溝通：管道與功能 (Communication: Channels and Functions) -- 動物行為學 (Ethology)...

溝通：管道與功能 (Communication: Channels and Functions) -- 動物行為學 (Ethology)

鄭先祐 (Ayo)

國立臺南大學環境與生態學院生態科學與技術學系教授

Ayo NUTN Web: http://myweb.nutn.edu.tw/~hycheng/

大學部生態學與保育生物學學程 ( 必選 ) 2010 年秋冬

Ayo 教材 (動物行為學 2010) 2

Part 3. 個體間的互動

生殖行為 (Reproductive Behavior) 親代照顧與交配體系 (Parental Care and Mating

Systems) 溝通：管道與功能 (Communication: Channels and

Functions) 溝通的演化 (The Evolution of Communication) 衝突 (Conflict) 團體生活，利他和合作 (Group Living, Altruism,

and Cooperation)


15a 溝通：管道和功能

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

Communication: Channels and Functions

By Goodenough, McGuire, and Jakob


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 ( 偷聽的

風險 ) by rival males and predators


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


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


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


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


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


In many sharks, agonistic displays involve symmetrical depression of the pectoral fins ( 胸鰭 ).

(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.


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 ( 闖入者 ) retreats


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


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


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


(a) stages in the claw-waving display of male uca perplexa. (b) the interval between claw waves, (c) the duration of claw waves

As distance decreases, the interval and duration between claw waves decreases


(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.


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)


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( 拍打 ) the water Woodpeckers drum on trees

Sounds are generated by rubbing appendages together Insects rub parts of their exoskeleton together


Sound production: stridulation ( 唧唧鳴聲 )

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


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


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


concave-eared torrent frog 凹耳蛙（學名： Amolops tormotus ）為蛙科湍蛙屬的兩棲動物，是中國的特有物種。分布於浙江安吉縣和建德市以及安徽黃山，一般棲息于山溪附近。其生存的海拔範圍為 380 至 700米。該物種的模式產地在安徽黃山。


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


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)


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 ( 更格盧鼠 ) 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


Kangaroo rats ( 更格盧鼠 ) Blind mole rats Water striders


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


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


Chemical signals are durable ( 耐久的 )

They remain after the signaler has gone Delineation ( 描繪 ) 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


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 ( 狨猴 ) discriminate familiar from

unfamiliar conspecifics Each female has a unique scent signature (odor mosaic)

based on the ratios of chemicals in the scent mark


marmosets ( 狨猴 ) Common marmosets deposit

scent marks that are complex combination of many chemicals.


A signal’s 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


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 ant’s body to evaluate

chemicals on the other ant’s body To determine if the individual is a colony member or an

intruder Contact chemoreception is associated with nonvolatile

chemical cues


Some animals have organs for chemical communication

Amphibians, reptiles, and mammals may have a vomeronasal (Jacobson’s) 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


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( 怪相 ) (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.


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.


Pheromones ( 費洛蒙 )

Chemicals produced to convey information to other members of the same species

Releaser pheromones have an immediate effect on the recipient’s behavior A female silk moth emits a minuscule amount of her

powerful sex attractant bombykol Males immediately turn and fly upwind to find her


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


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


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


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


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


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


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


A message sent by touch can be varied

By how the recipient is touched ， rubbing ( 摩擦 ), patting( 輕拍 ), pinching ( 擰捏 ) Where the recipient is touched The frequency and duration of touching The extent of surface area touched

Humans send and decode tactile signals


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


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


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


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


(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.


Sternopygus macrurus Eigenmannia virescens Apteronotus albifrons ( 線翎電鰻 )

Sternarchorhamphus macrostomus ( 胸鉤電鰻 )


Rhamphichthys rostratus Gymnorhamphichthys

hypostomus Hypopygus lepturus ( 下

臀電鰻 )


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 sender’s identity

Waveforms are different between the sexes And among different species


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


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


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


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( 震動 ) components: stridulation ( 唧唧鳴聲 ) ,

up and down bouncing of the body, and striking the substrate with mouthparts


Male brush-legged wolf spider


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 sender’s energy Recipients need more energy to receive and process multiple

signals May make senders and receivers more susceptible to

predation


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 ( 求婚 ) It’s adaptive not to mistake heterospecifics for

conspecifics Don’t waste time and energy courting an animal with

whom it is impossible to produce viable offspring Don’t defend a territory from an individual that is not

competing for resources or mates


All sensory channels are used for species recognition Birds use song frequency (which notes are sung) and

syntax ( 語法 ) (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


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?


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 ( 錯誤的選擇 ) 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


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


Female crickets gather on a loudspeaker that broadcasts the male’s courtship song


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


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


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


blue-ring octopuses


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 suitor’s qualities His physical prowess ( 身體能力 ) Ability to provide food for the offspring The extent of his commitment


Female birds assess male quality

Male common terns ( 燕鷗 ) 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)


common terns 燕鷗 wheatears


Communication: coordinationof behavior and physiology

Male and female reproductive systems are not always synchronized Courtship displays can function to coordinate the couple’s

behavior and physiology 範例： ring doves


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 ( 咕咕叫 ) , and her own vocalization stimulates estrogen production.


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 salamander’s courtship

pheromone makes the female more receptive The female indicates her receptivity and the male

deposits a spermatophore


During courtship, a male dusky salamander injects a female with his courtship pheromone.

(a) the male alternately scrapes the female’s 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 male’s tail and straddling his tail.


(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.


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


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


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


Maintaining social bonds in primates

In primates, grooming smooths over tension and restores relationships after conflicts


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 deer’s tail Volatile pheromones that diffuse quickly High-pitched sounds


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


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


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


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


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


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


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


(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.


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


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.

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.


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.


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 sun’s azimuth (the point on the

horizon below it), the hive, and the flower

Dancing bees convey this angle


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


Bees adjust the angle of their dances

To account for the earth’s 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 flower’s location


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.


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


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


Researchers can “talk” to bees

By using a mechanical model of a dancing bee The model’s dance was not as effective as a live bee’s

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


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


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


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


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


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)


問題與討論

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Ayo 台南 NUTN 站 http://myweb.nutn.edu.tw/~hycheng/

溝通：管道與功能 (Communication: Channels and Functions) -- 動物行為學 (Ethology)...

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