Without insects everything in the nature would be as dirty as in the towns! Insects are earth cleaners and earth makers! I live in the forest and if I eat outside of my house and spill some food, it will be gone in a few hours. If animals or birds die, insects transforms them into to dirt, they make compost out of dead plant materials too, so that new plants, berries, vegetables and trees can grow in abundanse, oh my G! All insects that doesn't attac you or invade your house, we should bless!
Ζουζούνι = bug; the word is used in informal contexts the way bug is used informally in English. (There is a formal definition of bugs as a very specific group of insects - these are the "true bugs" in English.)
Έντομο = insect; a clear zoological classification is implied here, but the word can be used in both formal and informal situations.