Behavioral Ecology
Chapter 55
Background and early studies
What is behavior?
• The way an animal responds to stimuli in its environment
• Behavior is a pattern of responses to a stimulus
How can we explain behavior?
• How it works physiologically
 Proximate answer
• The adaptive value of the behavior
 Ultimate answer
• So, behavioral scientists study what behavior an organism does, how it does it
and why it does it.
Behavior
•
Behavior is influenced by both genetic and environmental factors (behavior is
an expression of genetic and environmental cues)
 Nature versus nuture argument
 Gene by environment interaction is important
Genes and behavior
• Almost all behavior has a genetic basis
• So, behavior is subject to evolution through natural selection!
• Behavior is essential to understanding an animal’s evolution and ecological
interactions
History of behavioral ecology
• Konrad Lorenz--imprinting and instinct
• Karl von Frisch--honeybee dances & communication
• Niko Tinbergen--gull behavior and learning+instinct
• All three shared Nobel Prize in physiology/medicine in 1972
Konrad Lorenz
• Imprinting – learning that is limited to a specific time period in an animal’s life
and that is generally irreversible
• Critical period (sensitive period)– a limited phase in an individual animal’s
development when learning of particular behaviors can take place
Filial imprinting
Konrad Lorenz
• Wrote book “On Aggression” where he asserts that human aggressive
impulses are to a degree innate, and draws analogies between human and
animal territorial behavior
 These assertions have engendered considerable controversy
Karl von Frisch
• Honeybees communicate:
 Direction to food source
 Distance to food source
 Quality of food source
Two types of dances
• Round dance
• Waggle dance
Distance to food source
• The orientation of the straight run in the waggle dance conveys the direction of
the food source, relative to the position of the sun
Distance to food source
• The duration or tempo of the straight runs conveys the distance between nest
and target: Dance tempo slows down with increasing distance to the food
source. The farther away the target, the longer the straight run part of the
dance
Quality of food source
• The intensity of the dance conveys the quality of the food source
Robot bees
Tinbergen - gull feeding behavior
Gull feeding behavior
Learning
• This related experiment with artificial beaks shows learning by gull chicks
Tinbergen
• Published famous paper on the 4 questions in behavioral biology
Tinbergen’s four questions
Tinbergen’s four questions
Tinbergen’s four questions
1) Mechanisms
 Genetic
 Hormonal
 Physiological

In grouse, males begin to exhibit mating behaviors when sex hormones rise
Tinbergen’s four questions
2) Development
 Instincts
 Learning
 Instincts x learning

In grouse, females seem to learn mate choice from their mothers
Tinbergen’s four questions
3) Adaptiveness
 Survival
 Reproduction

Male grouse that attract the most females have higher reproductive
success. However, display is costly to survival
Tinbergen’s four questions
4) Phylogenetic history
 Development of behavior through ancestry
 The grouse family generally shows this mate choice behavior, where males
are elaborate
Development of behavior
Innate or instinctive behavior
• Performed without having been learned
• Usually triggered by simple sign stimuli
• Response to the stimulus is a stereotyped motor program (hard-wired)
 Preset paths in nervous system
Innate behaviors
• Innate behaviors are developmentally fixed
• Not completely genetic, as a physical environment is necessary for the gene to
be expressed
• The key to innate behaviors is that they are expressed under a wide variety of
environmental conditions
Instinctive behavior
• Sign stimuli are often nonspecific
• Innate releasing mechanism - a neural component of the organism that
provides the motor program
• Fixed action pattern – a sequence of behavioral acts that is essentially
unchangeable and usually carried to completion once started
Instinctive behavior
• When a goose sees an egg outside the nest (sign stimulus), it begins a
repeated movement of dragging the egg with its beak and neck
Stickleback
• Male stickleback fish will attack anything with a red underside
Supernormal stimuli
• Given a choice, animals respond to a larger stimuli than a smaller one
Supernormal stimuli
Behavior is genetic
Genetic basis of behavior
• In some cases, single genes control behavior
Adaptive behavior
• Behavior that promotes reproductive success
• Frequency of individuals expressing this behavior will be maintained or
increase in successive generations due to natural selection
Learning influences behavior
• Animals alter their behavior as a result of previous experiences, which is
learning
 Feeding in gull hatchlings
Types of learning
• Nonassociative learning
 Does not require an animal to form an association between 2 stimuli or
between a stimulus and response
Habituation
• A type of nonassociative learning
• An individual learns NOT to respond to a stimulus that has neither good nor
bad consequences
• Pigeons in cities learn that people are no threat and do not flee from them
• Deer become increasingly tame in parks
• Ability to ignore signals is adaptive
Types of learning
• Associative learning
 Requires an association between 2 stimuli or between a stimulus and
response
 Behavior is “conditioned” through the association
 Two major types:
 Classical conditioning
 Operant conditioning
 Differ in the way associations are established
Classical conditioning
• Pair presentation of two different stimuli causes association between the two
stimuli
• Also called Pavlovian conditioning
Operant conditioning
• A behavior becomes associated with its consequences
• “Trial-and-error” learning
What type of conditioning is this? What has the coyote learned?
Instinct and learning
• Innate predispositions toward forming certain associations
 Pigeons can learn to associate food with colors, but not with sound
• Learning is possible only within the boundaries set by instinct
• In nature, adaptation by learning is important to survival
Spatial learning
• Through experience with an environment, an organism creates a mental map
• Birds remember the location of thousands of places where they have stored
food
Animal Cognition
• Do animals other than humans possess cognition?
 Cognition - the ability of an animal’s nervous system to perceive, store,
process, and use information gathered by sensory receptors
 In other words, do they process information in a way that suggests
thinking?
Insight Learning
• An animal solves a problem without trial-and-error attempts at a solution
• Captive chimpanzees show insight learning when they solve a novel problem,
as when they stack boxes to reach food that is out of reach
Instincts and learning
• Instinct = behavior exhibited without feedback from environment
• Learned behavior = behavior that can be altered in response to information
acquired from environment
• Instinct and learning are not exclusive - they can interact!
Innate song
Bird Song: Instinct + Learning
• Bird comes hard-wired to listen for certain acoustical cues; instinctively pays
attention to particular sounds
• Genetic template guides birds to learn the appropriate song
• Which dialect the bird sings depends on what song it hears
•
•
Exposed to own species song during development
Not exposed to song
New information shows that social interaction may override the genetic template!
Importance of social interactions