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Communication. Transfer of information from a signaler to a receiver (c ooperative or non-cooperative?) Any physiological, morphological or behavioral display Perceived by sense organs of another animal Must results in a change in receiver ’ s behavior. Information.
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Communication • Transfer of information from a signaler to a receiver (cooperative or non-cooperative?) • Any physiological, morphological or behavioral display • Perceived by sense organs of another animal • Must results in a change in receiver’s behavior
Information • Identity - species, deme, kin, pairs, individuals, neighbors, class or social status • Ability or condition - contest, signal to predator, potential to mate, ability to mate • Intention - aggression, submission, soliciting care or play • Environment - alarm call, food
Kin recognition Mechanism • Association non-aggressive if reared together, aggressive if reared apart • Phenotype matching • MHC glycoprotein
Selecting forces on the form of signals • Species anatomy & physiology • Species behavior • Environment • Ecological constraints - frequency window
Legitimate signalers/receivers • Intraspecific interaction • Signals between parents and offspring • Distress calls • Begging calls • Following commends • Aggressive signals
Defensive interaction • Warning signals (coral snake, bee, rattlesnake) • Feeding deterrent (monarch butterfly) • Aposematic coloration • Flower – Pollinator • Color, odor, shap
Illegitimate signalers • Misinformation • Batesian mimicry – harmless species that mimic warning signals of dangerous species • King snakes mimicking coral snake • Flies mimicking bees • Burrowing owls mimicking rattlesnakes
Batesian mimicry Evolution 47:277-235, 1993 • Coral snakes and their mimic • Question: • Do color pattern of coral snakes function as warning signals? • Do even imprecise non-venomous mimics experience reduced predation?
Warning coloration & mimicry • Experimental approach – plasticine replicas • Can be employed in large number • Retain evidence of predatory attack • Study conducted in Costa Rica • Replicas placed out on transect • inspect at regular intervals for “injuries”
Illegitimate signalers • Aggressive mimicry – animals that mimic sexual signals of other animals to attract those animals as prey • Fireflies, angler fish • Intraspecific deceit – animals that transfer misinformation to members of own species • Bluff display
Nest parasites, e.g. brown-headed cowbirds • Rove beetles lay eggs in ant nest • Mimic of cleaner wrasses
Illegitimate receivers • Interception of signals • E.g. tungara frog: whine-chuck • Bats are attracted to frog calls • Bats prefer whine-chuck to whine alone • Tendency of males to produce whine-alone calls increase with intensity of predation
Evolution of maladaptive behavior • Novel environmental hypothesis – change of environment • Sensory exploitation hypothesis • Cost << benefit • Risk of being exploited is very low • Response to signals has a clear adaptive value
Mobbing calls vs. “seet” alarm calls in great tit • Mobbing call – 4.5 kHz, easily located, join mobbers in the harassment of their mutual enemy (perched hawk) • Seet alarm call – 7-8 kHz, rapid attenuation, warn mates and offspring of possible danger (flying hawk) • Convergent evolution in the seet calls
An. Beh. 55:511-518, 1998 • Red squirrels: 5 types of calls: rattle, screech, growl, buzz, bark • 1-4: territorial or agonistic, three types of bark: seet, seet-bark, bark • Three types of predator: human, dog, model or natural birds • Results: Bark when human or dog, seet or seet-bark when birds
Sematic or referential information? Low cross-taxon mistake may indicate referential information • Complexity of environment and diversity of escape response to different predator may affect the evolution of alarm call
An. Beh. 55:529-536, 1998 • Heterospecific alarm call • Yellow-bellied marmot and golden-mantled ground squirrel respond to conspecific and hetero-specific alarm call more than to wren calls • Responses: stop feeding, running, raise their head and scanning • Maintain anti-predator and vigilance longer during 30-sec playback and post-playback periods
Sensory preference • Sensory exploitation hypothesis • Female preference evolves before male traits • Coevolution hypothesis • Female preference evolves with male traits