WEEK 1 – Jan 8th and 9th 2014 Studying animal behavior

9th January 2014 Bio 335 - Animal behavior - Week 1 - Lecture 2 1

WEEK 1 – Jan 8th and 9th 2014Studying animal behavior – questions,

foundations and methodsPart 2 – Foundations of ethology

Raghav RajanBio 335 – Animal Behavior

Jan 9th 2014


BEHAVIOR

Always a case of cause-effect

Proximatemechanisms

Ultimatemechanisms

What causes the behavior? How does it change over development?Can be answered but in the lab (not natural settings

What are the effects on survival, reproductive success?Can be answered in various ways – sometimes practically difficultHow did it evolve?Difficult to answer, but we can compare across livingspecies and guess


Foundations of ethology

● Natural selection

– Any trait that provides a reproductive advantage would be favoured

● Individual learning● Cultural transmission


Natural selection example - Singing behavior of Hawaiian male crickets

● Produces sound by moving smooth scraper on one wing over the serrated file on the other wing

● Females do not mate with non-singing males


Natural selection - Singing behavior of Hawaiian male crickets

● But singing also attracts parasites – fly that lays eggs on singing cricket

● Ultimately leads to death of cricket



● Flies most prevalent on Kauai island – about 30% crickets parasitized

● With time, Zuk and colleagues heard fewer singing crickets

● Number of crickets did not change!!● Flatwing males that don't make

sound – maybe the position of the file changed

● Flatwing males hardly ever parasitized – should favor survival

● But, do they mate??



● Zuk and colleagues hypothesized that these crickets may stay near singing males and get opportunities to mate

● How to test it?● Flatwing males were more attracted to these songs● Maybe they manage to mate by staying close to singing crickets

Songs of normal male

crickets





● Individual learning

– Ability to learn can change the frequency of behaviors during a lifetime

– Natural selection may work on the ability to learn● Cultural transmission


Individual learning example – hypothetical case of a female bird mating

● Female bird could keep track of mates that produced highest number of offspring

● Could then change mating pattern accordingly● Occurs in the lifetime of an animal, but natural selection

can also select for the ability to learn


Link between natural selection and learning

● Grasshopper foraging has some learned components

● It learns to associate various cues with food sources


Learning to associate cues with various food sources

● Balanced diet (b) and deficient diet (d)● Odors, colors associated with each● Either consistent pairing (learning) or random


Learning cues associated with foraging improved fitness

● Both eventually fed more on balanced diet, but those in learning group were faster

● Higher growth rate – better fitness








– Animals learn by copying others

– New behaviors can spread through populations quickly

– Can also be transmitted across generations


Cultural transmission example – foraging in rats

● Rats – scavengers● Lots of new foods – which one is good, which one is

bad?● What is the rat equivalent of zomato?


Indeed rats can learn food preferences from other rats

● Observer rat interacts with demonstrator rat (that has eaten rat chow with cocoa)

● Observer rat now prefers demonstrators diet


Cultural transmission goes within and across generations

● Unlike individual learning that lasts only that animal's lifetime


Various approaches to ethology


Conceptual approach – inclusive fitness of an individual

● An individual's total fitness measured by genetic contribution to the next generation

● Direct – viable offspring it produces

● Indirect – viable offspring of close genetic relatives


Theoretical approach – choosing what to eat


Empirical – experimental or observational studies


Project

● Pick an animal● Observe and record in detail the behavior● Ethograms, behavior transitions, time spent in each

behavior, etc.● Make hypothesis about one of these behaviors (Tinbergen's

four questions)● Design experiments● Assignments at various stages, end semester report in the

form of a journal article – description of behavior, hypothesis, proposed experiments, predictions, discussion


Description of animal behavior

● Ethogram – a pictorial representation or description of all possible behaviors in a particular context

● Important to observe carefully and record in as unbiased a fashion as possible

– Detailed descriptions

– Descriptions of behavior as is without interpretations● Break down into simpler individual elements● Helps to quantify, to compare, etc.● Serves as a record


Sample ethogram


Time-budget analysis

● In a given period of time (say 15 min.), what is the proportion of time spent doing each of the behaviors in the ethogram

● Pie-chart, bar graphs, etc.


Sampling strategies

● Ad-libidum sampling – record as much info as possible – non-systematic

● Focal animal sampling – actions of one animal during a predetermined fixed duration (say 1 hour)

● All occurence sampling – record all occurrences of a particular behavior

● Instantaneous or scan sampling – look at behaviors of lots of animals at a given time

– You can either record the proportion of behaviors shown by one animal

– Or record the behaviors shown by a large number of animals at a given time and infer above


Sequence transitions in behavior

● What behavior follows what behavior and with what probability

WEEK 1 – Jan 8th and 9th 2014 Studying animal behavior

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