Chapter 5Control of Behavior

(1st lecture)

Early ethologists studied simplebehaviors that appeared in nearly

complete form the first time they wereperformed, and were usually elicited by a

simple cue of some sort. They called these behaviors Fixed Action Patterns.

Greylag goose retrieving an egg that had rolled out of its nest.Once the retrieval behavior has begun, the goose will complete

the action, irrespective of whether the egg has rolled away from its bill.

Illustration of a young gull begging for food fromone of its parents

The chicks peck at the red spot on the lower bill.All young gulls instinctively peck at this spot.

In so doing, they stimulate the parent to regurgitate food for them.Without the pecking, the parent would never feed the chicks.

What elicits the pecking response?

It turns out that a simple model, which enhances specific featureof the stimulus, is more effective at eliciting the behavior

than a model that resembles a gull parent

This simplemodel wascalled a signstimulus

Another example of a sign stimulus,as revealed through the use of simple models

Typical male three-spinedstickleback during breeding

season. His presence normally elicits aggression in conspecific

males

However, it turned out that models with a red underside

were more effective at eliciting aggression than was the male

lacking a red underside

Flow diagram showing early ethological conceptsof the mechanisms involved in a simple behavior

pattern such as egg retrieval or bill pecking

Do humans express fixed action patterns?

Yawns are very similar in appearance no matter who is doing the yawning.

They last about 6 sec, are difficult to stop in mid-performance, and are infectious, releasing yawns in other humans that observe (or hear) the yawner.

Tinbergen’s original definition of a FAP:an innate behavior pattern that is

stereotypedspontaneous

independent of immediate controlgenetically encoded

independent of individual learning

Later studies found that this strict definitiondid not apply neatly to any behavior

Many bats literally seewith sound, using biosonar

How is this possible?

see the following website:http://www.biosonar.bris.ac.uk/

Moth ears contain 2 auditory cells, called the A1 and A2 cell

How to flying insects like moths cope with the persistentthreat of bat attacks?

The A1 and A2 cell each have different response properties

The A1 cell respondsto low-intensity bat

calls, and increases its firing rate in response

to louder calls

The A2 cell respondsonly to high-intensity

bat calls

Note that these auditory cells cannot discriminate between calls that range in frequency between 20 and 100 kHz

Neural records of how the A1 and A2 cells in each earresponse to low- and high-intensity bat calls

Responseof A1 cell tolow-intensity

bat call

Left ear

Right ear

Response ofA1 + A2 cells

to high-intensitybat call

A2 cell !

!! ! !

Activation of A1 cells produces different behavioral responsethan activation of A1 + A2 cells

Stimulation ofA1 cell causesmoth to veeraway from bat

Stimulation ofA1 + A2 cellscauses moth tomake a powerdive

Sensory input fromA1 and A2 cellshave direct but

distinct pathways to flightmuscles (via severalinterneurons in CNS)

Some moths have evolved mechanisms for determining the locationof approaching bats, which resemble those used by owls to locate prey