Prior anticipation, rather than after-splat cleaning, would be preferred. A really good quality wax job; Rejex, Ice, Zaino, Ultimate, etc., well in advance of bug season, really makes removing the little splattered buggers easier. Same with Rain-X on the windshields. After these applications a good hosing off will remove most bug parts.
Here we're plagued several times a year with "love bugs" - and they'll eat right thru the clearcoat in a day if left on the finish. Sometimes they're so bad that a short high-speed drive will coat the front of your car~! Euuuuw!