L5&6 - foraging Flashcards
(15 cards)
what is the premise of optimality models used to predict foraging behaviours
behaviour is shaped by natural selection, considfer costs and benefits and find the maximum net gain, for example games theory - what strategy is favoured depending on what others are doing
what is the Darwinian fitness ideal
number of grandchildren rather than children because it includes reproductive success of offspring
what is currency in optimality models
surrogate of fitness, eg maximum rate of energy intake or number of offspring
what are two types of foraging models
solitary and social foragers
what are the 2 options of acquiring optimal diet
be a generalist or specialist, specialist only attack most profitable prey
under what circumstances will a species become a generalist
if there is no reason to pay attention to the other prey items, therefore encounter rate λ of the most rpofitable prey determines whether the less profitable items are taken
what does optimal residence time in a patch hypothetically depend on?
patch quality and average trable time between patchesm time in patch asymptotic to energy gained (resources in patch get depleted)
what is the marginal value theorem
further travel means individual will stay longer in first patch
what is central place foraging
that animals will prioritize foraging patches closer to the central location, as the time and energy spent traveling to and from the patch are considered in the net energy gain. , best fit family gain model
how can inclduing risk sensitivity help create more accurate models
in upredictable environments, foragers may responde to bariance in reward to the risk of variable food patch rather than the mean, eg yellow eyed juncos - would take the risk (all or nothing) even if mean of resource is the same as another patch when starved
how can including nutritional constrains help create foraging models
eg herbivores contrained by requirement for minerals and size of rumen - find optimal plant intake that also satisfies nutritional needs, also example of predatory beetles where a lipid to protein ideal ratio needed for egg production
how can th risk of predation influence foraging
antipredatory behaviour inlfuences where an animal will forage, eg reintroduction of wolves in yellowstone lead to elk population decreasing due to picking safer less lush areas and had lower offspring due to lower calorie intake
what are some factors that might influence behaviour when foraging in groups
amount of food in a patch depleted faster when shared with others, leads to scramble competition, dictates what strategy is going to be chosen for patch selection given distribution of other foragers
what is the Ideal free distribution prediction to choosing a patch in a group
foragers distribute themselves across patches proportionally to the patches quality thus all get equal pay off
what is social exploitation of others and how do we model it
either scrounger or producer, frequency of both strategies is dependent on each other, meets at a stable equilibrium frequency (SEF) where there is equal fitness of both strategies, not rigid
