You're sexually attracted to insects. When you see a butterflyflying, you pop a boner. Symptons may be, unable to look at insects without feeling turned on, heavy breathing in close promixity of a insect, searching insect porn, masturbating to insects, and strange addiction to insects.
Dude: Look at that ant.. broI think I'm getting a boner..
Dude2: I think you have insectophilia.