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Animal Communication: Introduction and Evolutionary History
ZOL 313 June 3, 2008
Animal Communication: Introduction and Evolutionary History
ZOL 313 June 3, 2008
Objectives:
1. Become familiar with different sensory modes of animal communication and be able to generate hypotheses and predictions.
2. Understand how sensory exploitation may have influenced the evolution of communication signals in animals.
Communication:
Modes of animal communication:
Visual
Auditory
Tactile
Chemical/Olfactory
Other (Electric, Sonar, etc.)
Hypothesis:
Visual Communication
Signalers: Fruiting plants
Receivers: Birds (blackcaps)
Prediction:
http://news.bbc.co.uk/2/hi/science/nature/7219803.stm
Visual CommunicationExample:
Who are male birds singing to?
Auditory Communication
Hypothesis 1: Rival repulsion
Prediction:
Who are male birds singing to?
Auditory Communication
Hypothesis 2: Mate attraction
Prediction 1: Females will respond more strongly
Prediction 2: Male song will increase
Example: Social Grooming
Tactile Communication
Functions of social grooming:
Pheromone: a chemical that triggers a natural behavioral response in another member of the same species
Chemical/Olfactory CommunicationHypothesis:
Prediction:
Chemical/Olfactory Communication
Hypothesis: Squirrels rub snake skin scent on themselves
Prediction:
“Other” Modes of Communication
Example: Weakly electric fish
Example: Spotted hyena greeting behavior
Combination of Sensory Modes
Why do female spotted hyenas have a psuedopenis?
Costs:
Benefits:
Rapid-flutter wing-waving
Pelicans
Pre-takeoff Sky-pointingAlternate wing-waving
Slow wing-waving Throwback
Gannets Boobies Anhingas Cormorants
Pre takeoff
Wing waving
Both wings waved
Rapid wing-waving
The Evolution of CommunicationExample:
Example: Whistling moth males
The Evolution of Communication
How did they evolve ears to hear this signal? Ancestral State:
Saturnid moths have mechanoreceptor cells that carry information
Whistling moths have similar anatomy but
A whistling moth ancestor may have had mechanoreceptor cells that gave it
Ancestral signals can be co-opted for a new function.
The Evolution of Communication
Example: Whistling moth ear probably was first adaptive in detecting
Example: Some bowerbirds co-opted an aggressive signal
Sensory exploitation: a situation where a signaler is able to tap into a preexisting sensitivity or bias in the perceptual system of a receiver
The Evolution of Communication
Example:
Female “net stance” may have evolved first as predatory behavior (N).
Example:
The Evolution of CommunicationSensory exploitation: a situation where a signaler is able to tap into a preexisting sensitivity or bias in the perceptual system of a receiver
Hypothesis: Female guppies originally were attracted to orange spots
Prediction: Females with stronger preferences for males with orange spots
Sensory preferences can exist in current species that have never encountered a particular signal before.
The Evolution of Communication
Example: Female X. maculatus fish
Sensory preferences can exist in current species that have never encountered a particular signal before.
The Evolution of Communication
Hypothesis:
Prediction:
The Evolution of Communication
Sensory preferences can exist in current species that have never encountered a particular signal before.
Zebra finches do not have crests. Neither do their close relatives
1. Does this experiment support the hypothesis that female zebra finches have a sensory preference for a novel signal? Why/why not?
2. From this experiment, what color feathers (white, red, green, or all three) would you guess female zebra fiches use to line their nests and why?
Sensory “exploitation” does not mean responding to the signal is maladaptive for the receiver.
The Evolution of Communication
For example, female that responded positively to males with an exaggerated signal could have gained fitness for several reasons, such as:
1.
2.
