Predaceous diving beetles are aquatic beetles found throughout freshwater habitats around the world. There are over 4000 species in this family. The name Dytiscidae comes from the Greek “dytikos”, meaning “able to dive”.
These beetles are divided into several subfamilies, classified into various genera.
1. Agabinae
Agabinus
Agabus
Agametrus
Andonectes
Hydronebrius
Hydrotrupes
Ilybiosoma
Ilybius
Leuronectes
Platambus
2. Colymbetinae
Anisomeria
Senilites
Carabdytes
Bunites
Colymbetes
Hoperius
Meladema
Melanodytes
Neoscutopterus
Rhantus
Rugosus
3. Copelatinae
Agaporomorphus
Aglymbus
Copelatus
Exocelina
Lacconectus
Liopterus
Madaglymbus
Rugosus
4. Coptotominae
Coptotomus
5. Cybistrinae
Austrodytes
Cybister
Megadytes
Onychohydrus
Regimbartina
Spencerhydrus
Sternhydrus
6. Dytiscinae
Acilius
Aethionectes
Austrodytes
Dytiscus
Eretes
Graphoderus
Hydaticus
Hyderodes
Megadytes
Miodytiscus
Notaticus
Onychohydrus
Regimbartina
Rhantaticus
Sandracottus
Spencerhydrus
Sternhydrus
Thermonectus
Tikoloshanes
7. Hydrodytinae
Hydrodytes
Microhydrodytes
8. Hydroporinae
Africodytes
Agnoshydrus
Allodessus
Allopachria
Amarodytes
Amurodytes
Andex
Anginopachria
Anodocheilus
Antiporus
Barretthydrus
Bidessodes
Bidessonotus
Bidessus
Boreonectes
Borneodessus
Brachyvatus
Brancuporus
Canthyporus
Carabhydrus
Celina
Chostonectes
Clypeodytes
Coelhydrus
Comaldessus
Crinodessus
Darwinhydrus
Deronectes
Derovatellus
Desmopachria
Dimitshydrus
Ereboporus
Etruscodytes
Fontidessus
Geodessus
Gibbidessus
Glareadessus
Graptodytes
Haideoporus
Hemibidessus
Heroceras
Herophydrus
Heterhydrus
Heterosternuta
Hovahydrus
Huxelhydrus
Hydrocolus
Hydrodessus
Hydroglyphus
Hydropeplus
Hydroporus
Hydrovatus
Hygrotus
Hyphoporus
Hyphovatus
Hyphydrus
Hypodessus
Iberoporus
Incomptodessus
Kakadudessus
Laccornellus
Laccornis
Leiodytes
Limbodessus
Liodessus
Lioporeus
Megaporus
Metaporus
Methles
Microdessus
Microdytes
Morimotoa
Nebrioporus
Necterosoma
Neobidessodes
Neobidessus
Neoclypeodytes
Neoporus
Oreodytes
Pachydrus
Pachynectes
Papuadessus
Paroster
Peschetius
Petrodessus
Phreatodessus
Platydytes
Porhydrus
Primospes
Pseuduvarus
Psychopomporus
Pteroporus
Queda
Rhithrodytes
Sanfilippodytes
Scarodytes
Schistomerus
Sekaliporus
Sharphydrus
Siamoporus
Siettitia
Sinodytes
Spanglerodessus
Sternopriscus
Stictonectes
Stictotarsus
Stygoporus
Suphrodytes
Tepuidessus
Terradessus
Tiporus
Trichonectes
Trogloguignotus
Tyndallhydrus
Typhlodessus
Uvarus
Vatellus
Yola
Yolina
9. Laccophilinae
Africophilus
Agabetes
Australphilus
Japanolaccophilus
Laccodytes
Laccophilus
Laccoporus
Laccosternus
Napodytes
Neptosternus
Philaccolilus
Philaccolus
Philodytes
10. Lancetinae
Lancetes
11. Matinae
Allomatus
Batrachomatus
Matus
Physical Description and Identification
Adult
Size: 0.4–1.0 in (1 – 2.5 cm). The largest known beetles are the Dytiscus latissimus at 1.8 in and Megadytes ducalis at 1.9 in, while Limbodessus atypicali is the smallest at 0.035 in.
Color:They are brown, olive, or shiny black, with some having yellow markings on their elytra.
Other Characteristic Features: Their bodies are streamlined and narrower towards the head. The position where they are most often seen underwater is keeping their head down while their abdomen remains visible through the surface.
Larva
The larvae are brown or olive and nicknamed “water tigers” owing to their big appetites. They have sharp mandibles for grabbing and holding on to prey and a tail covered with setae letting them cling to grasses and similar plants underwater.
Their bodies are elongated, with six legs protruding from the thorax. These legs are also covered with hairs, similar to the tail.
Pupa
Once they are mature enough, the larva emerges from the water and burrows themselves into the mud of the shoreline to pupate.
Egg
These beetles lay their eggs inside the egg mass of frogs, with the larva hatching around 24 hours after the tadpoles.
Quick Facts
Lifespan
Few years
Distribution
Worldwide
Habitat
Freshwater habitats, like brooks, rock pools, lakes, streams, etc.
Seasons active
Late summer
Predators
Dragonfly larvae, frogs, some birds like herons, and fish
Diet
Primarily insects, but also tadpoles and small fish
Identifying the Damage Caused by Them
These beetles are not harmful to humans.
Did You Know
As per Cherokee legend, a diving beetle rose from the “liquid chaos” and, upon finding no place to rest, brought back a ball of mud that would spread out to become the landmasses on Earth.
Some mites can be found under the elytra of these beetles, spending their entire lives there.
