The term 'little bug' can be described by two crossword solutions: MITE and GNAT. Mites are tiny arachnids, related to spiders, that live in soil, on plants, and in water. They are usually less than 1 millimeter in size. Gnats are small flies that are typically found near water sources, such as ponds, streams, and lakes. They are usually less than 5 millimeters in size. Both mites and gnats are considered pests, as they can cause damage to crops and spread disease.