Resource acquisition by societies part 1 Flashcards
what do animals need to balance when deciding when and where to forage for food?
- time
- reward
- risk
what does optimal foraging seek to explain?
it seeks to explain the diversity of approaches to foraging based on the costs and benefits of alternative strategies available to an organism
define Central place foraging
a mode of foraging where the forager must return to a central location to process, consume, store and/or share food resource
what benefit/cost do greater foraging distances provide?
- benefit of more food and a greater variety of food types
- cost of time, energy expenditure, and risk
What kind of decisions do foragers have to balance?
- How long to look?
- How hard to work?
- Once food is located, how much should be retrieved?
- How quickly should it be retrieved?
Central-place foraging is the foraging mode for what kinds of organisms
any shelter-building social organism, and many others with a well-defined core area
Having a shelter and central-place foraging may allow what?
it may allow new food types
Having a shelter and central-place foraging may allow new food types - Many group members may what?
further facilitate access to new food types
Having a shelter and central-place foraging may allow new food types - tradeoffs of having many group members
a subset of all society members must feed the whole society
Having a shelter and central-place foraging may allow new food types - what is the cost for the tradeoff
- cost is that individual foragers must forage longer and further from the central location than a solitary organism would
- time, distance, and risk costs are amplified
Central-place social foraging - Example
leaf-cutting ants
central-place foraging - leaf-cutting ants
A leaf-cutting ant forager may travel several hundred meters to a foraging site
central-place foraging - costs
- Time and energy spent foraging
- Increased forager mortality rates
central-place foraging - which social traits offset the costs?
- Division of labor
- Foraging specialization tied to increase in age and/or a decline in fecundity
what do individual strategies in social foraging do
Balances the costs and benefits of foraging at the level of individuals
individual strategies
- Search behavior.
- Orientation mechanisms.
- Load size.
- Morphological adaptations.
search behavior - define Correlated random walk
Each subsequent step is in a random direction, but with a degree of correlation to the previous direction of movement.
correlated random walk - Optimal turning angle (tortuosity) depends on what?
the probable distribution of food sources and the number of cooperative searchers
correlated random walk - Encounters with other group members or lack of food favors what?
favors straighter search paths and greater distances
correlated random walk - how do single foragers perform optimally
they use a tortuous search path to maximize area coverage around the “central place”.