Ecology
Lecture 8 Predation 2 10/03/21
How do predators respond to prey populations?
- Numerical response- change in the population in response to the density of prey. Consists of
reproduction and aggregation.
- Functional response- relationship between rate of consumption by a predator and the
density of the prey – types I, II, III.
Holling’s functional responses of predators to prey density
Functional responses
- Type I – linear – the more food the more is eaten (no processing or searching time).
- Type II – decelerating – there is processing time (handling, eating) leading to a maximum
intake rate.
- Type III – accelerating up to a maximum – possibly due to a learning or switching to the most
abundant prey.
Some experimental insight into functional responses
- Peromyscus maniculatus (deer mouse).
- From Real (1979) Ecological determinants of functional
response Ecology 60: 481-485
- Experiments on caged animals offered pine sawfly cocoons at
different densities with either sunflower seeds or dog
biscuits.
- Caged animals offered seeds in different spatial distributions.
Alternative food available at all times.
Lecture 8 Predation 2 10/03/21
How do predators respond to prey populations?
- Numerical response- change in the population in response to the density of prey. Consists of
reproduction and aggregation.
- Functional response- relationship between rate of consumption by a predator and the
density of the prey – types I, II, III.
Holling’s functional responses of predators to prey density
Functional responses
- Type I – linear – the more food the more is eaten (no processing or searching time).
- Type II – decelerating – there is processing time (handling, eating) leading to a maximum
intake rate.
- Type III – accelerating up to a maximum – possibly due to a learning or switching to the most
abundant prey.
Some experimental insight into functional responses
- Peromyscus maniculatus (deer mouse).
- From Real (1979) Ecological determinants of functional
response Ecology 60: 481-485
- Experiments on caged animals offered pine sawfly cocoons at
different densities with either sunflower seeds or dog
biscuits.
- Caged animals offered seeds in different spatial distributions.
Alternative food available at all times.
