Insect stalked periodically by another (6)
I believe the answer is:
beetle
'another' is the definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I can't see?
'insect stalked periodically by' is the wordplay.
'insect' becomes 'bee' (bee is a type of insect).
'periodically' means one should take alternating letters (letters must be selected 'every so often').
'by' is a charade indicator (letters next to each other).
The alternating letters of 'stalked' are 'tle'.
'bee'+'tle'='BEETLE'
Can you help me to learn more?
(Other definitions for beetle that I've seen before include "bug" , "drawing game > has to hurry" , "Heavy wooden mallet for an insect" , "crusher" , "8's (very small) friend" .)