Ontogenetic-diet-shift
Guides
Cybister
Giant Diving Beetles
Cybister is a genus of large predaceous diving beetles (Dytiscidae) distributed across all continents except Antarctica. Adults range up to 43 mm in length, with some species among the largest diving beetles. The genus comprises approximately 98 species organized into four subgenera. Both adults and larvae are aquatic predators, with larvae of some species known to prey on vertebrates including tadpoles and small fish.
Hydrophilus
Giant Water Scavenger Beetles
Hydrophilus is a genus of large aquatic beetles in the family Hydrophilidae, commonly known as giant water scavenger beetles. The genus comprises approximately 48 species arranged in three subgenera: Hydrophilus, Dibolocelus, and Temnopterus. These beetles are among the largest aquatic insects in their range, with some species reaching substantial size. Members of this genus are fully aquatic as adults, possess the ability to disperse by flight, and exhibit distinct feeding mode shifts during development—carnivorous larvae transition to omnivorous adults. Several species are rare or endangered in parts of their range, including the great silver water beetle Hydrophilus piceus in Britain.