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
Describe variability in timing of receiving food factor that influences foraging behavior
Specific time: they learn/know time
Random time: unexpected
Example: mouse in skinner box
Animal will often risk it, since future like is not a guarantee for them
Describe predators as a factor that influences foraging behaviors
animal extremely hungry and will take on mor risks
areas chosen for forage affected by prescence
Describe the experiment of the Yellow Eyed Junco
Birds placed in 1 of 2 conditions
Condition A: chilly @ 34 degrees F
Condition B: 67 degrees F
Both given fixed option of 3 seeds or variable option of 0-6 seeds
Tested option they preferred
Cooler chose variable option while warmer chose fixed options
Cooler need more than 3 seeds, risking for more food/energy
Warmer do not have higher metabolic need, won’t need as much food
Note birds also need to be aerodynamic, not too heavy in weight
Describe the Skinner Box Experiment
Rat given cue to either switch lever/get reward (positive reinforcement) or a shock if not pressing lever
Will rats prefer food given at fixed time @ 15seconds or food given at shorter or longer unexpected time?
Animals gamble (unhealthy much lol?) since life is not guarantee; always prey for something most of the time!
Describe the Kingfisher experiment
Shows case of vigilance
Stickleback in high density area of water fleas
Its so distracted by waterfleas that they do not notice kingfisher predator present
Will put them in areas where less distracted by water fleas
Describe foraging behaviors of Kent State Black Squirrels
Note:
When squirrels find food and eat, head is up
Head up to be able to look around
Animals with eyes on side do less of this
Why is the Patch Model often an over-estimation of an animal’s foraging behaviors?
Based on the Patch Model, how does the search time and predicted number of food items change as travel time increases or decreases?
What were the main results and conclusions of the experiment involving stickleback fish?
What factor(s) can increase or decrease the profitability of prey?
What does a Gains curve represent?
Under what conditions might an animal engage in more risky behaviors when foraging?
What assumptions are typically made when utilizing the Patch Model?
What does the Diet Selection Model tell us about the choices that animals make when foraging?
How does future discounting affect an animal’s foraging behaviors?
