Do butterflies eat bugs?

No. Butterflies and moths do most of their eating when they are in the caterpillar stage. Almost all caterpillars eat plant parts, but a few are carnivorous. Caterpillars of the carnivorous Harvester butterfly (Feniseca tarquinius) of the eastern U.S. eat woolly aphids. The adult female butterfly lays her eggs in the middle of aphid masses.

Source: Opler & Krizek. 1983. Butterflies east of the Great Plains. Johns Hopkins Univ. Press.