They're invented words - this is an interview with a sci-fi writer, remember! :)
English natives wouldn't know these words out of context, but we'd get an idea from what we recognise: "arakzid" sounds a lot like "arachnid" (so, something like a spider? Just a guess) and we'd recognise "crawl" in "crawlzacs".
So, at the very least, we get an impression or feeling from these made-up words.