Coleottero vs. scarabeo
The Italian words 'coleottero' and 'scarabeo' both refer to beetles, but they have different usages and connotations.
Coleottero
'Coleottero' is the scientific term for beetle in Italian. It is used in formal or academic contexts when discussing beetles as a group of insects.
I coleotteri formano l'ordine più numeroso di insetti.
(Beetles form the largest order of insects.)
Il biologo studia i coleotteri della foresta amazzonica.
(The biologist studies the beetles of the Amazon rainforest.)
Scarabeo
'Scarabeo' is the common term for beetle in Italian. It is used in everyday language and can refer to various types of beetles.
Ho trovato uno scarabeo nel giardino.
(I found a beetle in the garden.)
Lo scarabeo stercorario è famoso per rotolare palline di sterco.
(The dung beetle is famous for rolling balls of dung.)
Summary
While 'coleottero' is the scientific term used in formal contexts, 'scarabeo' is the everyday word for beetle in Italian. 'Coleottero' is more likely to be used by scientists or in educational materials, whereas 'scarabeo' is commonly used in casual conversations about beetles encountered in daily life.