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Photo Copyright R. Hays Cummins

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1 Photo Copyright R. Hays Cummins
Communication Chapter 12 Photo Copyright R. Hays Cummins

2 Communication What is communication? How signals convey meaning
Types (traits vs. behaviours), classification How signals convey meaning Channels of communication (methods) Functions of communication (purposes) Complex Communication (bee dance)

3 Types of Communication
What is Communication? Definition Types of Communication Behaviours (‘signals’) States/ Traits How is Communication Classified? Categories of Interaction (Wiley) Other views

4 What Is Communication? In biology, defined as:
The transfer of information from one molecule, cell, or organism to another, as by chemical or electrical signals or by behaviours. (www.dictionary.com) All communication involves a “sender” and a “receiver”

5 Biological Communication
Signal: The physical form in which a message is coded; any behaviour pattern that communicates something Discrete vs. Graded Discrete: “All or none” (e.g., FAPs) Graded: Varying in intensity and/or frequency; provides info about the strength of stimulus (e.g., Betta splendens display)

6 Discrete signal (ear position)
Graded signal (mouth) Increasing intensity

7 Biological Communication
Displays are one type of signal Display: Any behaviour pattern especially adapted (i.e., modified through evolution) in physical form or frequency to function as a social signal in communication e.g., spruce grouse males beating wings on air e.g., male dominance mounting in dogs

8 Two male Betta splendens showing fin flare and operculum (gill) flare
Communicates willingness to fight; allows assessment of opponent without combat/injury

9 Wiley (1983): Categories of Interactions
Terms used to describe interactions, depending on the value of the info to sender and receiver Value of info to RECEIVER Value of info to SENDER: positive zero (negative) “True communication” “Manipulation” (“deceit”) “Eavesdropping” (“exploitation”) “Ignoring” (“spite”) +/+ +/0 +/- 0/+-/+ 0/ /-

10 Biological Communication
How to classify/define communication? Value of information to each participant Cost & Benefit Analysis Both benefit = true communication; male bird song during mating season Sender benefits, receiver is unaffected or harmed = deceit or manipulation; e.g., killdeer performing “broken wing display”

11 Biological Communication
® Disney, Finding Nemo Deceit Interspecific deceit more common predator-prey relationships Aquatic predators that attract prey using lures that look like insects Intraspecific “deceit” unlikely to spread in a population, except…

12 Categories of Interactions
Sender benefits, receiver is harmed (+/-): Deceit Another example: “femme fatale” fireflies – females pretend to be receptive, attract and consume males of another species Sometimes the receiver is actually harmed. This is what Wiley labelled as deciet. For example, the female send out signals that attract the male to come and mate with her, then she eats him. The male dies, but could be said to benefit indirectly in that his genes are passed on, so this is a tricky one. Batesian mimicry can sometimes be considered deceit in that the predator wastes energy in initial pursuit of the prey, then retreats, such as a bird pursuing a caterpillar that then inflates its posterior to look like a snake and scares the bird away.

13 Biological Communication
Value of information to each? Cont’d Sender unaffected or harmed, receiver benefits = exploitation or eavesdropping; mouse rustles grass as running, allowing owl to hear it, catch it & eat it Neither benefit, both may be harmed = ignoring or spite; a bird ignores the cryptic colouration of a moth and tries to eat it Monarch Butterfly

14 Biological Communication
Other ways to view communication: Communication need not benefit both sender and receiver since natural selection operates mainly at the level of the individual (Dawkins & Krebs); Displays evolve to “waste” a minimum of energy of sender… persuade the receiver, not “inform” (exaggeration and redundancy of signals); roar of male lion

15 Biological Communication
Other ways to view communication: Displays – have evolved to maximize the effectiveness of information transfer, to the benefit of both sender and receiver coevolution of signals; each species acts as a strong selection force on the other; Problem: this definition cannot encompass “lying”

16 How Signals Convey Meaning
Distance & Duration (signal type) Can travel far (e.g. scent), or operate over short distances (e.g., visual signals) Can be long-lasting (e.g., pheromones entire breeding season) vs. short-term (e.g., calls/ vocalizations)

17 How Signals Convey Meaning
Individuals can increase information content of signals by… combining 2+ signals = composite signal Zebra: meaning of “open mouth” signal depends on ear position (forward = friendly; backwards = hostile) …changing syntax, or sequence of displays A before B is NOT = B before A

18 How Signals Convey Meaning
Information in a signal can be context-dependent; E.g., “lion’s roar” : aggressive, maintaining contact with pride members, or indication to neighbours to keep a good distance

19 Types of Communication (How can a message be sent?)
States or Traits: Sign stimuli – Ch.’s 2 & 10 Aposematism & Batesian mimicry – Ch. 15 Indicator traits – Ch. 17 (to come) Behaviours: (i.e., “does”) Signals Some FAPs Displays Communication can be broken down into different types. This isn’t quite clear from your textbook, but I find it helpful to think of types of communication in terms of whether they are a “state” or trait, or a behaviour. For the states/traits, some of these you have encountered in earlier chapters.

20 Sign Stimuli Three-spined stickleback (Ch. 2, p. 15)
Enlarged belly of female = Sign stimulus (honest sign that female is ready to spawn)

21 Sign Stimuli Not a behaviour, a state (e.g., enlarged belly)
May provide info about physical state of bearer NOTE: Not all sign stimuli convey information, and not all FAPs act as signals E.g., egg retrieval in gulls If info is exchanged between conspecifics when sign stimulus or FAP occurs = communication

22 Aposematism (warning colouration)
Conspicuous markings of noxious animals are easily recognizable and avoidable by predators Convey information about unpalatability Batesian mimicry = manipulation/deceit (lying) Aposematism is another example of a type of communication that involves a state or trait. In this case, the warning colouration or marking of a species communicates to predators that it is unpalatable or toxic. Batesian mimicry is also a type of communication, however, rahte than being an honest signal of unpalatability, it is in effect lying or deceiving as predator into believing that the prey is toxic. pinker.wjh.harvard.edu/ photos/santa_barbara_c...

23 Communication What is communication? How signals convey meaning
Types (traits vs. behaviours), classification How signals convey meaning Channels of communication (methods) Functions of communication (purposes) Complex Communication (bee dance)

24 Channels of Communication
Odour Sound (ultrasonic, sonic, and infrasonic) Seismic vibrations Touch Electric field Visual The physical form used to transmit the signal from sender to receiver. The form in which a message is transmitted. Think “method of transmission” or “modality”

25 Properties of Sensory Channels
Range (distance covered) – short to long Transmission rate (how long does it take to get from sender to receiver?) – slow to 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? – slow to fast) Locate sender? (easy to difficult) Cost to send signal (low to high) Complexity of message (low to high) When comparing the usefulness of 2 different channels, these properties are thing to consider. These are just some things you want to consdier when compareing the various sensory channels.

26 Audition: Properties Auditory communication Range?
long Travels around objects? Yes Useful at night? Fade-out time? Fast Cost to sender? High

27 Odour Used by most species (evolutionarily “old”)
Usually involves pheromones: a species-specific odour cue released by animals that influences the behaviour and/or physiology of conspecifics Priming pheromones produce a generalized response such as triggering estrogen and progesterone production that leads to estrus, while signaling pheromones produce an immediate motor response, such as the initiation of a mounting sequence.

28 Odour Functions: Group spacing – marking territories
Recognition – identifying conspecifics, kin, individuals Reproduction – attracting mates, altering physiology (e.g., levels of sex hormones) Alarm – fear pheromone (e.g., inverts)

29 Odour Pheromones often present in urine of mammals (& anal glands)
Two types: priming (generalized response) signaling (immediate specific response) “Flehmen” response (vomeronasal organ) Territories = group spacing Mate attraction = reproduction, also ovulation receptiveness, etc.

30 Odour: Properties long range slow transmission rate
travels around objects useful at night slow fade-out time low cost to sender unable to locate sender simple message only (unless within a territory)

31 Sound Can occur within or outside of human “umwelt” (~20-20,000 Hz)
ultrasonic (high frequency - e.g., echolocation) infrasonic (low frequency - e.g., African elephant rumbles, whale song)

32 Sound Can be produced by: stridulation (e.g., cricket “chirp”)
a single organ (vocalizations) stridulation (e.g., cricket “chirp”) other means (e.g., drumming by Northern Flickers/ woodpeckers)

33 Seismic Vibration Substrate-borne vibrations detected by animals
White-lipped male frogs make thumps, females extremely sensitive to vibrations Spiders catch prey by detecting vibrations Male orb-weaving spiders “pluck” at web to bring female out for mating

34 Sound/Vibration Properties
long range fast transmission rate travels around objects useful at night fast fade-out time high cost to sender may be able to locate sender sound = complex message, vibration = simple message

35 Touch Tactile communication (physical contact)
Common in invertebrates: Antennae, tube feet, etc. (also pick up chemical cues) Vertebrate copulation  tactile stimulation elicits lordosis response in female mammals Touch (e.g., vaginal stimulation) can induce ovulation in some species (induced ovulators)

36 Touch: Properties short range fast transmission rate
can’t travel around objects useful at night fast fade-out time low cost to sender easy to locate sender Simple message only

37 Visual Communication Markings, patterns, colour require vision
Mostly used by diurnal species (visual displays), e.g., aggressive displays of SFF Exception: fireflies species-specific flashing to attract mates and during courtship “femme fatales” of Photuris versicolor (deceit)

38 Vision: Properties medium range fast transmission rate
can’t travel around objects little use at night fast fade-out time cost to sender medium easy to locate sender allows complex messages

39 WhoZoo(http://whozoo.org) Electric Field Some sharks and electric fish detect prey’s electric field using electroreceptors Strongly electric fish (e.g., electric eel) have EODs (electric organ discharges of 100’s V) Social communication possible by altering wavelength/ pulse duration

40 Electric Field: Properties
short range fast transmission rate travels around (and through) objects useful at night/in murky water fast fade-out time cost to sender varies easy to locate sender Simple message only

41 Functions of Communication
Group spacing & coordination Recognition Reproduction (identifying/attracting mates) Agonism and social status Alarm (warning) Finding food Soliciting play Giving & soliciting care Synchronization of hatching

42 Functions of Communication
Group Spacing & Coordination Spacing signals of primates: Distance-increasing (branch shaking) Distance-maintaining (dawn chorus) Distance-reducing (contact/lost calls) Proximity-maintaining (social grooming)

43 Functions of Communication
Recognition Species Recognition Neighbour Recognition Individual Recognition Kin Recognition

44 Functions of Communication
Reproduction Courting displays, copulation- allow assessments of species, physical condition, “quality” of mate

45 Indicator Traits (Sexual Selection – Ch. 17)
Provide info to members of the opposite sex about the physical condition of the bearer Choosier sex (usually females) show preference for most extravagant traits E.g., brightest colours, largest antlers, longest tail feathers, etc.

46 Keeping signals HONEST:
Zahavi & Zahavi’s “Handicap Principle” If signals are costly to produce (peacock tail), they tend to be honest indicators of condition or ability (i.e., in good health, well-nourished and free of parasites) (sexual selection)

47 Functions of Communication
Social Status/ Agonism Dominance/submissive displays- avoid costly fighting Traits may also indicate social status (bigger, stronger males perceived as dominant) e.g., antler size in moose wolves and dogs

48 Functions of Communication
Female Belding's ground squirrel (Spermophilus beldingi) emitting an alarm call. (Sherman) Alarm Altruism or Selfishness? Alarm calls are given to warn other individuals about the presence of a nearby predator and are usually directed toward close kin. giving an alarm call increases the chance that the predator will attack the caller

49 Functions of Communication
Alarm Vervet monkeys: Seyfarth & Cheney “semantics”- different calls for different predators (avian, ground) Pheromones as chemical alarm substances inverts; mammals Sea urchins steer clear of an area where a urchin has just been crushed

50 Functions of Communication
Finding Food “Information Centre Hypothesis” colonial organisms (e.g., communally roosting weaver birds) hunting packs (African wild dogs) Giving/Soliciting Care, Play; Synchronization of Hatching (precocial birds – vocalize prior to hatching)

51 Evolution of Displays Communicative displays are believed to have evolved from noncommunicative behaviours through the process of ritualization: Ritualization = Evolutionary process by which behaviour patterns become modified to serve as communication signals.

52 Ritualization (example)
Food calling behaviour still seen in roosters may be evolutionary origin of courtship display seen in peacocks i.e., peacocks’ ancestors may have performed food-calling behaviour, which became ritualized into bow/feather spread display presently used

53 Evolution of Displays “freezing” of movement into postures
Stereotyping of behaviour (stays constant even under different levels of motivation) Development of conspicuous body structures- enlarged claws (fiddler crab), ornamental feathers (peacocks, male ducks), manes (lion), exaggerated fins (Betta) Crested Auklet (I. Jones)

54 Displays may have arisen from…
Intention movements - e.g., “powk” calls of BL Kittiwakes -- gannets OR Displacement activities- innate, stereotypical responses to stimuli that seem inappropriate to the situation Some degree of conflict in organism’s motivation- e.g., strange female approaches: is a sexual or agonstic response needed?

55 Displacement Activities
Evolved into courtship display: During courtship, males may preen or touch own feathers (sham preening) Conspicuous feathers (sailfeathers) may have evolved and are exposed during this behaviour Mandarin Duck

56 Other origins of displays:
Receiver bias - the increased sensitivity of perceptual systems to certain stimuli as a result of natural selection Such biases may influence the evolution of communicative displays E.g., insect feeds mostly on yellow flowers, adapted to be sensitive to yellow in general, males with yellow are preferred, and may exploit this to attract females

57 Complex Communication

58 Honeybee communicative dances
“Round Dance” Food nearby; less detailed “Waggle Dance” Food >200m away; more detailed

59 Ceiling of hive = direction of sun (reference)
Photo Caption: Diagram of the honeybee dance. (Credit: P. Kirk Visscher.) Ceiling of hive = direction of sun (reference) Angle of straight run (on vertical) = direction of food source relative to sun

60 direction and duration of the straight run is critical
antennae of hive members maintain contact with the dancer and taste samples of regurgitated food


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