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Chapter 1 Principles of Animal Behavior

© 2014 W. W. Norton & Company, Inc.

Lee Alan Dugatkin

Principles of Animal Behavior

THIRD EDITION

•  We are surrounded by animals and many humans like to know them"

•  Early human art depicts animal behaviour"•  Earliest humans depended on animals"•  Ethology: the scientific study of animal

behaviour"

Animals and Humans!

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•  Ethologists pose 4 distinct types of research questions in the scientific study of animal behaviour"

•  Animal behaviour classic paper

Niko Tinbergen (1963) On the aims and methods of ethology. Zeitschrift fur Tierpsychologie 20:410-440"

Scientific Questions & Levels of Analysis! Niko Tinbergenʼs 4 Questions!

•  Behaviour: the internally coordinated, externally visible response of whole living organisms to internal and/or external stimuli"

•  Externally visible = can be observed & measured"•  e.g. ectotherms, move to cooler locations as their

body temperature rises"

Definition!

•  In 1859, Charles Darwin published his classic book “On The Origin of Species”"

•  Arguments were laid for how evolutionary change has shaped the diversity of life through the process of natural selection!

•  Natural selection: the process whereby traits that are heritable and confer the highest relative reproductive success increase in frequency over many generations"

•  Studied from ultimate & proximate prospectives"

Evolution & Natural Selection!

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•  Marlene Zuk, evolutionarybiologistUniversity of California, Riverside"

•  Hawaiian field cricketsTeleogryllus oceanicus"

•  Males sing to attract females"•  Both benefits and costs to song"•  Benefit: attracts females for mating"•  Cost: attracts parasitoid flies (Ormia ochracea)"

Natural Selection in Field Crickets!

•  Kauai male field crickets had modified wings (flat wings) thatcould not produce much song"

•  Survival advantage for flat wing males, but how do they mate?"

•  Satellite male mating strategy"•  Experiment: flatwing wings were more strongly

attracted to playbacks of normal male song, suggesting the evolution of new mating strategy"

Natural Selection in Field Crickets!

•  Andrew Spinks, evolutionarybiologistUniversity of Cape Town, South Africa"

•  Xenophobia in the common mole rat,Cryptomys hottentotus"

•  Xenophobia: fear of strangers"•  Hypothesized xenophobia will be strong when

resources are scarce b/c of intense competition"•  Aggression trials in 2 populations from arid (dry)

& mesic (moist) environments"

Natural Selection in Common Mole Rats!

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•  Individual learning: a process that can alter the frequency of behaviours displayed within the lifetime of an individual organism"

•  Proximate perspective: how learning affects behaviour over the lifetime of an organism"

•  Ultimate perspective: how natural selection affects the learning abilities of an organism!

Individual Learning!

Learning & Natural Selection in Grasshoppers!

•  Reuven Dukas, animal cognition & behavioural ecologyMcMaster University, Hamilton, ON (Reuven Dukas & Elizabeth Bernay)"

•  Studied learning-related benefitsof foraging in the American grasshopper,Schistocerca americana"

•  Laboratory feeding trials using “balanced” & “deficient” diets"

•  Diets paired with flavour (odor) & colored cards (i.e. cues providing learning opportunities)"

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•  A process that can alter type and frequency of behaviours displayed by an organism"

•  Refers to situations where animals learn something by copying the behaviour of others"

•  AKA: social learning!•  Proximate perspective: how social learning

affects behaviour over the lifetime"•  Ultimate perspective: how natural selection

affects social learning abilities over generations!

Cultural Transmission!

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Social Learning in Norway Rats!

•  Jeff Galef, animal cognition & one of the “fathers” of social learning McMaster University, Hamilton, ON"

•  Social learning & foraging in the Norway / common / brown / sewer rat,Rattus norvegicus"

•  Scavenging foraging has costs (danger) & benefits (bounty)"

•  Information-center hypothesis: foragers learn critical information about location/identity of foods by interacting with recent foragers"

Social Learning in Norway Rats!

•  Information-center hypothesis: foragers learn critical information about location/identity of foods by interacting with recent foragers"

•  Rats were divided into 2 groups: observers & demonstrators (tutors)"

•  Question: can observer rats learn about novel foods by interacting with demonstrators (tutors)?"

•  Observers & demonstrators housed together. Then tutors isolated and fed novel diet with distinct flavor/odor"

•  Tutors returned to home cage, interact with observers for 15 min"

•  Observers isolated & tested for food preferences 48 hrs"

Social Learning Across Generations!

•  Unlike individual learning, social learning can occur both within and between (across) multiple generations"

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Social Learning Across Generations!

•  Unlike individual learning, social learning can occur both within and between (i.e. across) multiple generations"

•  Natural selection can act on the tendency to copy the behaviour of others (e.g. conspecifics)"

Conceptual, Theoretical & Empirical Approaches!

Conceptual Approaches!

•  Conceptual approaches involve formulating & integrating unconnected ideas in new ways and can lead to new experimental work"

•  Example: kin selection (William D. Hamilton)""Considered to be one of THE most important conceptual breakthroughs in animal behaviour"

Kin Selection (W. D. Hamilton, 1964)!

•  Kin selection: natural selection favours behaviours that increase the reproductive success of individuals that express the behaviour AND the close genetic relatives (i.e. kin) that also express the behaviour"

•  Fitness consists of direct & indirect components"•  Direct fitness: # viable offspring produced by IND + any

effects IND has on direct descendents of its own offspring"•  Indirect fitness: increased reproductive success of INDʼs

genetic relatives (excluding offspring & direct descendants of own offspring) due to the behaviour of IND"

•  Inclusive fitness: direct fitness + indirect fitness"

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Theoretical Approaches!

•  Theorectical approaches involve formulating explicit mathematical models of the world"

•  Example: optimal foraging theory (Stevens and Krebs, 1986)"

•  Optimality theory: searches for best (optimal) solution to a problem given certain constraints"

•  Solving for different parameter values in a model leads to testable (and often counterintuitive) predictions in animal behaviour"

•  Goal: obtain a model that distils complex behaviour to general essentials with clear, testable predictions (models are not meant to mimic natural world)"

Empirical Approaches!

•  Empirical approaches involve gathering data about the world and drawing conclusions from that evidence"

•  Consists of 2 basic types of research:"•  Observational studies: watching and recording

without attempting to manipulate system; used to infer correlation but not causation"

•  Experimental studies: manipulating a system by changing one variable and holding all others constant; can be used to examine causality"

Scientific Method!

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Scientific Method!

•  Formulate a research question based on observations or literature review"

•  Generate a research hypothesis based on observations/what is known from literature"

•  Make new observational studies, or better yet"•  Design an experiment using a paradigm and

research methods appropriate for the question

Be sure to include carefully designed control conditions in your experiments!!