By Tom DeRosa, Executive Director of CSI. Why do spiders exist? The little, tiny creatures that entomologists study and master are filled with so many surprises that make us ponder. They possess amazing features that can't be matched. These include their ability to defy gravity with their wings, their rapid population growth, and their complete body transformations from larva to pupa and then to adult. Insects make up over 75 to 80% of all species in the animal kingdom. It's estimated that right now,