Why might bloodworms be able to live in polluted water with not much oxygen while mayfly nymphs cannot survive?

Bloodworms, the larvae of midge flies, possess a unique adaptation that allows them to thrive in low-oxygen environments. They can tolerate high levels of pollution and have a hemoglobin-rich blood that efficiently binds and transports oxygen, enabling them to survive where oxygen levels are depleted. In contrast, mayfly nymphs are more sensitive to water quality and oxygen levels, making them less capable of enduring polluted conditions. Their physiological requirements for clean, oxygen-rich water limit their survival in such environments.