Many species of benthos are able to move around and expand their distribution by drifting with currents to a new location during the aquatic phase of their life or by flying to a new stream during their terrestrial phase. Most benthic species can be found throughout the year, but the largest numbers are seen in the spring and summer during their reproductive periods. In colder months, many species burrow deep within the mud or remain inactive on rock surfaces. Many aquatic insects undergo metamorphosis - the transition from egg to larva to pupa and finally to adult. After becoming adults, the majority of insects live for only a brief time, usually a few hours to a few days, while they locate mates and reproduce.
Benthic organisms are an important part of the food chain, especially for fish.
Many feed on algae and bacteria which are on the lower end of the food chain. Some shred and eat leaves and other organic matter that enters the water. As benthos die, they decay, leaving behind nutrients that are reused by aquatic plants and other animals in the food chain. Unlike fish, benthos can not move around as much, so they are less able to escape the effects of sediment and other pollutants that diminish water quality. Therefore, benthos are reliable indicators of stream and lake water quality.