Predation

Herbivore’s specificity can make them an efficient tool in controlling plant populations

Ex. Cactus moth eating cacti in Australia, wiped it out

Ex. Klamath Weed brough under control by introducing beetles that eat it

• Introduced to Europe

• Toxic to livestock & killing it

Virus as control example

Increase of rabbits in Australia

• used to myxoma virus to control them

  • Each time myxoma was introduced it was less effective until the rabbits were immune

Predator-prey cycles

Huffaker modeled predator-prey cycles in the lab

• cycling of predator & prey with a slight delay

• Predator & prey mites with rubber balls and oranges

Lotka-Volterra Model

detlaN/t= rN-cNP

P= # predators

N= # prey

r= intrinsic growth rate

c= capture probability (predator efficiency)

Number of predators supported by a stable environment

P=r/c

Number of prey that causes a stable predator environment

N=m/ac

m=predator mortality

a= efficiency at converting prey into predator offspring

Lotka- Volterra Model

creates isocline (stable population size)

Combing both demonstrates how each affects population size

Anti-predator adaptation of tadpoles

In the presence of predators, tadpoles decrease their activity

Criptic coloration

Blend into the environment

Batesian mimicary

Advertise a false message (something your not)

Ex. wasp, moth, fly

Mullerian mimicary

Advertises the same message in different forms

Ex. Black and bright colors in frogs

• convergence of message