Complex sentence: Caffeine in plants acts as a natural pesticide: it can paralyze and kill predator insects feeding on the plant: high caffeine levels are found in coffee seedlings when they are developing foliage and lack mechanical protection.
Split into simpler sentences: Caffeine in plants acts as a natural pesticide: it can paralyze and kill predator insects feeding on the plant. High caffeine levels are found in coffee seedlings when they are developing foliage and lack mechanical protection.