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??:????? (Communication: Channels and Functions) -- ????? (Ethology)

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Title: ??:????? (Communication: Channels and Functions) -- ????? (Ethology)


1
??????? (Communication Channels and Functions)
-- ????? (Ethology)
??? ??????????? (??)
2010 ? ??
  • ???(Ayo)
  • ?? ???? ???????
  • ????????? ??

Ayo NUTN Web http//myweb.nutn.edu.tw/hycheng/
2
Part 3. ??????
  • ???? (Reproductive Behavior)
  • ????????? (Parental Care and Mating Systems)
  • ??????? (Communication Channels and Functions)
  • ????? (The Evolution of Communication)
  • ?? (Conflict)
  • ????,????? (Group Living, Altruism, and
    Cooperation)

3
15a ???????
Communication Channels and Functions
  • The definition of Communication channels
  • Vision
  • Audition
  • Substrate vibration
  • Chemical senses
  • Touch
  • Electrical fields
  • Multimodal communication function
  • Species recognition
  • Mate attraction
  • Courtship and mating
  • Maintaining social bonds
  • Alarm
  • Aggregation
  • Agonistic encounters
  • Communication about resources a case study

By Goodenough, McGuire, and Jakob
4
Important messages are sometimes whispered
  • When male Asian corn borer moths are close to a
    female, they
  • Rub specialized scales on their forewings against
    their thorax
  • Produce extremely low intensity ultrasonic
    courtship songs
  • Courtship songs suppress escape behavior of the
    female and facilitate mating
  • The quiet song lowers the risks of eavesdropping
    (?????) by rival males and predators

5
Defining communication
  • Communication occurs when a sender produces a
    signal that contains information
  • And is detected by a receiver who interprets the
    signal and decides how to respond
  • But sometimes an animal is not intended to
    receive a message
  • i.e. an owl hears the noises from a mouse
  • Cue provides information to another animal but
    does not benefit the sender

6
Animals must benefit from a signal
  • The sender benefits from the transmission by
    altering the behavior of the receiver
  • Signal a courtship dance, song, feather crest
  • Display a stereotyped sequence of behaviors that
    has a signaling function
  • On average, receivers must benefit from paying
    attention to a particular signal
  • But receivers do not always benefit
  • Sometimes senders manipulate receivers by sending
    dishonest signals

7
Channels for communication
Feature Visual Auditory Chemical Tactile Electrical
Effective distance Med Long Long Short Short
Localization of sender High Med Var High High
Go around obstacles Poor Good Good Poor Good
Speed of transmission Fast Fast Slow Fast Fast
Complexity High High Low Med Low
Duration Var Low High Low Low
8
Properties of visual signals
  • Ease of localization the location of the sender
    is known
  • The receiver can see and, therefore, respond
  • Rapid transmission and fade-out time
  • As soon as the sender stops displaying the signal
    is gone
  • Visual systems provide a rich variety of signals
  • Brightness, color, spatial and temporal patterns,
    movement and posturing
  • But, if the sender cannot be seen, its signals
    are useless
  • Vision is easily blocked
  • They are hard to see during nighttime or in dark
    places
  • The size of visual signals decreases with distance

9
Environmental conditions affect visual stimuli
  • During agonistic displays, shark species strongly
    depress both pectoral fins and hold them down
  • Sharks in clear water have conspicuous markings
    on their pectoral fins
  • Black or white tips and margins enhance the
    visibility of this postural display
  • Sharks living in habitats where light is scarce
    only use the posture

10
  • In many sharks, agonistic displays involve
    symmetrical depression of the pectoral fins (??).
  • (a) a Galapagos shark using this visual signal of
    agitation.
  • (b) Blacktip reef shark have markings on their
    pectoral fins that may enhance the agonistic
    display.

11
Use of visual signals in territorial communication
  • If a roving razorback sucker fish approaches a
    territorial male
  • The territorial male rolls his eyes, exposing the
    whites of his eyes
  • The interloper (???) retreats

12
Species use visual signals
  • At night or in dark places
  • Nocturnal species that cannot produce light use
    visual signals
  • Are most active at dawn and dusk, when light is
    available
  • Colors are difficult to distinguish so visual
    signals focus on contrast and involve white
  • Eagle owls have white feathers on their throat
  • Visible when the throat is inflated and deflated
    during vocal displays

13
  • Although eagle owls are nocturnal, they use
    visual signals at dawn and dusk when some light
    is available.

14
The size of visual signals
  • Conspicuousness of visual signals diminishes with
    distance
  • Animals adjust their visual signals with respect
    to receiver distance
  • Courting male fiddler crabs broadcast their
    courtship displays if a receiver (female
    conspecific) is absent

15
As distance decreases, the interval and duration
between claw waves decreases
  • (a) stages in the claw-waving display of male uca
    perplexa.
  • (b) the interval between claw waves,
  • (c) the duration of claw waves

16
  • (d) the horizontal sweep of the claw tip decrease
    with decreasing receiver distance.
  • Thus, as distance to receiver decreases, male
    displays increase in intensity but become less
    conspicuous.

17
Properties of auditory signals
  • They can be transmitted over long distances
  • Especially in water
  • A rapid means of sending a message
  • Particularly at close range
  • Conveys a message when there is limited
    visibility
  • Night, deep water, dense vegetation
  • Sound signals can be complex
  • Temporal variation of frequency (pitch) and
    amplitude (loudness)

18
Animals produce a variety of sounds
  • Sounds are generated by structures that have
    evolved in association with respiratory
    structures
  • Mammals have a larynx
  • Birds have a syrinx that produces complex sounds
  • Sounds are generated by striking objects
  • Rabbits and deer signal by foot stamping
  • Beavers slap(??) the water
  • Woodpeckers drum on trees
  • Sounds are generated by rubbing appendages
    together
  • Insects rub parts of their exoskeleton together

19
Sound production stridulation (????)
  • Stridulation sound production by rubbing body
    parts together
  • Cricket wings have a thickened edge scraper that
    rubs against a row of ridges (the file)
  • Is not confined to insects
  • A male club-winged manakin creates sound by
    moving his wings and highly modified secondary
    feathers

20
  • A male club-winged manakin creates sound by
    moving his wings and highly modified secondary
    feathers

21
Some animals make sounds that humans cannot hear
  • Ultrasounds sound frequencies are above those
    audible to humans
  • Cetaceans, bats, rodents and other animals
    produce and detect ultrasounds as part of
    echolocation
  • Male and female concave-eared torrent frog calls
    have audible and ultrasonic components
  • Males approach calling females (positive
    phonotaxis)
  • Species can avoid the masking effects of the
    low-frequency background noise of streams and
    waterfalls

22
  • concave-eared torrent frog ???(??Amolops
    tormotus)???????????,???????????????????????????,?
    ??????????????????380?700????????????????

23
Infrasound
  • Humans cannot hear frequencies below 20 Hz
    (infrasound)
  • Most elephant calls are infrasonic
  • Infrasonic calls have the same source as audible
    calls
  • Air driven from the lungs moves the larynx
  • Elephants are social animals that live in
    matrilineal family groups
  • Daughters remain with mothers
  • Sons live in bachelor groups
  • Long distance communication between family
    members and groups is critical

24
Infrasound works well for long distance
communication
  • Low frequency sounds are less degraded
  • Through refraction (bending of sound waves as
    they pass from one medium to another of different
    density)
  • Reflection (the bouncing off of a new medium)
  • Absorption (the conversion of sound energy to
    heat)

25
Substrate vibration
  • Animals can communicate by seismic signals
    encoded in the pattern of vibrations of the
    environment
  • The ground or water surface
  • Produced through percussion on the substrate
  • Kangaroo rats (????) declare territory ownership
    through foot drumming
  • Blind mole rats bang their heads against the
    burrow ceiling
  • Water striders use vibrational signals for sex
    identification, mate attraction, courtship, and
    territorial defense

26
  • Kangaroo rats (????)
  • Blind mole rats
  • Water striders

27
Elephants monitor airborne and ground signals
  • Elephants distinguish subtle differences between
    seismic calls
  • To discriminate between alarm calls of familiar
    and unfamiliar conspecifics
  • Elephants detect seismic signals through two
    pathways
  • Bone conduction through the feet, front legs to
    the shoulders, and to the middle ear
  • Mechanoreceptors in the skin of the trunk and
    feet
  • Elephants monitor ground-borne and air-borne
    signals to determine the distance of the
    vocalizing individual

28
Properties of chemical signals
  • Smell and taste are another channel for
    communication
  • Based on the movement of odor molecules from
    signaler to receiver
  • Information may be carried by chemicals over long
    distances
  • By currents of air or water
  • Rates of transmission and fade-out time are
    slower than for visual or auditory signals

29
Chemical signals are durable (???)
  • They remain after the signaler has gone
  • Delineation (??) of territorial boundaries
  • Some mammals increase the signal life of
    chemicals
  • Secreting them with oily carrier substances or
    urinary proteins
  • Do not require continued energy expenditure by
    the sender
  • Used where visibility is limited
  • It is more difficult to locate a signaler using
    chemicals than visual or auditory signals

30
Signals are complex blends of chemicals
  • The proportions of different chemicals produce
    their effects
  • Effects are produced by the full chemical image
    of the signal (the odor mosaic)
  • Scent marking the act of strategically placing a
    chemical mark in the environment
  • Female marmosets (??) discriminate familiar from
    unfamiliar conspecifics
  • Each female has a unique scent signature (odor
    mosaic) based on the ratios of chemicals in the
    scent mark

31
  • marmosets (??)
  • Common marmosets deposit scent marks that are
    complex combination of many chemicals.

32
A signals meaning varies
  • With the context in which it is given
  • As worker bees groom a queen honeybee they pick
    up a chemical signal
  • And distribute it throughout the hive
  • The chemical prevents the rearing of any
    additional queens
  • The queen also exudes this chemical on her
    nuptial flight
  • Causing males to gather around her
  • This same chemical serves as a queen inhibitor or
    as a sex attractant
  • Depending on the context

33
Detection of chemical cues may occur at a distance
  • Remote chemoreception airborne chemical cues
  • Contact chemoreception chemical cues are
    detected through direct contact with the chemical
    signal
  • One ant touches another ants body to evaluate
    chemicals on the other ants body
  • To determine if the individual is a colony member
    or an intruder
  • Contact chemoreception is associated with
    nonvolatile chemical cues

34
Some animals have organs for chemical
communication
  • Amphibians, reptiles, and mammals may have a
    vomeronasal (Jacobsons) organ
  • For communication between mates, parents and
    offspring, and rivals
  • Its neural wiring does not go to the main
    olfactory system
  • It is located in the roof of the mouth or between
    the nasal cavity and the mouth
  • Communicative chemicals reach it through the
    nose, mouth, or both

35
The flehmen response
  • Chemicals are nonvolatile and must be brought to
    the organ
  • In a snake, the chemicals are delivered by the
    tongue
  • A mammal licks or touches its nose to the
    chemicals and make a facial grimace(??) (flehmen)
  • To transfer the chemicals to the organ
  • The flehmen response (from German flehmen,
    meaning to curl the upper lip), is a particular
    type of curling of the upper lip in ungulates,
    felids, and many other mammals, which facilitates
    the transfer of pheromones and other scents into
    the vomeronasal organ, also called the Jacobson's
    Organ.

36
  • Flehmen is a characteristic posture in which the
    head is raised and upper lip is curled back. It
    serves to deliver nonvolatile communicatory
    chemicals, such as those found in urine or
    glandular secretions, to the vomeronasal organ.

37
Pheromones (???)
  • Chemicals produced to convey information to other
    members of the same species
  • Releaser pheromones have an immediate effect on
    the recipients behavior
  • A female silk moth emits a minuscule amount of
    her powerful sex attractant bombykol
  • Males immediately turn and fly upwind to find her

38
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39
Releaser pheromones
  • Trail pheromones in insects direct the foraging
    efforts of others
  • Alarm substances in insects warn others of danger
  • Lactating rabbits produce mammary pheromone
  • Which stimulates their pups to search for and
    grasp onto a nipple

40
Primer pheromones
  • Exert their effect more slowly
  • By altering the physiology and behavior of the
    recipient
  • A queen honeybee produces pheromones that keep
    her as the only reproductive individual in the
    colony
  • Prevents workers from feeding larvae the special
    diet that would cause them to develop into rival
    queens
  • When the queen dies the inhibiting substance is
    no longer produced and new queens can be reared

41
Vertebrates produce primer pheromones
  • So reproduction occurs in the proper social or
    physical setting

Origin Recipient Effect
Female urine Female Inhibits cycling and ovulation
Male urine Female Induces cycling and ovulation
Female urine Male Prompts release of testosterone and luteinizing hormone
42
The vomeronasal organ
  • There are no functional differences between the
    vomeronasal organ
  • And the main olfactory system
  • The organ can be stimulated by substances other
    than pheromones
  • A hunting snake responds to chemical cues of prey
    brought to the organ by the flicking tongue
  • Chemicals from prey species are not pheromones
    (communication within a species)
  • The behavior is foraging - not communication

43
Pheromones can act via the olfactory system
  • Scent marks left by a female hamster prompt a
    male to locate her
  • In a sexually inexperienced male, another
    component of the vaginal secretion perceived
    through his vomeronasal organ prompts him to
    investigate and mount her
  • Sexually experienced males have learned the odor
    cues of receptive females
  • And no longer need the vomeronasal organ to
    stimulate mounting

44
Properties of tactile signals
  • Animals communicate by touch
  • Tactile messages can be sent quickly
  • It is easy to locate the sender, even in the dark
  • It is effective over short distances but not
    around barriers
  • Honeybee scouts inform nest mates of the location
    of a food source by dancing
  • Recruits follow the dancers movements by
    touching them

45
  • Social grooming, a form of tactile communication
    that builds and maintains social bonds, is
    displayed by many mammals, including horses.

46
A message sent by touch can be varied
  • By how the recipient is touched,rubbing (??),
    patting(??), pinching (??)
  • Where the recipient is touched
  • The frequency and duration of touching
  • The extent of surface area touched
  • Humans send and decode tactile signals

47
Electrical fields
  • Two distantly related groups of tropical
    freshwater fishes produce weak electrical signals
    used in orientation and communication
  • Knifefishes of South America
  • Elephant-nose fishes of Africa
  • Torpedo rays and electric eels generate very
    strong electric discharges to stun prey or
    predators

48
Electrical signals
  • Are generated by electric organs derived from
    muscle
  • Muscle cells are arranged in stacks
  • Their currents are added to result in a stronger
    current
  • When an electric organ in weakly electric fish
    discharges
  • An electrical field is created around the fish
  • This field is the basis of the signal

49
Creating diverse electrical signals
  • Different signals can be created by varying
  • The shape of the electrical field
  • The discharge frequency
  • The timing patterns between signals
  • Stopping the electrical discharge
  • Electroreceptors in the skin detect electric
    organ discharges

50
Patterns of electric discharge in weakly electric
fish
  • Wave-type pattern
  • Produces signals continuously
  • Waveform resembles a sine wave
  • Pulse-type patterns produce electricity at higher
    rates when active
  • And at lower rates when resting
  • The waveform has a complex multiphasic structure

51
  • (b) Wave type Some species of weakly electric
    fish produce electrical signals continuously with
    monophasic waveforms.
  • (c) Pulse type Other species produce electrical
    signals in a pulse pattern, often with
    multiphasic waveforms. These so-called
    pulse-fish discharge at high rates when active
    and low rates when at rest.

52
  • Sternopygus macrurus
  • Eigenmannia virescens
  • Apteronotus albifrons (????)
  • Sternarchorhamphus macrostomus (????)

53
  • Rhamphichthys rostratus
  • Gymnorhamphichthys hypostomus
  • Hypopygus lepturus (????)

54
Properties of electrical signals
  • When an electric organ discharges
  • An electrical field is created instantaneously
  • It disappears the instant the discharge stops
  • They transmit information that fluctuates quickly
  • i.e. aggressive tendencies
  • It does not propagate away from the sender
  • But exists as an electrical field around the
    sender
  • Its waveform is not distorted during transmission
  • So it is a reliable indicator of the senders
    identity
  • Waveforms are different between the sexes
  • And among different species

55
Electrical signals suit the environment
  • For communication in animals
  • Active at night
  • That live in muddy tropical rivers and streams
  • That live at depths where visibility is poor
  • They can move around obstacles
  • And are undisturbed by suspended matter
  • However, they are effective only over short
    distances
  • Different weakly electric species may coexist in
    an area
  • So the short effective distance of the signal
    reduces electrical noise when many individuals
    signal at once

56
Electric signals send the same messages
  • That other animals send through other channels
  • Males of some species advertise their sex and
    species by electrical signals
  • They also court females by singing an
    electrical courtship song
  • Signals are also used during agonistic encounters
  • Patterns of discharge are associated with
    aggression, dominance, and submission
  • Parents and offspring may communicate via
    electrical signals, to remain close to each other

57
Multimodal communication
  • Multimodal communication animal displays
    contain signals from two or more sensory
    modalities
  • Signaling occurs simultaneously or sequentially
  • The courtship display of a male bird may
    simultaneously contain visual and auditory
    signals
  • Elephant vocalizations have seismic (ground
    borne) and auditory (airborne) components
  • Messages conveyed in different signaling channels
    can be
  • Redundant convey the same thing or
  • Nonredundant convey different things

58
Multimodal messages in spider courtship
  • The courtship display of male brush-legged wolf
    spiders contains visual and seismic signals
  • Visual component the male raises and lowers his
    first pair of legs
  • Seismic(??) components stridulation (????) , up
    and down bouncing of the body, and striking the
    substrate with mouthparts

59
  • Male brush-legged wolf spider

60
Benefits and costs of multimodal communication
  • Benefits for nonredundant multimodal signals
  • More information can be sent per unit time
  • Insurance that the message is received and
    recognized
  • Costs for signaling in multiple sensory
    modalities
  • Requires more of the senders energy
  • Recipients need more energy to receive and
    process multiple signals
  • May make senders and receivers more susceptible
    to predation

61
Functions of communication species recognition
  • Conspecifics are competitors for food, shelter
    and mates
  • But potential mates or members of a social group
    should be wooed (??)
  • Its adaptive not to mistake heterospecifics for
    conspecifics
  • Dont waste time and energy courting an animal
    with whom it is impossible to produce viable
    offspring
  • Dont defend a territory from an individual that
    is not competing for resources or mates

62
All sensory channels are used for species
recognition
  • Birds use song frequency (which notes are sung)
    and syntax (??) (how the notes are strung
    together)
  • Crickets rely on differences in song temporal
    patterns
  • Insects use olfactory cues
  • Some species use species-specific pheromones to
    attract mates
  • Others rely on visual cues, such as displays or
    color patterns

63
Selection for different species signals
  • Male frogs and toads attract their mates by
    calling at night
  • A female must choose one of her own kind from the
    variety of callers at the local pond
  • Who is the strongest?

64
Animals can fail to distinguish conspecifics
  • Males of many species indiscriminately court
    females
  • Australian beetles attempt to copulate with
    discarded beer bottles
  • Even females, the more selective sex, sometimes
    make erroneous choices (?????)
  • In recently introduced invasive species that
    share some traits with natives
  • Natural selection has not had time to favor those
    individuals that can successfully make the
    distinctions

65
Signals that attract a mate
  • Must be species-specific
  • Easy to locate
  • Effective over long distances
  • Chemical and auditory signals are used
  • Female silkmoth pheromones attract males from 100
    meters away
  • Auditory signals carry well
  • Amplified by communal displaying or anatomical or
    environmental structures
  • Courtship songs attract mates from long distances

66
Female crickets gather on a loudspeaker that
broadcasts the males courtship song
67
Stop and think
  • When males signal to attract prospective mates,
    they give auditory or visual signals
  • Females that signal usually use the olfactory
    channel
  • Why might this be so?
  • Think of the duration of receptivity, the costs
    of signals, and the dangers of signaling

68
Communication identifies the opposite sex
  • Individuals court before committing themselves to
    mating
  • Animals communicate their sex
  • Differences between males and females are
    apparent
  • i.e. antlers and other secondary sexual
    characteristic
  • Species showcase aspects of their body that
    indicate their sex
  • A female stickleback reduces the probability of
    attack by assuming a head-up position
  • That displays her egg-swollen abdomen

69
Identification of the opposite sex
  • Some gender differences are subtle
  • Male blue-ring octopuses cannot distinguish males
    from females Until late in the courtship sequence
  • Octopuses mate by inserting their modified third
    right arm in to the mantle cavity of the female
  • And releasing a spermatophore (sperm packet)
  • Male blue-ring octopuses insert their arm
    indiscriminately into both males and females
  • But only release spermatophores in females
  • Male-male interactions are brief and not
    aggressive
  • Fitness costs of making an insertion into a male
    are low

70
  • blue-ring octopuses

71
Communication mate assessment
  • Courtship allows a female to judge the qualities
    of her suitor
  • So she can choose the one most likely to enhance
    her own reproductive success
  • More rarely, it allows the male to choose the
    characteristics of an appropriate female
  • Courtship displays provide a means for evaluating
    the suitors qualities
  • His physical prowess (????)
  • Ability to provide food for the offspring
  • The extent of his commitment

72
Female birds assess male quality
  • Male common terns (??) catch fish and offer them
    to the female
  • She compares the quantity of fish provided by her
    suitors
  • And chooses the best fisherman
  • Male wheatears, a small bird, collect stones in
    their beaks
  • And carry them to cavities that serve as
    potential nest sites
  • Females watch the males carry stones and even
    assess their weight
  • Male wheatears that carried heavier stones scored
    better on a test of immunocompetence (an
    indicator of male health)

73
  • common terns ??
  • wheatears

74
Communication coordinationof behavior and
physiology
  • Male and female reproductive systems are not
    always synchronized
  • Courtship displays can function to coordinate the
    couples behavior and physiology
  • ??ring doves

75
  • The mating behavior of a pair of ring doves.
  • The sight of the female causes the male to
    increase his testosterone production, and he
    begins to display.
  • In response, the female coos (???) , and her own
    vocalization stimulates estrogen production.

76
Many courtship displays are visual or tactile
  • Displays coordinating receptivity occur at close
    range
  • Some displays rely on pheromones delivered at
    close range
  • A male mountain dusky salamanders courtship
    pheromone makes the female more receptive
  • The female indicates her receptivity and the male
    deposits a spermatophore

77
  • During courtship, a male dusky salamander injects
    a female with his courtship pheromone.
  • (a) the male alternately scrapes the females
    back with his teeth and swabs her with the
    pheromone, which is produced by a gland beneath
    his chin. The female signals her readiness to
    mate by placing her chin on the base of the
    males tail and straddling his tail.

78
  • (b) the courtship pheromone makes the female
    receptive. Tail straddling and mating occur
    quickly when a female has been treated with a
    courtship pheromone compared to a control
    treatment with saline.

79
Communication maintenance of pair bonds
  • Formation of bonds between (relatively)
    monogamous pairs of animals
  • Pair-bond displays occur at close range
  • Are visual or tactile
  • Dusky titi monkeys sit with their tails
    intertwined

80
Pipefish maintain pair bonds year-round
  • Pipefish are long skinny fish related to
    seahorses
  • Pairs are monogamous
  • Male and female pipefish conduct a greeting
    ceremony every morning
  • Greetings are even carried out during the
    nonreproductive season
  • Functions solely to maintain the bond with the
    partner for the next breeding season

81
Maintaining social bonds
  • Social group members use communication to
    maintain bonds
  • Based on contact resting together, nuzzling,
    touching
  • Greeting signals assure nonaggression
  • Chimpanzees greet each other by touching hands
  • Sea lions rub noses
  • Lions rub cheeks
  • Cats head-bump
  • Social grooming is different from self-grooming
  • Skin care is not the most important factor in
    social grooming

82
Maintaining social bonds in primates
  • In primates, grooming smooths over tension and
    restores relationships after conflicts

83
Alarm
  • Alarm signals warn another animal of danger
  • Predators
  • Guard against other members of their species bent
    on infanticide or other form of aggression
  • Alarm signals can cause animals to flee or
    assemble
  • Flee signals are easy to make quickly but
    difficult to locate
  • Rapid visual signals flash of a deers tail
  • Volatile pheromones that diffuse quickly
  • High-pitched sounds

84
Alarms cause animals to flee or take cover
  • Species share similar alarm signals
  • Some species even respond to the signals of other
    species
  • Eurasian red squirrels flee or increase their
    vigilance when they hear the alarm calls of
    Eurasian jays

85
Vervet monkeys use specific alarm calls
  • When a snake is seen, they emit a low-amplitude
    alarm call
  • Capturing the attention of individuals near the
    caller
  • Other monkeys respond by looking at the ground
  • With a leopard, monkeys make loud, low-pitched,
    abrupt chirps
  • The call is audible from a great distance
  • The caller is easy to locate by its fellows
  • Monkeys scatter and run for cover
  • With an eagle, monkeys emit loud, low-pitched
    staccato grunts
  • Easily located and transmitted over long
    distances
  • Other monkeys run into thickets

86
Alarm calls that cause animals to assemble
  • Alarm signals cause those who hear them to
    congregate
  • To defend a resource
  • Or drive off predators
  • Assembly signals need to easily locate the
    signaler
  • Be longer-lasting
  • And repetitive
  • Responses can be complex
  • Ants respond to alarm pheromones by stopping.
    then raising their heads, moving toward the
    source of the pheromone, and biting the enemy

87
Aggregation
  • Animals aggregate for other reasons besides alarm
    calls
  • To hibernate, share a resting place or a roost,
    prepare for migration
  • Bedbugs come out from hiding places and bite
    sleeping humans
  • They release an aggregation pheromone to find
    each other
  • Aggregating bugs have decreased sensitivity to
    desiccation
  • Protection from predators
  • Ease of finding mates

88
Agnostic encounters
  • Animals conflict with conspecifics over
  • Food
  • Territory
  • Mates
  • Their places in the dominance hierarchy
  • Are actions involved in conflict
  • Aggressive behaviors
  • Threats and attacks
  • Submissive behaviors, appeasement or avoidance
  • Bighorn sheep butting heads, cats hissing, and
    dogs rolling on their backs

89
The honeybee communication system
  • Honeybees are central-place foragers
  • Leaving from a shared nest to collect food
  • All the labor is done by female worker bees
  • Older bees forage for flowers, nectar and pollen
  • Flowers can be widely scattered
  • Foragers communicate about the new food source to
    other bees
  • Returning foragers do a characteristic dance
  • Other bees follow dancers
  • Karl von Frisch studied the dance language for 50
    years

90
The two dances of honeybees
  • Round dance the bee runs in a circle, reverses
    direction and circles again
  • Waggle dance the shape of a figure 8
  • During the central run, the bee waggles her
    abdomen and buzzes her wings
  • These dances indicate food sources and distance
    information
  • The round dance does not convey direction
    information
  • Tells recruits to search for nearby food
  • The waggle dance provides distance information

91
  • (a) the round dance, performed after finding food
    near the hive.
  • (b) the waggle dance, performed after finding
    food greater than about 50m from the hive.
    During the waggle run through the center of the
    figure 8, the bee waggles her abdomen and buzzes
    her wings.

92
The waggle dance provides distance information
  • After the waggle dance, bees appeared at the
    scent plate nearest to the original feeding
    station
  • This dance says food is far away
  • And also encodes information about direction and
    distance by different aspects of the waggle dance

93
  • The setup of a fan experiment to determine
    whether bees use directional information.
  • The solid square shows the position of the
    feeding station during training, and squares show
    the position of the scent plates, which had no
    food.
  • After following a waggle dance, most recruits
    arrive at the scent plate nearest the site of the
    feeding station. The number of bees arriving at
    each station is indicated.

94
  • The setup of an experiment to determine whether
    bees use distance information.
  • The solid square shows the position of the
    feeding station during training, and circles show
    the position of the scent plates.
  • After following a waggle dance, most recruits
    arrive at the scent plate nearest the site of the
    feeding station.
  • The number of bees arriving at each station is
    indicated.

95
Dances provide information about direction
  • The waggle dance helps a bee determine its
    departure direction
  • To know which way to go, bees need to know the
    angle formed by
  • The suns azimuth (the point on the horizon below
    it), the hive, and the flower
  • Dancing bees convey this angle

96
Bees use the angle of the run with respect to
gravity
  • The angle between the waggle run and up on the
    comb is the same as the angle formed between
  • The flower, the hive, and the azimuth
  • If a bee needs to fly toward the sun to reach the
    flower
  • The waggle run is oriented straight up
  • If the bee must fly directly away from the sun
  • The waggle run is oriented straight down
  • If the food source is 20 to the right of the sun
  • The bee does a waggle run 20 to the right of
    vertical

97
Bees adjust the angle of their dances
  • To account for the earths rotation as the sun
    appears to move across the sky
  • Dancing bees adjust the angle of their dances by
    15 an hour
  • These directions are not precise
  • Dancing bees repeat their dances
  • Observing bees take an average of the runs to
    select a direction in which to fly
  • Directions in the dance get bees to the general
    area of the resource
  • From there they use scent to pinpoint the
    flowers location

98
Dances encode information about distance
  • Distance to the food source is correlated with
    two features of the waggle run
  • More waggles the greater the distance to the
    food
  • Longer sound trains of buzzes greater distance
    to food
  • The two dances are not as discrete as they first
    appeared to be
  • Round dances contain brief waggle phases that
    contain distance information
  • Round dances contain directional information but
    are less precise than waggle dances.

99
New technology offers additional insights
  • Tiny harmonic transponders attached to bees
  • Return signals to a radar
  • Researchers can accurately map the paths of
    individual bees
  • Bees that had followed a dance went straight to
    the feeder
  • They did not use odor cues to find the feeder

100
Displaced bees
  • If bees leaving the hive were captured and
    displaced
  • They did not fly in the true direction of the
    feeder
  • But searched where the dancer had led them to
    expect the feeder to be relative to their release
    point

101
Researchers can talk to bees
  • By using a mechanical model of a dancing bee
  • The models dance was not as effective as a live
    bees dance
  • Most recruits still showed up at the feeding
    station indicated by the dance
  • Wagging movements and buzzing are two critical
    components of the dance

102
Bees use optic flow to learn about distance
  • Bees rely on visual cues to estimate how far they
    have traveled
  • And convey that information to other bees
  • Bees trained to fly into tunnels painted with
    vertical stripes overestimated the distance they
    flew
  • The round dance is given when resources are
    within 50 m of the hive
  • The waggle dances are for longer distances
  • All the tunnels were well within the 50 m mark

103
Bees can be tricked
  • When bees flew through a tunnel with vertical
    stripes
  • They acted as if they had flown a long way
  • And performed a waggle dance
  • Even when the tunnel was only 6 m from the hive

104
Other cues are also used in foraging
  • The waggle dance directs bees to a particular
    area
  • But not that precisely
  • The location of the flower is pinpointed by odor
    cues
  • Dance followers detect food scents on the dancers
  • Besides chemical they pick up from food
  • Dancing foragers also produce other chemicals
    from their abdomens
  • These chemicals cause bees to become primed to
    look for food

105
Summary
  • Communication occurs when information is
    transferred from the sender to the receiver and
    the sender benefits, on average
  • Signal a behavior that transmits information
  • Communication channels visual, auditory,
    chemical, tactile or electrical, each with their
    own
  • Effective distance, localization of sender,
    ability to go around obstacles, speed of
    transmission, complexity, duration
  • Pheromones chemicals that convey information to
    conspecifics
  • Vomeronasal organs sense chemical cues
  • Multimodal communication animals communicate
    using signals from more than one sensory channel

106
Summary
  • Communication is used throughout the reproductive
    process
  • To locate potential mates, signal their identity,
    advertise their qualities as a mate, coordinate
    their physiology, and maintain pair bonds
  • Group-living animals maintain social bonds
    through touch
  • Alarm signals warn of danger and cause receivers
    to flee or assemble
  • Animals communicate about the location of food
    resources
  • Honeybee scouts communicate the direction of food
    with
  • A round dance (for nearby resources) or a waggle
    dance (for distant resources)

107
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