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:

Visual Communication Example:

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 Communication Hypothesis: 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-takeoffSky-pointing Alternate wing-waving Slow wing-waving Throwback GannetsBoobiesAnhingas Cormorants Pre takeoff Wing waving Both wings waved Rapid wing- waving The Evolution of Communication Example:

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 Communication Sensory 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.