Checks for parasites (5)
I believe the answer is:
ticks
This might be a double definition.
'checks' is the first definition.
The definition and answer can be both to do with perception as well as being verbs in their -s form.
Maybe you can see an association between them that I can't see?
'parasites' is the second definition.
(I've seen this before)
'for' acts as a link.
Can you help me to learn more?
(Other definitions for ticks that I've seen before include "They suck from warm-blooded animals" , "Parasites" , "Parasitic arachnids" , "Signs of approval" , "Bloodsuckers; seconds" .)