Predation & Herbivory

Competition

Interaction where two or more species compete for a resource that is in short supply (-/-)

Predation

Interaction where one species, the predator, kills and eats the other, the prey (+/-)

Herbivory

Interaction where an herbivore eats part of a plant or alga (+/-)

Parasitism

Symbiosis where a parasite derives nourishment from a host, which is harmed (+/-)

Mutualism

Interaction where both species benefit (+/+)

Commensalism

Interaction where one species benefits while the other is unaffected (+/0)

Facilitation

Interaction where a species has positive effects on other species without intimate contact (+/+ or 0/+)

Biological Control

Using natural enemies to control pests (e.g., introducing beetles to eat Hemlock Woolly Adelgids)

Red Queen Hypothesis

The theory that the driving force behind evolution is the fight for survival against co-evolving predators/competitors, not just the environment

Parasitoids

Predators (like wasps or fungi) that eventually kill their host and can alter host behavior

Structural defenses

Plant defenses involving physical barriers like thorns and silica

Secondary compounds

Chemical plant defenses such as tannins (indigestible) or caffeine/nicotine (toxic)

Müllerian mimicry

Mimicry where two toxic species look alike to mutually reinforce their warning signals

Batesian mimicry

Mimicry where one non-toxic species mimics a toxic species

Aposematism

Warning signals and coloration that warn predators of toxicity

Crypsis

Camouflage that allows an animal to avoid detection (e.g., walking stick insect)

Predator satiation

A defense strategy of producing mass numbers of offspring/seeds at once to overwhelm predators (e.g., masting or periodical cicadas