Detective or insect? (3)

I believe the answer is:

dor

I'm a little stuck... Click here to teach me more about this clue!

'insect?' is the definition.
(I've seen this in another clue)

'detective or' is the wordplay.
'detective' becomes 'd' (this could be a standard abbreviation of which I'm unaware).
'd'+'or'='DOR'

Can you help me to learn more?

(Other definitions for dor that I've seen before include "Creature" , "Dung-beetle" , "European dung - beetle" .)

I've seen this clue in the Sydney Morning Herald.

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