Foraging Flashcards
what are important factors to foraging
Exposure to predators
Where the food is at/where it goes or travels
Where your habitat is
Where they place their “traps” (spiders!)
When the prey will be present
How much energy it takes to get to food
what is the most important goal animals fight to maintain?
animals ALWAYS want to efficiently forage!
2 models to show this: patch model and diet selection model
Patch Model
Predictions about optimal time foraging for food
Expected amount of food to collect in time
Summary: constraints will be present
Prevents optimization
Example: poor weather, competition from others
Summary: animals want to optimize foraging behaviors
No silly goose time, be serious rn plz
Summary: all behaviors have costs and benefits w/foraging
Benefit: getting food
Costs: predation, keeping young safe
Diet Selection Model
types of food expected to eat
Describe an example of the patch model
- European Starling
- can we predict time to travel to and from and collect food item? Yes!
- can either take 1 item back, as much as they can carry; but both have pros and cons
Patch model theorem; marginal value theorem
Gains curve: cure od diminishing returns
5 food items in approx. 12 minutes, optimal
More or less bad for it
If shorter travel time? Food items and search decreases
example of energy expenditure
Honeybee feed on nectar, Crop: storage
Can be studied through Patch model
Advantageous to fill crop with nectar, but most gone when they get back home; used for energy
the farther the bee went, the less nectar they came home with;However, measured nectar took from each place; they took in same amount of nectar at each
When bee made heavier (wings glue to them wtf what), no nectar practically left
Overall, energy expenditure shown here
Constraints significant factors
Describe the aspects of foraging the honeybee example includes
All species want to be efficient foragers
Constraints will vary by species
Constraints will affect foraging behaviors
Energy expenditure is an important constraint, specifically for this species (varies by species)
What equation is important to the Diet Selection Model?
P = E/(H+S)
What does the equation of profitability and diet selection model tell us about prey choice?
If prey #1 more profitable then prey #2, will prefer #1 over #2
Shown here: shore crab
*note: this doesn’t mean certain sizes won’t be chosen ever, some just preferred for profitability over others
What aspects of foraging do crabs keep in mind?
Shore crab summary:
1 – profitable prey will be chosen
2 – if there’s increase in search or handling time (S or H), profitable prey can become less desirable; could change foraging preferences based on profitability
Name 6 factors to influence foraging behaviors
- profitability
- energy expenditure
- constraints
- predictability of receiving food
- variability in timing of receiving food
- predators
Describe the profitability factor that influences foraging behaviors
profitability considers P = E/ (H+S) to draw conclusions about foraging
Describe the energy expenditure factor that influences foraging behaviors
- example: honeybee
- traveling longer distances and facing obstacles along the way increases use of expenditure
Describe the constraints factor that influences foraging behaviors
animals always want to be efficient as possible, but always constraints working against them
Describe the predictability of receiving food factor that influences foraging behavior
Animals forage differently depending on food guarantee (whether positive or negative)
Example: animal given 2 options – either 3 food items per day for certain # of days (fixed), or 30 food items randomly given for certain # of days (variable)
Fixed is risk-aversive
Variable is risk-prone
Choice they go with depends on needs
