Swimming-adaptation
Guides
Dytiscidae
predaceous diving beetles, diving beetles
Dytiscidae, the predaceous diving beetles, is a family of aquatic beetles containing over 4,000 described species. Adults range from 0.9 mm to 4.75 cm in length, with most species between 1–2.5 cm. They are characterized by enlarged, flattened hind legs adapted for swimming and a streamlined, oval body shape that reduces drag underwater. The family exhibits remarkable chemical ecology, producing unique defensive steroids found nowhere else in the animal kingdom. Larvae, known as "water tigers," are elongate predators with sharp, pincer-like mandibles that inject digestive enzymes into prey.