Aphids are small, soft-bodied insects belonging to the family Aphididae. They typically measure 1 to 10 millimeters in length and come in various colors, including green, black, and yellow. Aphids feed on plant sap, which can weaken plants and lead to stunted growth. They are often found in clusters on the undersides of leaves and can reproduce rapidly, sometimes giving birth to live young. These insects are known for their role in agriculture, as they can transmit plant viruses. Additionally, they produce a sticky substance called honeydew, which can attract other pests like ants and lead to the growth of sooty mold on plants.