6+7 Flashcards
Currency
Surrogate of fitness
Assumptions
Animal and mats and affects relationship between classes strategy and currency
Currency for most
Long term maximisation of energy intake -calories
Optimal diet / prey model
Strategy
Predictions (4)
Attack or eat or ignore and search?
Should either specialise or generalise (no partial preferences)
Low s1 specialist and vice versa
Decision to specialise depends on s1
All or nothing - switch should be suddenly
Optimal diet / prey assumptions maths 3
Constant mean prey encounter rate
Random sequential prey order
Liner relationship between rate of energy and fitness
Optimal diet / prey model strategy assumptions animal
Instant recognition of prey
Info about prey abundance and profitability
Sequential prey encounters
Mutually exclusive search and handle time
Profitability
E/ h
Profitability when adding in search time
E/ S + h
E h and s mean
Energy value
Handling time
Search time
Optimal patch / marginal value theorem
Strat
Predictions 2
Continue to exploit patch or abandon and look for another?
Patch optimal residence time depends on t - travel between patches If f(t) and t are known can predict t* fromMVT
Note you can use average patch qual if quality varies
If travel time long should spend less time in patch and take what you can and leave before you lose energy
Maths assumptions of optimal patch 4
Fixed prey density at starts and decreases exponentially
Deacceleration of rate of energy intake
Travel time function of distance between them only
Equal energy costs of travel time and and search time
What spp for optimal prey test
Paris major and mealworms
Blue gill sunfish and daphnia
Why partial preference in optimal diet
Identification problems
Experience / development
Factors influencing behaviour ie predator avoidance
Optimal patch assumptions animal 4
Instantly recognise patchees
Info ie patch quality known
Travel tie between patches known
Random distribution of prey within a patch
Spp for patch marginal value
Blue tit
Moose
Moose info
Lake shore fo sodium
Michigan Canada
3 constraunts for linéarité modèle
Sodium rumen size and energy
Why assumptions broken for patch
Knowledge some may need longer to assess patch qual
Variation in rewards -can lead to risk sensitive foraging
Predator avoidance
Nutritional constraints result in trade off with energy max
Risk of predation
3 spines stickelback
Daphnia 2,20,40
If predator present feed at low density
Risk sensitive foraging info
For unpredictable enviro
YELLOW EYED JUNCO
Positive energy diet - risk averse 3
Negative energy diet - risk prone 6 or 0
Positive energy diet and negative of yellow eyed junco
Positive - starved 1 he only 19 degrees
Neg - starved 3 hrs 1 degree
Social exploitation
Tactic is to be scrounged or produced Spice finches Stable equilibrium freq = 3 Producer always same fitness Scrounger fitness negative frequency dependence
Social exploitation and spice finches
Barnard and sibly
1981
Barnard and sibly when
1981
Fret well and Lucus when
1972
Ideal free distribution
Strategy
Predictions 2
Which food patch to choose given the distribution of other group members
Fm foragers distribute proportional to patch quality andresourcematching rule means you get equal pay off
For both patches as you increase number of competitors you decrease the rewards
Ifd example spp
Milinskis stickleback and daphnia
1:5 and shifted
IFD animal assumptions 3
Animal know quality of ALL patches so can choose best one
Can equally travel to all patches “free”
Payoff varies between patches not predators
IFD Maths assumptions
Different starting densities on patches
Prey density decreases consistently
No cost to predator travel between patches
Strategy
Specified behaviour options with different pay off
