Moths flying into the flame is an instinctive behavior.
Tips
usage
蛾 is a bound morpheme — in everyday speech you almost always hear 蛾子 (ézi) or 飞蛾 (fēi'é, 'flying moth'). The classic chengyu 飞蛾扑火 (fēi'é pū huǒ, 'a moth flying into the flame') describes someone rushing toward their own destruction.
memory
Compare 蛾 (moth) with 蝶 (butterfly, dié). Both have the 虫 (insect) radical, but 蛾 hides 我 (wǒ, 'I') and 蝶 hides 枼 — moths often have plain wings and dull colors, while butterflies (蝶) carry the 'leaf' element evoking colored wings.
Insect radical on the left, the indexing radical. 虫 originally depicted a coiled snake but in compounds names anything small and many-legged. 蛾 is the moth — a nocturnal cousin of the butterfly. The radical groups it with 蝴 butterfly, 蜂 bee, 蚊 mosquito, 蚂 ant.
Right side 我 supplies the sound — wǒ shifting to é, an old reading that survives only in this and a handful of related chars. Pure phonetic role; the I-pronoun meaning has no semantic role. Same phonetic also drives 鹅 goose, 俄 sudden, 饿 hungry.
