia Alaska NORTH AMERICA Pacific Ocean Atlantic Ocean Baja California BREEDING GROUNDS Figure 37. 11 A

• The indigo bunting learns a star map and navigates by fixing on the North Star Paper Ink pad Funnelshaped cage Figure 37. 11 B

37. 12 Behavioral ecologists use cost/benefit analysis in studying feeding behavior • Animals are generally selective and efficient in their food choices – Some animals, such as gulls, are feeding “generalists” – Other animals, such as koalas, are feeding “specialists” Figure 37. 12 A, B

• The mechanism that enables an animal to find particular foods efficiently is called a search image • Natural selection seems to have shaped feeding behavior to maximize energy gain and minimize the expenditure of time and energy – This is theory of optimal foraging

• Whenever an animal has food choices, there a number of tradeoffs – A bass can get more usable energy from minnows, but crayfish are easier to catch – However, it may take more time to eat a crayfish because of its tough exoskeleton Figure 37. 12 C

• The kangaroo rat selects high-energy foods (seeds) in a manner that reduces time spent above the ground, where it is exposed to predators Figure 37. 12 E

SOCIAL BEHAVIOR AND SOCIOBIOLOGY 37. 13 Sociobiology places social behavior in an evolutionary context • Social behavior is defined as the interaction among members of a population • The discipline of sociobiology studies social behavior in the context of evolution

37. 14 Rituals involving agonistic behavior often resolve confrontations between competitors • Agonistic behavior is social behavior consisting of threats and combat that settles disputes between individuals in a population • Agonistic behavior can directly affect an individual's evolutionary fitness – The victor often gains first or exclusive access to mates Figure 37. 14

37. 15 Dominance hierarchies are maintained by agonistic behavior • Many animals live in social groups maintained by agonistic behaviors • Dominance hierarchy is the ranking of individuals based on social interactions

• Chickens establish a “peck order” • Resources are often partitioned based upon the dominance hierarchy Figure 37. 15

37. 17 Territorial behavior parcels space and resources • Humans tend to space themselves out when they are close to others – They establish what we might call personal territories Figure 37. 17 A

• Many animals exhibit territorial behavior – It is a form of social behavior that partitions resources

• A territory is an area that individuals defend and from which other members of the same species are usually excluded – The size of the territory varies with species, the function, and the available resources – Territories are typically used for feeding, mating, and/or rearing young

• Territoriality is often maintained by agonistic behavior – These New Zealand gannets maintain their individual nesting territories by calling and pecking at each other Figure 37. 17 B

• Territoriality can enhance fitness if the benefits of possessing a territory outweigh the energy costs of defending one

• Territorial rights are proclaimed continually in a variety of ways – Bird songs – Noises, such as the bellowing of sea lions and the chattering of squirrels – Defecation in open areas – Scent markers, such as urine Figure 37. 17 C