Bloodsuckers stop at nothing to infiltrate Stirling (9)
I believe the answer is:
mosquitos
'bloodsuckers' is the definition.
(I've seen this before)
'stop at nothing to infiltrate stirling' is the wordplay.
I cannot quite understand how this works, but
'stop' could be 'quit' (synonyms) and 'quit' is found within the answer.
'nothing' could be 'o' (looks like zero - 0) and 'o' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mosquitos that I've seen before include "Bloodsuckers" , "American natives" .)