Predation and Herbivory

Introduced Species

Introduced to a region of the world where it has not historically existed

Invasive Species

Species that spread rapidly and has negative effects on other species, human recreation, and human economics

Mesopredators

small carnivores that consume herbivores

Top predators

predators that typically consume both herbivores and mesopredators

Biological control

introductions of one species to help control the abundance of another species

Parasitol

live in and consume host tissue until the host dies

Do biological controls always work?

they do not always work

coexistence can occur if

prey have refugia from predators, prey have dispersal ability, predator reproduction is slightly delayed

Lotka-Volterra model

model of predators-prey interactions that incorporates oscillations in the abundance of predators and prey population

Equilibrium isocline

populations size of one species that causes the population of another species to be stable

Joint population trajectory

simultaneous trajectory of predator and prey populations

Joint equilibrium point

point at which the equilibrium isoclines for predator and prey populations cross

Functional response

relationship between the density of prey and an individual predator’s rate of food consumption

Type I

predators rate of prey consumption increases in a linear fashion with an increase in prey density until saturation occurs.

Type II

predators rate of prey consumption begins to slow down as prey density increases and then plateaus when saturation occurs

Type III

functional response in which a predator exhibits slow prey consumption under low prey densities, rapid consumption under moderate prey densities and slowing prey consumptions under high prey densities

Numerical response

change in the number of predators through population growth or population movement due to immigration or emigration

behavioral defense

alarm avoidance, activity reduction, increase reproduction

Crypsis

camouflage that either allows an organism to match its environment or break up the cutline of an individual to blend in better with environment

Structural defense

reduce predators’ ability to capture, handle, or attack prey

Chemical defense

ability to repoduce toxin or chemical to reduce palability

Batesian mimicry

palatable species evolve warning coloration that resembles unpatable species

Mullerian Mimicry

several unpalatable species evolve a similar pattern of warning color

Defenses are costly

high in energy cost, reduce time feeding, reduced time mating

coevolution

two or more species affect each other’s evolution