Ch. 13 Predation and other exploitative interactions

Types of interactions

Grazers, parasites, parasitoids, predators

Grazing

Low intimacy, low lethality, high levels of grazing reduces population viability, ex. deer

Parasitism

high intimacy, low lethality, living in / on a host

micro parasites

small, generally intracellular

macroparasites

large, extracellular

endoparasites

live inside host

ectoparasites

live on the surface of the host

Hemiparasite

plant capable of both parasitizing other plants and undergoing photosynthesis

Parasitoids

high intimacy, high lethality, laying eggs inside a host, hatching eating and emerging from the host killing it

predation

low intimacy, high lethality, we know this one

counter defenses

constitutive defenses, and induced defenses

constitutive defenses

defensive traits that are expressed continuously

induced defenses

defensive responses expressed following injury or threat

coevolution

a process in which interactions between species lead to reciprocal adaptation

Prey isocline

Hosts increase when predator population is low and vise versa

Predator isocline

predators increase when prey population is high and vise versa

Predator-prey isoclines together

time lag in predator population

Non-consumptive effects

Changes in the behavior, growth, development, or reproduction of prey/hosts in response to the presence of predators, parasites

Predator responce to prey density type I

Number of prey consumed increases linearly with prey density

Predator responce to prey density type II

consumption of prey decreases as prey density approaches asymptote (Appetite satiation or handling time)

Predator responce to prey density type III

low consumption at low prey density, then non, linear increase (Need to develop effective search image, prey switching at low prey density, at higher density, fewer open refugee for prey)