4. Foraging Flashcards
what is the search image theory
As a forager increasingly encounters a particular prey, the ability to recognize the prey increases
what are ways for animals to recognize prey easier
Development of mental/sensory representation of prey; Response to cryptic prey; Search image may be linked to salient feature of prey or representation of entire prey item; new prey items is ignored until it becomes more prevalent
which animals were used to test finding food and search image
blue jays pecking at cryptic moths
what are three traditions of decision making research
economics, psychology, and ecology
what does the classical optimal foraging theory assume
assumes that evolution has favored foraging strategies that maximize the rate of energy intake as a proxy of Darwinian fitness
what are the assumptions in the economic models
rational choice, self interest, stable preference over context and time
what is utility
utility is the degree of liking/preference based on expected value
what is the equation if A is preferred to B
U(A) > U(B)
what is matching law
Choice paradigm with concurrent schedules of positive reinforcement; Distribution of behavior/time responding is measure of choice
what is under matching
failure to match (receive maximum available reward)
what is bias
preference for large and immediate reward
what is the history of optimal foraging theory
Mathematical models of foraging decision; MacArthur and Pianka (1966) patchy food distribution
what are the basic models of optimal foraging theory
diet choice model; patch choice model; risk sensitivity model; stochastic dynamic programming; rules of thumb models
what are deductive research tools used to explore the consequences of working under a given set of assumptions
foraging models
which model is the crow and whelk associated with
foraging model
what are the elements of a foraging model
decision assumption; currency assumption; constraints
what is the decision assumption in the foraging model
which of the forager’s problems are to be analyzed
what is the currency assumption in the foraging model
how are the various choices to be evaluated
what are the constraints in the foraging model
what limits the animal’s feasible choices and what limits the pay-off that may be obtained
what are extrinsic constraints
environmental conditions (seasons)
what are intrinsic constraints
how the animal lives
what is a sequential sampling constraint
typically encounter diet or patch items one at a time
what is knowledge of environment constraint
complete and accurate knowledge of food types, abundance and location
what are the steps in building an optimal diet model
explicit alternatives involving sequential encounters of prey items; compare fitness of the two alternative actions; specify assumptions and constraints under which animals make decisions
what are the characteristics of a patch
encounter rate (rich v poor patch); patch residency; gain function
what is patch residency
decision variable of time spent searching for food in patch
what is patch gain function
net energy “gain”, negatively accelerated function of patch depletion
what are the steps in building an optimal patch residency model
explicit alternatives involving patch exploitation; currency of fitness is same as diet model; specify assumptions and constrains
steps to testing optimal patch residency model
look for optimal residency time when density of patches in habitat changes or when average quality of patches changes; graphical solution
which animal was used to test patch residency time
great tits
when patch density in habitat declines or travel cost increases what should an animal do
forager should remain in patch and deplete them to a great extent
when average patch quality in habitat increases what should a forager do
foragers should spend less time exploiting each patch and deplete them to a lesser extent
how is risk defined
uncertainty of reward (loss and gain)
what is state-dependent foraging
hunger states 1) equal value of items 2) item’s worth decreases as animal becomes satiated 3) item’s worth increase due to high risk of starvation
what is the energy budget rule
forager below its energy budget should be risk prone, otherwise be risk averse; studies of operant analog of risk sensitive foraging compare V1 to F1 schedules of reinforcement
what is Stochastic dynamic programming
uses a common currency of lifetime fitness; foraging decision are state-dependent; capable of modeling trade-offs between competing activities; uses a decision trajectory to model patch choices over a finite time period
descriptive models are decision rules that reflect what
actual decision making mechanisms
what are rule of thumb (ROT) models
simple rules that animals follow to base their choice; research shows that ROT models can approximate optimality
what model is based on architecture of interconnected neurons
descriptive model
What is the cognitive emotional forager model
foraging decision are the balance of emotional states experienced when confronted with foraging decision made under risk of predation
what are the three assumptions with optimal foraging
forager uses knowledge of patch parameters; forager’s decision are based on energy reserves; foragers decision are time-dependent in that it knows the end of the foraging time cycle
what does energy threshold model eliminate
third assumption of optimal foraging
