Industrious insects (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">industrious insects</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for ants that I've seen before include "24 [INSECT] s" , "They live in a formicary" , "Hard workers" , "Inhabitants of a formicary" , "Soldiers" .)