Animal Communication: Introduction and Evolutionary History ZOL 313 June 3, 2008.

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.