Predatory-prey interactions Flashcards
(5 cards)
What is predator switching?
Predator switching is when a polyphagous predator that partially specialises may change behaviour to focus on a different prey species if relative abundance of prey species changes.
Define and outline the three types of functional response in predators
Functional responses occur when changes in prey density are reflected in predator feeding behaviour; as prey density increases, number of prey per predator increases in different ways.
Type I is characterised by a linear / constant rate of increase until saturation where it plateaus.
Type II is characterised by a more gradual saturation at an increasingly slower rate of increase in number of prey per predator as prey density increases.
Type III is characterised by a sigmoidal rate of increase that approaches a maximum prey per predator, starting from a very low predator response at low prey densities.
Define and explain the numerical response in predators
The numerical response of a predator is the relationship between prey density and predator density. As prey density increases, predator survival increases, offspring production increases and immigration increases.
How might prey avoid being driven to extinction by predators?
Prey refuges allow prey to avoid being driven to extinction by predation. They take various forms, including physical hiding places, differential habitat occupation, certain predator behaviour, prey polymorphism and superpredation.
What is the Lotka-Volterra predator-prey model?
The Lotka-Volterra predator-prey model is a set of coupled equations based on the exponential growth model and adapted to include predator-prey dynamics based on a Type I functional response. For example:
dN/dt = rN - aPN
and
dP/dt = faPN - qP
where N is the number of prey, P is the number of predators, r is the intrinsic birth rate of prey, a is the predation rate on prey, q is the intrinsic mortality rate of predators, and f is the predator efficiency / its numerical response.
