Chapter 51: Behavioral Ecology
Behavioral ecology
How behavior develops, evolves, & contributes to
survival & reproductive success
Ethology
Study of animal behavior (in the animal’s natural
environment)
Behavior
What an animal does & how the animal does it
Cause of behavior
Proximate
Environmental
trigger for behavior as well as genetic, physiological, &
anatomical mechanism for the act
“how”
Ultimate
Addresses
“why”
evolutionary significance for behavior
Types of behavior
 Instinct
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Inherited behavior; developmentally fixed
Examples:
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Directional movements
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Kinesis- change in activity or rate in response to a stimulus (ex.
sow bugs more active in humidity)
Taxis- oriented movement toward or away from a stimulus (ex.
Trout face current)
Migration (ex. Migratory restlessness in blackcap birds)
Animal Signals & Communications
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Signal=behavior that causes a change in another animal’s
behavior
Communication= transmission of, reception of, & response to
signals
visual
Tactile
electrical signals
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Chemical
 Releaser Pheromones- cause immediate behavior change
 Primer pheromones- cause physiological change
Auditory
which communication is used is dependant on animal’s
environment & lifestyle
Fixed Action Patterns
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Sequence of unlearned, unchangeable behavioral
acts carried out to completion once initiated
Triggered by sign stimulus (external sensory stimuli)
Ex. Male stickleback fish aggressively defends
territory when triggered by red color
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Imprinting
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Behavior that involves learning & innate
components & is irreversible
Sensitive period: Brief period in which behavior can
be learned (typically from parent)
Ex. Graylag gosling accept any moving object as
mother during 1st 2 days
Learning
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Modification of behavior based on specific
experiences
Habituation
loss of responsiveness to stimuli that convey little or no
information
 “cry-wolf” effect
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Spatial Learning
Modification of behavior based on experience with spatial
structure in the environment (location of nest, hazards,
food, mates)
 Use landmarks as location indicators
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Cognitive maps
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Internal representation/code of the spatial relationships
between objects in an animal’s surroundings
Associate learning
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Ability to associate one feature of the environment
(stimulus) with another (the response it produced)
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Classical conditioning- stimulus is associated with a reward or
punishment
Operant conditioning/trial & error learning- animal associates one
of its own behaviors with reward or punishment
Cognition & problem solving
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Ability of an animal’s nervous system to perceive, store,
process, & use information gathered by sensory receptors
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**Natural Selection can act on behavior that
has a genetic component
Behavioral Variation can exist in
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prey selection
aggressive behavior
Parental care
Migratory patterns
**Natural selection most often acts on
behaviors that increase survival & reproductive
fitness….
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Foraging behavior
Mating behavior & choice
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Foraging Behavior
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Optimal foraging theory
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food obtaining behavior is a compromise between the benefits of
nutrition & the cost of obtaining food
Costs include- energy expenditure, risk of own predation
Examples:
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Northwestern crows flying up to break open shells of molluscs
Bluegill sunfish selecting larger vs. smaller crustaceans
Mule deer feeding in open areas vs. forest edges
Mating Behavior & Mate choice
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Mating relationships
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Promiscuous- no pair bonds
Monogamous- single pair bond; no dimorphism
Polygamous- sexual dimorphism
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Polygyny- one male mating with several females; male ornamented
Polyandry- single female mating with several males; female ornamented
Need for parental care & certainty of paternity influence mating
behavior
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Sexual selection & mate choice
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Intersexual selection
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Female preference for a male mating behavior or anatomy
influences that behavior or anatomical structure’s rate of
occurrence
Female prefer traits that signal male quality/health
Intrasexual selection
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Male competition for mates
Agnostic behavior- ritualized contest that determines which male
gains access to the resource
Game Theory Different strategies effectiveness may vary based on
environment & strategies of other individuals
 Ex. Ispod Paracerceis sculpta alpha, beta, & gamma males;
orange, yellow, & blue throat lizards
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Social Behavior & altruism
 “Selfish” behavior can be explained by natural selection
 Altruism: selflessness; animal behaves in such a way that
decreases its own fitness but increases the fitness of others
in the population
 Examples:
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Belding’s ground squirrel’s alarm call
Worker bee sterility; sting & die
Naked mole rats protecting queen & kings
Inclusive fitness: total effect an individual has on
proliferating its genes through its own offspring or
through a relatives offspring
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rB>C favors altruistic behavior where:
 r= coefficient of relatedness
 B= benefit to the altruistic behavior (average # offspring
that will be produced as a result)
 C= cost of altruistic behavior (average # of offspring that will
not be produced as a result)
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Kin selection
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Reciprocal altruism
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Individual acts to enhance the reproductive success of relatives
improves the chance that genes the same as his/her own are
passed on
Altruistic individual aids a non-relative with “hope” that the favor
will be returned in the future
Found most often in highly social species in which “cheating”
would lead to negative consequences
“tit for tat”
Social Learning
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Learning through observing others
Culture: system of information transfer through
social learning or teaching of individuals in a
population
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Example: Vervet monkey alarm calls
Sociobiology: study of human culture & its
relationship to evolutionary biology