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Behavioural Ecology

Revision

WHAT IS ANIMAL BEHAVIOUR
Own Survival

Survival of Species

Own metabolism, growth/
ontogenesis movement,
locomotion, single
perception & adaptability
...
nervous
system, sense organs,
locomotion & body wall &
the shell

Reproduction, adaptability
& evolution
↓
Reproduction &
ontogenesis

Levi's et al (2009):
“The internally coordinated responses of whole
living organisms to internal &/or external stimuli,
excluding responses more easily understood as
developmental changes
...
Research included:
- Herring gull behaviour
- Stickleback breeding behaviour
- Orientation in insects
- Described several concepts: supernormal & sign
stimuli, fixed action patterns & landmark
navigation
Asked four questions about behaviour:
What is CAUSE of behaviour?
How does behaviour DEVELOP?
How has behaviour EVOLVED?
What is behaviours FUNCTION?

-

- Different ways of looking at behaviour
- Recognises necessity to understand differences
- Allows recognition of gaps in understanding
E
...
Bird song:

The Ethogram
“Inventory costs” of animal behaviour, precociously
& objectively describing: all the behaviours that a
species may undertake during its lifetime or specific
to one state”
- Mutually exclusive
- Avoid assumptions
- Use empirical descriptions
- Avoid anthropomorphism
- Save time
- Multiple observer studies
- Inflexible if behaviours more varied than
preliminary observations
- Use diagrams & take photographs/video
- Useful for scan & behaviour sampling
HOW TO MEASURE BEHAVIOUR
Quantification:

- Frequency: Number of occurrence of behaviour
within a specified time period

- Duration: Length of time which the behaviour
lasts

- Latency: Time elapsed between specified event
& next performance

- Intensity: Degree which behaviour is performed
Variables
Sunlight intensity/time of day
Visibility/depth of water
Vegetation cover
Availability of prey
Kinds of prey
Hunting success
Competition

-

Sources of Error

- Error of Apprehending - Disturbed field of view
- Observer Effect - Precession of observer
- Observer Bias - Expectation influences data
collection

- Error of Recording - Wrong method or
performance

- Computational Error - Mistakes in statistical
analysis

- Cause - Mechanism: syrinx/muscles,
-

neuroendocrine control & stimuli: light/
temperature
Development - Learned behaviour
Evolution - How did singing arise historically?
Function - Attraction of mate, territorial/warning
song & species identifier

Describing Behaviour - Behavioural Categories
Maintenance (feeding, drinking, grooming)
Social (allogrooming, dominance displays)
Reproductive (courtship & mating)
Parental (maternal/paternal behaviours)
Neonatal (behaviours in juveniles)
Play (fun, learning)
Abnormal behaviour

-

How will you find out which one?

- Observe
- When an action stops & another starts - Preagreed definitions (multiple observers)

Methods of Observation

- Sampling rules - Which subject to observe
- Recording rues - When to make observations
As libitum Sampling
No restraints on what or when
Record what is visible & relevant
Strength - Familiarise with your animals
Weakness - Bias towards conspicuous animals

-

Focal Sampling

- Observing single unit & recording all behaviours
- Dealing with complexity e
...
Large social groups
Scan Sampling
Whole group scanned at regular intervals
Strength - Large groups can be observed
Weakness - Few behaviours can be checked
Focal & scan sampling can be combined

-

Behavioural Ecology
Behaviour Sampling
Specific type of behaviour targeted
Whole group observed for behaviour
Detailed observation
Strength - Target behaviour intensively observed
Weakness - Other behaviours ignored

-

Revision
REPRODUCTIVE BEHAVIOUR
Sociobiology

Sequence Sampling
Complex order of behaviours observed
Completeness of sequence is focus parameter
Strength - Target behaviour intensively observed
Weakness - Other behaviours ignored

-

Continuous Recording:

- Produce exact record of behaviour
- Record frequency & duration of behaviours
Time Recording:

- Periodic observations
- Documenting presence or absence of behaviour:
- Instantaneous Recording
- Behaviour pattern scored according to
-

whether it occurs on each sample point
One-Zero Recording
- Behaviour pattern scored according to
whether it occurs during the interval

Methods of Observation
- Write it down
- Dictaphone, then transformation into Excel
- Video observation
- Software based techniques (Data tracking,
sequence analyses)
Activity
Movement
GPS-tracker
Transmitted: internal or external
RFID systems (radio-frequency-identfication)

-

Standard Tests
Open Field → Fear, spatial exploration
Holeboard → Fear, cognitive abilities
Elevated Plus Maze → Fear
Y-Maze → Preferences, difficult decisions
T-Maze → Preference, easy decisions
Radial-Maze → Cognitive abilities
Water-Maze → Cognitive & coordinative abilities
Rotarod → Coordinative abilities
Skinner-Box → Cognitive abilities
Novel Object → Fear

-

Choosing Species

- Can you find it? - Visibility, numbers, ethics &
permits

- Is it tolerant to humans? - Handling, husbandry,
-

stress, health & ethics
Life history - Timescale of study, complexity
Prior knowledge literature - Genetics, behaviour
Suitability - Can you answer question?
Relevance Comparability - Applicability, wider
extrapolation

- Elimination of damages due to mutation
- New combination of features
- Coevolution with predators & parasites
- Spermatogenesis - Spermatozoa produced from
male germ cells by mitosis & meiosis

- More germ cells - produced throughout life,
-

high number of descendants & low costs for
courtship & paternal care
Oogenesis - Ovum produced from female germ
cells by mitosis & meiosis
- Limited number of germ cells at birth, energyconsuming process, additional costs of
lactation & maternal care, vigorous
descendants & low costs for maternal care

Ways of life:
Solitary
- Only maternal care
- No investments of male
- Some support by older daughters
- Adaptations on morphology, ingestion
- Environmental conditions (predictable food
availability)
- Home range of males larger
- Frequent
- Mate guarding
- e
...
Female has small territory or migrating
Social:
- Maternal & paternal care
- Support older young (maternal/paternal)
- Cooperative breeding
- Closed communities
- Senses & signals for individual recognition
- Closed groups within large groups
- Reproductive suppression of group members
- Kin selection
- Frequent in conditions with limited food available
- e
...
Females social, migrate in large home
range, male meets herd daily/only sometimes
Eusocial
- Cooperative breeding
- Community help without becoming parent
- 2+ overlapping generations

Behavioural Ecology

- Development of senses & signals for individual
-

recognition
Reproductive suppression of group members
Kin selection
In conditions with limited food availability
Polyethism: specialisation in different members
of a colony leading to division of labour Morpological adaption or change of labour in
different ages

Social organisation of a honey bee colony:
- Queen - Lays eggs
- Worker - Take care of larvae, build/clean nest &
forage
- Drone - Leave nest to mate then bee

Revision
Polyandry
Fertility Insurance Hypothesis
- e
...
Redwing blackbirds, eggs of multiple mated
females more likely to hatch than monogamous
females
- e
...
Gunnison‟s prairie dogs, polyandrous
females become pregnant 100% of time &
monogamous 92%
Good Genes Hypothesis

- Females who mate with more than one male
-

Obligate:

- For period of time (copulating partner)
- Permanent: eusocial groups

Facultative:
- Without special function (pelican, jackal)
- With special function (lion, orca, chimpanzees)
Explanation for Cooperation:
- Kin selection
- Learning & experience, benefit for own
descendants
- Defensive behaviour, reduction of aggression
mating systems
Monogamy (n=2)
1
...
g
...
Females widely dispersed, remain receptive
after copulation & use other males‟ sperm →
Mate guarding hypothesis e
...
Clown shrimp
3
...
g
...
g
...
Increases
clutch survival & number of offspring
...
Resource Defence Polygyny - Few males
monopolise access to females, males compete
to control a resource females need
...
g
...
Female Defence Polygyny - Few males
monopolise access to females, males compete
to control access to females e
...
Bighorn sheep
females aggregate for defence
...
Male Dominance Polygyny - Few males
monopolise access to females, males compete
to establish dominance & allow female mate
choice e
...
Hammer-headed bat form leks at
lakesides & white-bearded manakin maintain
forest clearings

have more genetic variability in offspring & more
surviving, sperm competition important in males
e
...
Yellow-toothed cavy
e
...
Marsupial mouse, offspring of polyandrous
females grow 10% faster & 3x more survive to
weaning

More Resources (Material Benefits) Hypothesis

- e
...
Redwing blackbird females who mated with
additional males fed at their feeders

- e
...
Male Utetheisa moths provide toxic
-

defences with spermatophores, more matings
allows females to better protect eggs
e
...
Confusing paternity in African wild dogs
facilitates multi-male parental care

Infanticide Reduction Hypothesis

- Confusing paternity prevents males killing
offspring

- e
...
Hanuman langur & african lion
Promiscuity

- Costs of promiscuity: Time & Energy “Domestic
abuse”

- Good alternative in low survival of parents
- High individual numbers in short time
- Special behaviours: communal nesting
Natural Selection - Survival of the fittest, those
animals have highest reproductive
Human Selection/Breeding - Men decide desired
characteristics, only low influence by survival &
vitality
Sexual Selection- Mate choice of females,
characteristics remain selected by females
Bateman‘s Principle

- Partner is choosing, who invests more in the
descendants (usually females)

- e
...
Cricket singing - stridulation
Hypotheses

- Runaway process (Fisher 1930)
- Selection of fitness-indicating feature became

-

a problem in changing environment & lead to
extinction
- e
...
Irish Elk, saber-tooth tiger
Handicap Principle (Zahavi, 1975):
- Female prefer males with handicapping trait,
male has high variability to survive with
handicap
- Genes of several males are fixed

Behavioural Ecology

- Good genes (Hamilton & Zuk, 1982):
- Predicts substantial additive heritability for
viability genes

- Genes for resistance might have important
effects on fitness

- Coadaptation of host & parasite - Continuous
-

changing source of variability
Short-term changes of females
Adaptation of population on current demands
Depends on disease exposure
Copulation with healthy male means low
infection risk for female

Revision
PARENTAL CARE
Parental Care/Investment

- Investment in offspring that increases chances
-

-

Theory of Fluctuating Asymmetry:

- Information about stress individual experienced
- Genomic & environmental changes can cause
increase

- e
...
Environmental perturbations (temperature,
-

food availability, exposure to pollutants,
parasites)
Negative association between fluctuating
asymmetry & heterozygosity (e
...
fish)
Good concordance of finding from lab & field
e
...
Humans (success & beauty)
Link to epigenetic studies

of survival & reproduction at the expense of
parents’ ability to invest in other offspring
Direct Costs:
- Increased demand for energy & nutrients
(protein & calcium)
- Organ remodelling
Indirect Costs:
- Optional compensatory costs
- Thermoregulatory demands
- Physical activity
- Immune system
- Hyperthermia
- Disruption of sleep patterns
- Bone loss
- Oxidative stress

Animal Kingdom

- Invertebrates - Little parental care, if female only
- Fish - Paternal care most frequent, biparental
often, little maternal care

- Amphibians - Maternal & paternal equally
distributed, biparental only a few

Intrasexual Competition
- Where unsuccessful males have opportunity to
become successful, should remain close until
get an opportunity (eg
...

- Dominance hierarchies become established
...

- Rank correlates with reproductive output e
...

hyenas
- Cost of maintaining high rank includes
masculinisation & risk of reproductive
complications
- e
...
Baboons, males fight more readily to
improve social standing, time at the top is short,
competition is fierce, 4x more likely to sustain
injury than females
...


- R-Strategy
- Abundance of offspring
- Little in parental care
- Short maturation time, many offspring very

Alternatives to Fighting:
- Sneaky mating:
- e
...
Male baboons fail to control fertile
females as completely as expected
...

- Cheating the hierarchy:
- e
...
Red deer stags achieve 100% paternity if
hold females for >6 days
...

- e
...
Yellow baboons, low ranking baboons
team up to separate dominant males from
receptive females, >60% of cases
...
g
...


- K-Strategy
- Parental care
- Few offspring, effort at being good parents
- Young are altricial (can’t survive on their own
until adulthood)

- Long life span, produce few offspring - Low
mortality rates

- e
...
elephants, apes and whales, humans
Sibling Rivalry

- Trivers - Benefit/cost ratio to parent(s)
- Any offspring more interested in its survival
more than its siblings’

- Siblings benefit vs
...
5 (rsiblings = 0
...
g
...
g
...
Sibling A kills B directly (obligate, 2 eggs, e
...

eagles, boobies)
2
...
g
...
water reservoir)
Females & males mature 10-15
Mating season: April to June
Nest construction: June
Nesting material: Sediment, plants
Clutch size: 32-46 eggs
Incubation: 2 months
Risk for young:
- Predators (raccoons, birds, otters & fish)
- Flooding of nest
- Survival ratio for 1st year: 25%
- Survival ratio until maturation: 10%

-

e
...
Beaver

- Burrow - Thermoregulation, several entrances
- Different chambers of older & younger pups
- Food storage for winter
e
...
Emperor Penguin

Siblicide in the Galapagos Sea Lion
Food availability varies with season & years
Females have 1 pup, weaning up to 3 years!
23% of pups born & older sibling being nursed
Younger pup dies within 1 month (starvation,
direct attack)
- Mother sometimes intervenes

-

Hatching Asynchrony

- Single clutch hatches simultaneously or
-

sequentially
Development starts with onset of incubation
Incubation doesn’t begin until last egg laid
Altricial & semialtricial species - Hatching
asynchrony gives first chicks head start at
attracting parental attention
Order allows maximum raising of chicks based
on current resources (Amount not predictable
when eggs where laid)
Smallest chicks die due to starvation
e
...
Gulls & raptors, herons & egrets
Obligate siblicide - 2nd egg serves as insurance
against loss of first egg from infertility, predation,
or damage

Parental Favouritism

- Likely occurs when resources are variable &
adults have more young than can raise

- Females invest in eggs differently (choose sex)
- Young fed preferentially
e
...
Rabbit
Subterranean burrow
Collection of nesting material (Own fur)
Temperature
Shelter against predators

-

Bird Brood Parasitism

- Obligate brood parasitism evolved several times
independently (convergent evolution)

- Facultative parasites
- Cocoo family: not all full-time parasites (59/141
years)

- Success:
- If host observes parasite, low chance
- Host sometimes notice changed number of
eggs

- Host notices strange egg (color, size, pattern)
& removes it

- Rapid development of parasite young
(competitive)

- Intense begging (vocal mimikry)
After Hatching
Imprinting
- Phase-sensitive learning occurring at particular
age or life stage
- Young learn shape, face, voice, odor etc
...
g
...
g
...
temporal gap between support & own
behaviour
- Individuals not related
- e
...
Egg trade in Hamlet-fish, blood gift in
Vampire bats, allogrooming in primates

-

Excuse Reciprocal Behaviour e
...
Vampire Bat

- Problem:
- Often not successful
- Only little resources, survival until next night
unclear

- Strategy:
- Begging
- Result:
- 5/8 individuals got feeding
- No successful animal observed begging
- Donation only for related individuals or member
of same sleeping community

- Individual recognition (social parasitism)
- Need for repetitions (switch of donor & recipient)
- Benefit for donation has to be higher than
investment

- e
...
Kin selection in prairie dogs, meerkats,
gerbils & marmots

- Prerequisite:
- Individual knowledge of members
- Reproductive skew
- Kind of help:
- Alarm calls: benefit own group, other s benefit
accidentally

- Care of young: warming, shelter (burrow)
- Defence of territory
- Foraging

alarm call

- Feeding (energetic benefit for parents)
Alarm Calls
- Anti-predatory - Alert of approaching predators
(benefit for other species)
- Well developed on language level in some nonhuman primates
- e
...
Ring-tailed lemurs, white-faced capuchin
monkeys, Diana monkeys, Campbell’s monkeys,
& vervet monkeys
- Species-specific high frequency sound (often not
perceivable by predators, ultrasound)
- If individual successfully alerts social group yet
doesn’t reveal its location, decrease chance of
caller to be detected & increase chance of social
group to avoid predation
...
g
...

Society - Social appetence, social behaviour
...
Non-anonymous, open vs
...
g
...
g
...
Psychological

Types:

- Stress Response:
- Maintenance of physiological homeostasis
- Autonomic (Fight or Flight)
- Hypothalamic-Pituitary-Adrenocortical (HPA)
systems
Type

Disease & Injury

Pain, nausea &
weakness
Frustration,
boredom & pain

Over exertion

Fatigue, pain &
anxiety

Metabolic demands

Mental

Hunger/Thirst

Confinement

Physiological

Thermal discomfort

Lack of water

Milgram-Experiments (1963)
- Subject gets role of the punisher
- Scientist takes role of pupil (not known by
subject)
- Pupil has to learn lists of words, if he is wrong,
he gets a current pulse,
- For each mistake with increasing volts (>220
volts)
- Different variations of behaviour of scientist,

Associated Feelings

Heat/Cold

Physical
Environments

Stressor

Weakness

Nutritional
deficiencies

Weakness

Behavioural
deprivation

Frustration &
boredom

Social stress

Anxiety & fear

Behavioural Ecology

Revision
Glucocorticoids (Cortisol, corticosterone)

- Mobilises energy stores in short term →
Increases glucose levels in blood

- Stimulates glycogenolysis in liver & suppresses

insulin secretion → Gives negative feedback to
the pituitary gland & hypothalamus, thereby
indirectly to & adrenal glands
...
g
...
g
...
g
...


Hormone Classes

- Proteins & peptides
- Lipids (steroids, eicosanoids)
- Amino acid derived (thyronines,
neurotransmitters)

- Gases (NO, CO)

Peptide vs
...
g
...
g
...
g
...
Release of growth hormone (hypothalamus &
anterior pituitary)
2
...
Inhibition of growth hormone (hypothalamus &
anterior pituitary)

a physiological response that response amplifies
an initial change
e
...
Secretion of oxytocin during birth

- Negative Feedback - A system is activated
-

which sends back reverse information
...
g
...
g
...


- Pheromones of women

Low High Oestrogen/Androgen ratios = Masculine:

Behavioural Ecology

- Growth of jaw, brow ridges, centre of face from
-

brow to bottom of nose, more facial hair, taller,
darker, more muscular, etc
Pheromones of men

Revision

- Parasitoids
- Scavengers
What/When/How to Eat:

- Food: Type, size & quality
- Energetic background:
- Handling time
- Search time (+ predation risk)
- Presence of toxins
Maximising Energy Gains per Unit Time

-

Rate of Energy Gain = Energy Gained / Average Costs = Ei/hi

- Energy gained (E):
- Food quality (size, nutritional content, lack of
toxins, etc
...
g
...
variable food sites
- e
...
Yellow-eyed Juncos switches from being

risk-averse to risk-prone as starvation increased

Interdependencies based on food web
Functional Response
- Change in foraging behaviour of a natural
enemy in response to changes in density of
prey
- Type A - Ever decreasing proportion of prey is
killed as prey density increases

Behavioural Ecology

- Type B - Proportion of prey killed increases at
lower prey densities but decreases at higher
prey densities

Revision

- Proportionally fewer harvested at higher

densities - Satiation reached earlier at higher
densities
...
g
...

- Rx is maintained, but curve is changed
- Steeper curve reduces t
Optimum vs
...

- Distance between patches increases
...

- Maximisation of energy gain
- e
...


Giving Up Density

- Brown (1988): Density of nutrition on which

-

animal will give up foraging at a particular
patch
...
g
...
g
...
g
...
g
...
g
...

- More rapid habituation to predator
...
pulmonary stress)
- Metabolic costs (nutritional requirements)
- Locomotor performance costs
- Time to store up reserves:
- Passerine birds store more body fat at lower
temperatures
- Grey tits put on weight when artificially
shorten photoperiod
- Feeding in evening, before nightfall based on
predicted night time temperatures
...
g hourly, daily or yearly
Purpose:
- Promotes ability to survive by coordinating
activities with changes in environment
- Coordinates internal processes
e
...
Heart rate
...
REM ratio depends on cognitive
activity

Environmental Cues
- Day-long rhythms (24h):
- Light & darkness
- Temperature
- Humidity
- Lunar cycle (29
...
g
...

Intrinsically photosensitive retinal ganglion cells:
Rare, 1
...
g
...
5-7
...
5 Hz (synchronized)
Sleep spindles: short bursts of 12-14 Hz activity
K complexes: very brief large spike activity
Lower frequencies are usually higher amplitude
(synchronized) activity

-

Sleep Stage Cycles

- 4 stages:
- REM-Sleep:
- Brain highly active
- Muscle paralysis
- Non-REM-Sleep:
- Low brain activity
- Average muscle activity

Behavioural Ecology
Special Forms of Sleep
e
...
Dolphins & Co
...
g
...

- Most behaviours incorporate elements of both
e
...
Hunting in orca packs & tool use

Clever Hans (1890s)

- Horse in possession of retired school teacher,
Mr
...


- Could answer complex questions by stomping
foot correct number of times
...

Student, Oskar Pfungst, investigated further:
- Horse could not answer correctly unless
questioner knew answer
...

e
...
by your eye movements, breathing rhythm non-verbal communication widely distributed

Habituation

- Animal trained to ignore stimuli
Classical or Pavlovian Conditioning
Pavlov’s dog
Animal learns to respond to particular stimuli
Basic obedience training
Unconditioned Stimulus (US):
- Automatically elicits a response (reflex)
- Unconditioned Response (UR):
- Food, Water, Sex, Pain,
- Initially “neutral” – Does not initially trigger
same response as US
- Lights, sounds, tastes, odours,
- After pairings with US, elicits a conditioned
response

-

A typical torpor bout:
Animal drops Tb to near Ta slows metabolism (2-6
hours)
↓
Respiration, heart, metabolic rates drop
↓
Animal remains at low tissue temp (6-8 days)
↓
Metabolic process occur at very low levels
↓
Animal returns to euthermic temperature (1-2 hours)
↓
Metabolic & cardiovascular rates speed up
↓
Animal becomes active

COGNITION & LEARNING

Instrumental Conditioning

- Trial-&-error learning
- Skinner Box, labyrinth
- Behaviour can be “shaped”
Latent of Associative Learning

- Exploratory learning
- No obvious reward
- Helps animal learn about its surroundings
Perception of Fear

- Brain area amygdala (all emotions)
- Experimental evidence: Inactivation of amygdala
during training prevents fear conditioning

- Inactivation of amygdala immediately after
conditioning blocks memory formation
What is the explanation for the reactions:

Behavioural Ecology

Revision

Current state for formation of memories

- Do we form memories because we need to

remember something or to retain experiences
...
g
...


- Knowledge of other: Plovers moved further away
The Case of H
...

- Removed:
- Amygdale
- Perirhinal cortex,
- Entorhinal cortex
- 2/3 of Hippocampus

for “dangerous” intruders than “nonthreatening”
intruders
Should Monitor Intruder: Starts display when
intruder can see it, if intruder stops following,
plover intensifies display & approaches intruder
...
g
...
g
...


Behavioural Ecology
Experimental Design
Learning is more difficult to observe than learned
behaviours
...
g
...
g
...
g
...
g
...

Landmarks: Cognitive Maps

- e
...
Bird migration follows routes over land
- e
...
Insects pinpoint locations they need to find
again by learning arrangement of surrounding
landmarks

system of macroscopic geometric relations
among surfaces in environment used to plan
movements through environment
...
home-range)
- Geometric content (metric, topological)
- Reference frame (egocentric vs
...
g
...
g
...
g
...
g
...
Group spacing & coordination
2
...
Reproduction (identifying/attracting mates)
4
...
Alarm (warning)
6
...
Soliciting play
8
...
Synchronization of hatching

Behavioural Ecology
Signal - Physical form in which a message is coded
Discrete vs
...
g
...
g
...
g
...
Mechanoreception
- Tactile information (proprioception)
- Acoustic signals (auditory reception)
2
...
Vision
4
...
Electroreception
6
...
g
...
g
...
g
...
g
...
g
...
(also pick up chemical cues)
- Vertebrate copulation ➞ Tactile stimulation
elicits lordosis response in female mammals
- Touch (e
...
vaginal stimulation) can induce
ovulation in some species
Tactile Signals
Range? - Short
Travels around objects? - No
Useful at night? - Yes
Fade-out time? - Fast
Cost to sender? - Low
Sender can be located
Only simple messages

Properties of Sensory Channels
- Range – Short-Long
- Transmission Rate – Slow-Fast
- Can it travel around objects? – yes or no
- Can it be used at night? (yes, no, or sometimes)
- Fade-out time (how long does it last? - Slowfast)
- Locate sender? (Easy-difficult)
- Cost to send signal (Low-high)
- Complexity of message (Low-high)

-

Acoustic Signals
- Can occur within or outside of human
“umwelt” (~20-20,000 Hz)
- Ultrasonic (high frequency e
...
, echolocation)
- Infrasonic (low frequency e
...
, African elephant
rumbles, whale song)

- Markings, patterns, colour require vision
- Mostly used by diurnal species (visual displays),

Acoustic Signals
- Range? - Depends on wavelength
- ravels around objects? - Yes
- Useful at night? - Yes
- Fade-out time? - Fast

Visual Communication

e
...
, aggressive displays of SFF

- Consider bioluminescence
- Exception: fireflies
- Species-specific flashing to attract mates &
during courtship

- “femme fatales” of Photuris versicolor (deceit)
Visual Signals

- Range? - Medium

Behavioural Ecology

-

Travels around objects? - No
Useful at night? - Depends
Fade-out time? - Fast
Cost to sender? - Medium
Sender can be located
Complex messages possible

Electric Signals
- Some sharks & electric fish detect prey’s electric
field using electroreceptors
- Strongly electric fish (e
...
electric eel) have
EODs (electric organ discharges of 100V)
- Social communication possible by altering
wavelength/ pulse duration
Electric Signals
Range? - Short
Travels around objects? - Yes
Useful at night or in murky waters? - Yes
Fade-out time? - Fast
Cost to sender? - Depends
Sender can be located - More simple messages


Receptors - Three primary roles of sensors:
- Exteroreceptors - Detect external signals such
as light, chemicals
- Interoreceptors - Detect internal body signals
such as blood pressure
- Proprioceptors - Detect the animal’s position in
space

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Revision
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Sensory Pathways
- Sensory pathways convey type & location of
sensory stimulus
- Type of receptor activated
- Brain has a map of location of each receptor

- Signaler - Individual creating a signal to illicit a

Receptors
- Perception: Interpretation of external world as
created by brain from nerve impulses delivered
by sensory receptors
- Problem:
1
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- Threshold shifts to right (less stringent) to

reduce rejection errors if they are too costly
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