kind of ant, may fly
蜉 centers on a small, short-lived insect: a kind of ant or a mayfly. The two given meanings both point to tiny, ephemeral creatures.
蜉 combines the insect radical 虫 with the phonetic component 孚, which likely indicates the sound. The exact historical development of the character is uncertain, but it is used for small insects like mayflies and certain ants.
The insect radical 虫 on the left hints at a bug, and the right side 孚 looks a bit like a tiny creature with legs. Picture a mayfly or ant scurrying around.
For フ, imagine a mayfly buzzing around your food: the sound 'foo' like a quick buzz, and you shoo it away. 'Foo' cues フ.
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