Prey Defense Strategies Against Predators
| Defense Type | Mechanism | Example | NEET relevance |
|---|---|---|---|
| Cryptic coloration | Camouflage — blend with background | Stick insects, leaf-tailed gecko | Frequently cited as example |
| Batesian mimicry | Harmless mimic resembles harmful model | Viceroy butterfly (harmless) mimics Monarch (toxic) | Distinguish from Mullerian |
| Mullerian mimicry | Multiple harmful species share warning signals | Wasps and bees share yellow-black | Honest mimicry — all are dangerous |
| Chemical defense | Toxic/repellent compounds | Calotropis → cardiac glycosides; Poison dart frogs | Calotropis is the NEET example |
| Aposematic coloration | Bright warning colors signal danger | Monarch butterfly (orange-black) | Connected to cardiac glycosides |
| Morphological defense | Spines, shells, horns | Porcupine quills, turtle shells | Less frequently tested |
Ecological Role of Predation
Predators serve critical ecosystem functions:
- Population regulation: Prevent prey from overpopulating and exhausting resources.
- Keystone predation: Removal of dominant competitors allows subordinate species to persist → increases biodiversity.
- Natural selection: Remove weak/sick individuals → improve prey population fitness.
- Trophic cascade: Top predator decline affects all lower trophic levels (e.g., wolf removal → deer increase → overgrazing → plant decline).
Lotka-Volterra Cycle (Canadian Lynx-Snowshoe Hare)
The classic 10-year oscillation cycle:
- Hare increases → Lynx increases (food available)
- Lynx high → Hare declines (heavy predation)
- Hare low → Lynx declines (starvation)
- Lynx low → Hare recovers → cycle repeats
Key: Predator peak LAGS BEHIND prey peak by 1-2 years.