| Interaction | Notation | Species A | Species B | Example | Key Distinguisher |
|---|---|---|---|---|---|
| Mutualism | +/+ | Benefits | Benefits | Rhizobium-legume, lichen, mycorrhiza | BOTH gain |
| Competition | -/- | Harmed | Harmed | Paramecium (Gause's experiment) | BOTH lose |
| Predation | +/- | Benefits (predator) | Harmed (prey killed) | Lion-deer, snake-frog | Predator KILLS prey |
| Parasitism | +/- | Benefits (parasite) | Harmed (host survives) | Plasmodium-human, cuckoo-crow | Parasite EXPLOITS without killing immediately |
| Commensalism | +/0 | Benefits | Unaffected | Orchid-mango tree, barnacle-whale, cattle egret-cattle | One gains, one truly neutral |
| Amensalism | -/0 | Unaffected | Harmed | Penicillium-Staphylococcus | One harmed, one truly neutral |
Mimicry Sub-types (under Predation — prey defense):
| Mimicry Type | Mimic | Model | Example | Honest? |
|---|---|---|---|---|
| Batesian | Palatable (harmless) | Unpalatable (toxic) | Viceroy mimics Monarch | Dishonest (mimic is harmless) |
| Mullerian | Unpalatable (toxic) | Unpalatable (toxic) | Wasp + bee share yellow-black | Honest (both genuinely dangerous) |
Mnemonic for 6 interactions: "My Car Parked Past Commuting Arteries" (Mutualism, Competition, Predation, Parasitism, Commensalism, Amensalism)