Defenses of prey species to lessen impact of predation :
→ Camouflage (cryptic colouration) of some insects & frogs.
→ Some are poisonous and so avoided by the predators.
→ Monarch butterfly is highly distasteful to its predator bird. It is due to a special chemical in
its body.
→ It is acquired during its caterpillar stage by feeding on a poisonous weed.
→ Thorns (Acacia, Cactus etc.) are the most common morphological means of defense of plants.
→ Many plants produce chemicals that make the herbivore sick, inhibit feeding or digestion, disrupt its reproduction or kill it. E.g. Calotropis produce highly poisonous cardiac glycosides.
→ Therefore cattle or goats do not eat it.
→ Nicotine, caffeine, quinine, strychnine, opium, etc. are defenses against grazers and browsers.