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Published byClyde Spencer Modified over 8 years ago
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An intended transfer of information from one organism to another. Purpose of communication: Location/position (food, sex, lost) Advertisement (quality quantity health) Defense (recruiting assistance, threatening, intimidating) Offence (tactical information for group hunting, herding prey) Social intent (dominance fear need help) Modes of communication: Chemical (olfactory, taste, Hormonal??) Visual (body language, plumage, skin pigmentation, physical augmentations) Auditory/mechanosensory (can be sub to ultrasonic) Vocalizations (songs, calls, barks, whistles etc.) Non vocal (stridulations/vibrations) Electric Communication
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Modes of communication: Chemical (olfactory, taste, Hormonal??) Visual (body language, plumage, skin pigmentation, physical augmentations) Auditory/mechanosensory (can be sub to ultrasonic) Vocalizations (songs, calls, barks, whistles etc.) Non vocal (stridulations/vibrations) Electric
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Senders and receivers of communications Intraspecific: within species Interspecific: between species Honest communicators Dishonest communicators (eavesdropping and lying) Predators Competitors Communication Given that communications can be exploited/misinterpreted how should evolution act on communication systems? Clear signals to intended receiver Cryptic signals to everyone else
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Foraging Atta cephalotes Leaf-cutter ants Use chemical and subsonic communication to indicate food source and quality Chemical signal: methyl 4-methylpyrole-2-carboxlate 1 milligram of this pheromone properly laid down could lead a column of ants around the earth… 3 times Leaf-cutters only select younger leaves Fewer secondary compounds such as protease inhibitors and defensive toxins More sugar Selected leaves are striped to the stalk, the rest are left untouched
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Foraging As the worker cuts a section of the leaf it will stridulate with its gaster Causes a vibration that recruits other workers to the leaf Also attracts Minim-workers Study1: Tough vs tender leaves that were sweetened vs not Percent stridulating by treatment: 40% tough 70% tender 100% sweetened Study2: Choice test between vibrating and silent leaves Workers preferred vibrating leaves
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Mating and social dominance There are a variety of electric fishes each has a species-specific discharge pattern that is generated by the electric organ Used for: Stunning prey Stunning predators Communicating Carl D. Hopkins Some species can produce up to 600 volt discharges
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Mating and dominance: Electric fish Electric fish can both produce electrical currents and detect electrical fields This forms the basis for communication
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Mating and social dominance: Electric fish Males during breading season will produce longer discharge pulses In the presence of females discharges increase in frequency&duration Males exposed to androgens will produce longer discharge pulses When in groups social rank of males is determined by pulse duration These rankings can be a priori predicted based on ketotestosterone levels.
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Ritualized battle safely establishes dominance (usually) These battles establish dominance using honest signals Size Strength Health Commitment to win
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Raven yelling establishes dominance
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Mating and social dominance: Ravens
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Dishonest signals Used by predators and prey to deceive opponents Within species can be used to deceive reproductive opponents
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