Members of this family are found on every continent, except Antarctica and Australia, being more common in the tropics. Long-toed water beetles are named for their extended claws. Adults have dense hairs, which allow the beetles to breathe while underwater.
When the pupae complete the imago stage of their life cycle, they move towards running water, and may be attracted to lights.
Despite being referred to as aquatic insects, the beetles are unable to swim, clinging to detritus that float. All long-toed water beetles feed on plants that are in the water, but the larvae are generally terrestrial. Stygoparnus is the only genus in the family in which both the larvae and adults are aquatic.
Source: Wikipedia
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