What is communication? Classical definitions “an action on the part of one organism (or cell) that alters the probability pattern of behavior in another organism (or cell) in a fashion adaptive to either one or both of the participants” – Wilson, 1975 “Any sharing of information” – Smith, 1984 “The transmission of a signal from one animal to another such that the sender benefits, on average, from the response of the recipient” – Slater, 1983 Possible outcomes of communication 1. Mutual benefit – true communication 2. Sender benefits – manipulation/deceit 3. Receiver benefits – eavesdropping 4. Neither benefits – Highly unlikely • Communication isn’t cheap • Is the ability to pay the COST part of the MESSAGE? Levels of Communication 1. Vegetative 2. Tonic 3. Phasic 4. Signal Level (biosocial & psychosocial influences) 5. Symbolic (develops through social experience) 6. Language (abstract) Signals The receiver must be able to discriminate a signal from other background stimuli (signal to noise ration) Between species – prevention of hybridization Within species – important to minimize confusion between conspecifics Individual differences – individuals can be accurately identified Modalities for signal production and reception 1. Mechanosensors (ex. hearing, touch) 2. Photoreception (ex. UV vision in insects) Modalities for signal production and reception 1. Chemoreception (ex. pheromones in moths) Modalities for signal production and reception 1. Electroreception (ex. many species of fish) Signal Function Mate attraction Honest (ex. white crowned sparrow dialects) Dishonest (ex. blue gill sunfish) female on bottom, mating male above; female mimic & “sneaky” male above Signal Function 1. Parent-offspring interactions Begging Kin recognition (ex. mexican free tailed bats) 2. Social integration 3. Autocommunication (ex. echolocation) 4. Signals about the environment (ex. Alarm calls in Beldings ground squirrels) 5. Conflict resolution The evolution of communication RITUALIZATION Signal behavior is established or improved in such a way that it becomes a more efficient means of communication Via “bricolage” the source can be virtually any trait including (especially?) autonomic reflexes Ways to elaborate displays 1. Development of conspicuous structures 2. Rhythmic repetition 1. Intensity 2. Exaggeration of certain component 3. Omission 4. “Freezing” 5. Change in sequence 3. Change in speed of performance 4. Change in vigor Key aspects of Ritualization Intention movements Displacement activities Redirection activities Secondary modifications (e.g.: intention movement to threat to courtship) Development of conspicuous structures and further correlation of the movement with the structures Schematization of the movement Exaggeration of certain components Changes in absolute and relative thresholds of components Changes in the coordination of the components Emancipation- pattern comes to be governed by causal factors other than those which governed it originally. An interesting system – Mexican free-tailed bats Mexican free tailed bats roost in caves in Texas, where maternity colony size sometimes reaches 20 million When a mother goes to forage she leaves her pup in a creche which may contain up to 4000 pups per square meter. What’s the problem? When a mother returns to the roost she must be able to identify her own offspring A pup will feed from any female For many years it was believed mothers do not discriminate between pups What’s really going on? Females first use spatial cues Pups are constantly vocalizing (sending signals saying “FEED ME!”) Females then listen for a specific vocalization that her pup gives, called an isolation call Olfactory signals also play an important role BIRD COMMUNICATION Song bird model is the most studied – involves fixed and flexible components and shows inherited, developmental and experiential influences [more] The End!
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