Jumping insect (4)
I believe the answer is:
flea
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">jumping insect</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for flea that I've seen before include "Small parasitic insect" , "Jumping parasite" , "Little jumper?" , "source of infestation" , "Bloodsucking parasite" .)