Baike doesn't gloss the insect line at all, but I separately searched it and apparently it's two kinds of pests that eat seedlings that are a metaphor for harming people or the country. (The second word I think? only means thief, so I had wondered if it was meant to be an actual insect or just an insult for a human)

I don't think they're soldiers, I think the narrator is still insulting the corrupt people in power.