Crane flies are good examples of life cycles timed to food source availability or temperature. In temperate regions certain species of crane flies start disappearing from the top sediment and rocks in spring. They burrow deep into the sediment through summer. They then leave the stream to pupate on land, emerge as adults and lay eggs. By the time the larvae hatch, tree leaves are available in the stream for food.
Most species are bottom dwelling and many live in tubes or cases in the substrate.
They tend to be herbivore-detritivores in their feeding habits. Adult midges are generally short-lived and do not feed. Isopoda Aquatic Sow bugs Aquatic sow bugs, which inhabit a wide variety of shallow freshwater environments, are usually found under rocks or amid vegetation and debris. Most are omnivore-detritivores with a life span of about a year or less. Most scuds avoid light and during the daytime are found among vegetation or under rocks or debris.