P1: Functional responses of predators to prey Flashcards
How do predators respond to an increase in their food supply?
By eating more - functional response
By reproducing more- numerical response
What do predators do when they have numerical response?
Predator density increases with the increasing prey density. They do this through reproduction and aggregation of predators.
What do predators do when they have functional response?
Predators consume more prey as the prey density increases.
(Type III functional response)
In functional response, as prey numbers increase predators eat more prey. How does the nature of this relationship vary?
It varies depending on the predator and prey species involved, modes of feeding, prey dispersal etc.
What information will functional response curves provide?
Functional response curves provide a theoretical prediction of how predator consumption rates respond to changes in prey density.
What are predators with Type I response called?
Passive predators
- Filter feeders
- Spiders
Explain Type I response?
As prey density increase, the no. of prey consumed by the predator increases linearly until it reaches a plateau or satiation point.
The proportion of prey consumed is constant until the satiation point, then declines.
Rare in nature.
Occurs when handling time is minimal.
What kind of predators have Type II response?
Typical of specialist predators.
More commonly found in nature.
Explain Type II response.
The predators consumption of prey increase at a decelerating rate as the prey density increases.
The response curve rises to an asymptote.
What’s an asymptote?
The maximum number of prey a predator can eat per unit time.
What are predators with Type II response limited to?
The consumer is limited by its capacity to process food.
Handling time rather than prey availability limits the number of prey items a predator can consume.
In Type I response, what is meant by the proportion remains constant up until the satiation point and then declines?
If the prey density doubles, the number each predator eats per day doubles.
Which type of functional response can have increased prey mortality with increasing prey density?
Type III
What is functional response?
The number of prey successfully attacked per predator as a function of prey density. (Solomon, 1949)
It describes the way a predator responds to the changing density of its prey.
Type III is…
When the number of prey density is low, the rate at which prey are consumed slowly increases. After a critical point the consumption increases more rapidly.
