chapter 11: foraging Flashcards
foraging
searching for an consuming food
search image
forming a representation of a prey item so it becomes easier to find over time
optimal foraging theory
a set of mathematical models used to predict various aspects of animal foraging behavior within a given set of constraints
what are the advantages of search image?
helps and animal filter out what is and isn’t prey, response to finding cryptic prey
what are the 3 categories of OFT models we talked about-
- what to eat
- how long
- how does variance impact what is eaten
what does each prey item have?
- energy (e)
- encounter rate (lamda)
- handling time (h)
energy value
e, how much energy it provides the animal eating it
encounter rate
lamda, how often the animal eating it encounters it
handling time
h, how much time it takes for an animal to find, kill and ingest the prey
what is the profitability formula
p= e/h
what does the OFT model predict about which type of prey should be chosen during foraging?
weighs the costs and benefits to predict what an animal should do to maximize its fitness
if given a choice between 2 prey items an one is more profitable than the other, what does the OFT model predict about when to eat the less profitable prey? what variable matters the most?
- NEVER IGNORE the prey 1, if ODM is true then you should ONLY take the most profitable, but if it is false you should take both
- the variable that matters the most is lamda 1 also known as encounter rate of prey 1
what are the main points of the great tit study?
great tit (bird)
- presented with big and large food
- increase intake of small food as encounter rate for big food goes down
what does the OFT model predict about how long an animal should remain in the same food patch that is being depleted over time?
it predicts that
- food depletion
- potential predation during travel
- lost time foraging
what is the Marginal Value Theorem?
a model used to predict how long an animal should remain in the same patch
what are the MVT predictions?
gains of staying in a patch will decrease as a patch is depleted by a forager
know how to read a gain curve
x axis: time
y axix: energy gain or food intake
overall: arrive time where the curve starts on x axis and then as time goes on, the gain increases and then flatens out and plateaus
when should a forager stay in a patch?
they should stay in a patch until they can do better elsewhere
when should a forager leave?
- when the gain curve flattens
- at the point when the line touches the curve is the optimal time to leave
what ways is the MVT used to understand behavior not related to foraging?
- how long should a male look for a female
- how long should a parasite look for a host
what is predicted by the risk- sensitive optimal foraging model?
animal’s hunger state will determine which patch it chooses
why does it make sense to be more risk- adverse in consistent food patches and more risk prone in variable food patches?
consistent food patches provide enough energy to meet requirements, and varialbe food patches if you are starving a variable food patch is your best option
what are some ways foraging behavior can be affected by group size?
Large groups - can spend less time being vigilant and more time foraging
why does increasing gorup size increase the amount of food each forager receives?
the larger the gorup sizw the more eyes there are to watch the group while the others can focus on only foraging
What is public information for animals and how can it be used during foraging?
use the actions of others to provide updated information about the eviornment’s condition
Understand the results from the “planning for the future” study on scrub jays
the jays stored food in the no food compartment rather than the food compartment to save food for later
