Animals and Humans! Lee Alan Dugatkin Principles of Animal Behavior THIRD EDITION Chapter 1 Principles of Animal Behavior 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" 2014 W. W. Norton & Company, Inc. 1
Scientific Questions & Levels of Analysis! Niko Tinbergenʼs 4 Questions! 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" Definition! 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" Evolution & Natural Selection! 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" 2
Natural Selection in Field Crickets! Marlene Zuk, evolutionary biologist University of California, Riverside" Hawaiian field crickets Teleogryllus 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) that could 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 Common Mole Rats! Andrew Spinks, evolutionary biologist University 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" 3
9/14/15 Individual Learning! 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! Learning & Natural Selection in Grasshoppers! Reuven Dukas, animal cognition & behavioural ecology McMaster University, Hamilton, ON (Reuven Dukas & Elizabeth Bernay)" Studied learning-related benefits of 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)" 4
Cultural Transmission! 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! 5
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" 6
Social Learning Across Generations! Conceptual, Theoretical & Empirical Approaches! 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 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" 7
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! Scientific Method! 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" 8
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!! 9