Animal behavior

Chapter 51

keywords

• Fixed action pattern, Sign stimulus
• proximate and ultimate causes of behavior
• imprinting
• sociobiology
• sexual selection
• altruism
• kin selection

How do animals work - meeting functional demands

• Body plans and structure
• physiological mechanisms
• behavior

Causes for behavior

• "proximate" - environmental stimuli that trigger behavior, e.g., day length, visual stimuli
• "ultimate" - why does stimulus trigger behavior - generally believed to be due to natural selection (adaptive behavior)

Behavior results from both genes AND environment

• Whether an animal CAN exhibit a particular behavior is determined by genes
• Whether an animal DOES exhibit this behavior can be dependent on environment.
• An animal may not exhibit a possible behavior in certain environments

Figure 51.1 Genetic and environmental components of behavior: a case study

Lovebird study

• Genetic component - illustrated by intermediate strips and tucking behavior in hybrid
• Environmental component - illustrated by loss of ineffective tucking behavior by hybrids in later seasons.

Fixed action pattern

• Sequence of behavioral acts that is unchangeable and usually carried to completion once initiated
• Fixed action pattern is stimulated by a sign stimulus
• many animals only use a relatively small subset of sensory information to trigger behavior, humans are more complex

Figure 51.2 Niko Tinbergenís experiments on the digger waspís nest-locating behavior

Digger wasp study

• Fixed action pattern is cueing on visual landmarks to locate nest
• sign stimulus is pattern of landmarks around nest

Figure 51.3 Classic demonstration of innate behavior

Stickleback study

• Fixed action pattern = aggression twards other "males"
• sign stimulus = red belly

Figure 51.4 Mayflies laying eggs on human-made surfaces

Figure 51.5 The repertoire of a songbird

Why is there multisong behavior?

• Warning off enemies, attracting mates?

Attracting mates?

• What does song repertoire have to do with being a good mate?
• Postulate that repertoire increases fitness by making older more experienced males more attractive to females.
• Testable hypotheses:
• males learn more song types as they get older
• felames prefer males with large repertoires

Figure 51.6 Female warblers prefer males with large song repertoires

Learning

• Experience based modification of behavior

Figure 51.8 Vervet monkeys learn correct use of alarm calls

Vervet monkey alarm calls

• Different alarm calls for leopards, eagles, snakes
• Infant monkeys give indiscrimate alarm calls but eventually learn to give the right call at the appropriate time

Imprinting

• A type of learning that is limited to a sensitive period of an animals life and is generally irreversible
• Work of Konrad Lorenz (nobel prize 1973)
• great book to read: King Solomonís Ring

Figure 51.9x Geese imprinting

Imprinting in goose hatchlings

• Bonding occurs after hatching
• imprint of "mother"
• important for eliciting care, developing species identity
• during sensitive period can be experimentally imprinted on the wrong mother.

Figure 51.9 Imprinting: Konrad Lorenz with imprinted geese

Associative learning

• Classical conditioning - Pavlovís dogs, arbitrary stimulus related to reward or punishment
• Operant conditioning - trial and error learning, learn to associate own behavior to reward or punishment

Figure 51.11 Operant conditioning

Figure 51.12 Play behavior: Cheetahs and polar bears

Figure 51.13 Raven problem solving

Figure 51.13x Chimps making tools

Social behavior

• Interaction between two or more animals usually of the same species
• sociobiology - applies evolutionary theory to interpretation of social behavior

Figure 51.18 Cooperative prey capture

Figure 51.19 Ritual wrestling by rattlesnakes

Figure 51.20 Reconciliation in chimpanzees

Figure 51.21 Territories: gannets nesting

Figure 51.22 Staking out territory with chemical markers

Figure 51.x2 Territoriality: mountain goats and stallions

Figure 51.23 Courtship behavior in the three-spined stickleback

• Possible benefit?
• Identify mates of the same species
• establish mate as ready to reproduce
• sexual selection
• importance of parental investment

Figure 51.24 Male stalk-eyed fly

• Inability to develop long eyestalks may be correlated with certain genetic disorders

Communication

• Pheromones
• chemical trails
• honeybee "dancing"

Figure 51.26 Fire ants following a pheromone trail

Figure 51.27 Communication in bees: one hypothesis

Altruistic behavior

• Behavior that does not immediately benefit the individual

Figure 51.28 Altruistic behavior in the Belding ground squirrel

• Giving alarm call increases chance of getting killed

Figure 51.30 The coefficient of relatedness between siblings is 0.5

Kin selection

• Increasing reproductive success of relatives
• can be a cause of altruistic behavior
• Female ground squirrels make more alarm calls than males. Why?

Figure 51.31 Kin selection and altruism in the Belding ground squirrel