Predation Flashcards
True predation
consumption of all or part of an organism
prey is alive when first attacked
types of predator (diet)
carnivores
herbivores
omnivores
types of predator
true predators
grazers
parasites
parasitoids
3 key important factors with predators and prey
probability of being encountered
probability of being attacked
probability of being consumed
What attributes of predators and prey influence the probability of being encountered?
activity patterns, refuges, crypsis
What attributes of predators and prey influence the probability of being attacked?
level of hunger, prey mobility, prey size, behaviour
What attributes of predators and prey influence the probability of being consumed?
prey size, prey escape behaviour, prey defences
energy gained during feeding period =
fx Time searching + Time handling
Optimal foraging theory
foragers should prefer most profitable prey
Forager +food availability
an efficient forager should broaden its diet to include low value prey when high value prey decrease in abundance
Monophagous
one prey type (parasitoids and parasites)
specialists
Oligophagous
few prey types (parasites and true predators)
specialists
Polyphagous
many prey types (grazers and true predators)
specialists
When handling times are short, relative to search time, it makes sense to be a…
generalist (e.g. insectivorous birds)
When handling times are long, relative to search time, it makes sense to be a…
specialist (e.g. lions)
Generalists will…
pursue a large proportion of what they encounter, regardless of profitability of prey
Specialists will…
keep searching until find preferred (most profitable)
Type 1 predation
Feeding rate = aN
Attack rate = a
Prey density = n
Type 2 predation
Feeding rate = aN/ (1+ahN)
Handling time = h
Type 3 predation
Feeding rate = CN2/d2+N2
Max feeding rate c = h-1
Half saturation constant d = (ah) - 1
Change in prey population
Lotka-Volterra
dN/dt = rN - aPN a = attack rate P = number of predators N = number of prey r = constant, pop. growth rate
Change in predator population
Lotka-Volterra
dP/dt = faPN -qP q = mortality rate P = number of predators N = number of prey f = predator's efficiency at turning food into offspring a = attack rate
