Colymbetini

Adults of Colymbetini can be distinguished from other dytiscid tribes by combinations of morphological characters including features of the male genitalia and body shape. First-instar larvae possess diagnostic characters that allow generic-level identification; a key to genera based on larval morphology exists, though it excludes the monobasic New World genera Bunites and Hoperius due to unknown larvae.

Freshwater aquatic environments including ponds, lakes, and other standing or slow-moving water bodies. Specific habitat preferences vary by genus.

Widespread distribution with genera occurring in multiple continents. The genus Meladema is distributed in the western Palaearctic and Afrotropical regions. Rhantus has a Holarctic and Oriental distribution. Bunites and Hoperius are restricted to the New World.

Predatory, feeding on various aquatic invertebrates and small vertebrates typical of predaceous diving beetles.

Holometabolous development with egg, larval, pupal, and adult stages. Larvae are aquatic and predatory. First-instar larvae have been described for most genera and possess diagnostic morphological characters.

Predators in freshwater ecosystems, contributing to regulation of invertebrate populations and serving as prey for larger aquatic and terrestrial predators.

• HydroporiniAnother tribe of Dytiscidae; distinguished by differences in body form, male genitalia structure, and larval morphology.
• DytisciniLarger predaceous diving beetles in the same family; generally larger body size and different morphological proportions.

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Review of first-instar larvae of Colymbetini (Coleoptera: Dytiscidae), with a key to genera and phylogenetic analysis