Earthworms are not true insects – they are Annelids, related to leeches. They consume decaying organic matter in soil and assist with nutrient cycling and soil structure. Their burrowing activity helps introduce oxygen and aerate the soil, improving its structure.
When soil is heavily compacted, worms are driven close to the surface. Their galleries can actually bubble the soil upwards, creating ridges and uneven patches and disfiguring the lawn. The best solution to this problem is regular aeration to relieve soil compaction. Once oxygen is introduced lower down in the soil, the worms will migrate back down where they belong.