פירוש על עבודה זרה 52:5

One probably does not eat a flea or a gnat because one is hungry. Not much nourishment there. One eats a small bug does so only to provoke—because it is forbidden. This seems to prove that even one who sins in order to provoke is still an apostate and not a heretic. The Talmud rejects this and suggests that the person may have eaten the bug neither to provoke nor to feed his hunger. He may have just been curious as to what a forbidden thing tastes like.