What does the cryptic crossword clue "Turtle said to metamorphose, sound as an insect (10)" mean?

The wordplay uses an anagram. anagram of TURTLE + SAID = STRIDULATE The answer is STRIDULATE.

Turtle said to metamorphose, sound as an insect (10)

Times Cryptic #28593 | 24 Across | 2023-05-03 flower