Bug FAQCybister explanatus
Cybister explanatus · Order: Coleoptera · Family: Dytiscidae
Adult Cybister explanatus beetles are about 24.5 to 29 mm long, while their larvae measure 13 to 15.2 mm. They live in still-water habitats such as ponds, lakes and valley pools across western North America and parts of Middle America. These predaceous diving beetles are carnivorous and the adults are eaten roasted or as taco filling in Mexico.
Source: Wikipedia
How to recognize it
They have sharp points on the hind-leg metafemora and a yellow lining along the edges of the elytra and pronotum.
Source: Wikipedia
Size
Adults range from 24.5 to 29 mm; larvae are 13 to 15.2 mm long.
Source: Wikipedia
Where it lives
As a predaceous diving beetle, it lives in aquatic, still-water environments like ponds and lakes, and also in valley habitats.
Source: Wikipedia
What it eats
It plays an important carnivorous role in its ecosystem. Adults are edible and are roasted or used as a taco filling in Mexico.
Source: Wikipedia
Life cycle
Male beetles have modified tarsi on their legs compared with females. The species is fairly consistent, with most variation seen in size and coloration.
Source: Wikipedia
Where it comes from
It belongs to the Nealocomerus subgenus, which groups Nearctic Cybister species.
Source: Wikipedia
Lookalikes
It looks similar to Cybister ellipticus.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: California, Nevada, Utah, Illinois.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What does Cybister explanatus eat?
It is a carnivore that helps control other aquatic organisms, and the adults are also eaten roasted or as taco filling in Mexico.
Source: Wikipedia
Where can I find Cybister explanatus?
Look for it in still-water habitats such as ponds, lakes and valley pools, especially in western North America and parts of Middle America.
Source: Wikipedia
How can I tell Cybister explanatus apart from similar beetles?
It has sharp points on the hind-leg metafemora and a distinctive yellow lining on the edges of the elytra and pronotum, unlike many other diving beetles.
Source: Wikipedia
Same family (Dytiscidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Cybister_explanatus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-29 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-29.