While there are hundreds of species of earthworms, anyone who makes compost knows the redworm, or Eisenia fetida. They make what's considered perhaps the richest form of natural fertilizer — a true friend to farmers and gardeners alike.
What you might not know is that very low levels of pesticides can kill these "black gold" producers. If they don't kill outright, pesticides can cause other serious harm, like reducing worms' ability to reproduce. Exposure to the neonicitinoid pesticide imidacloprid — well-known for its toxicity to honeybees — can also cause serious harm to worms, damaging DNA and deforming sperm. Bad news.