Aphids - GCSE Biology Definition

Aphids are small, soft-bodied insects that are common plant pests. They are usually green or black and feed on the sap of plants using specialised mouthparts. This feeding can weaken plants, reduce growth, and transmit plant viruses, causing damage in agriculture. Aphids reproduce quickly and often form large colonies on the undersides of leaves. They can have a mutualistic relationship with ants, which protect them in exchange for a sugary substance called honeydew that aphids excrete. In GCSE Biology, aphids are an example of pest control methods and plant-insect interactions.