How are larvae of midge insects relevant in environmental assessments?

The relevance of midge insect larvae in environmental assessments primarily lies in their ability to signal the presence of pollutants in water bodies. These larvae are sensitive to changes in their aquatic environment, particularly to the levels of organic pollutants, nutrients, and the overall quality of water. When there is a high concentration of pollutants, the composition and abundance of midge populations may change, indicating a degradation of water quality. Therefore, monitoring midge larvae can provide important information on the health of aquatic ecosystems and help assess the impact of pollution.

While other options touch on aspects related to environmental health, they do not capture the specific role that midge larvae play in directly indicating pollution levels within water systems. The presence of midge larvae alone does not confirm clean water, nor do they solely serve as broad indicators of biodiversity or specifically affect bird populations in a way that directly communicates environmental quality.