grubs in fruit
螬 refers specifically to grubs or larvae that infest and feed inside fruit, causing damage from within.
螬 combines 虫 (insect) with 曹, which likely provides the sound. The character is used for fruit-infesting grubs, but the exact historical development is uncertain.
An insect 虫 inside a fruit, represented by the 曹 component (which resembles a container), is a grub eating from within.
For ソウ, imagine a grub inside a fruit making a soft 'sow' sound as it burrows: sow -> ソウ, and the insect is hidden inside.
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