Bug FAQLateral-lined Water Beetle
Tropisternus lateralis · Order: Coleoptera · Family: Hydrophilidae
Also called: Lateral-banded Water Scavenger Beetle, Water Scavenger Beetle
Adult eastern U.S. Tropisternus lateralis have uniformly dark wing covers and back plate with light borders. They make a rubbing sound when stressed, calling, or courting, and lay eggs in underwater cases. The species ranges from southern Canada through the United States, the Caribbean, South America to northern Chile and Argentina, and the Galápagos Islands.
Source: Wikipedia
How to recognize it
Adults are uniformly dark on the elytra and pronotum, with lighter edges.
Source: Wikipedia
Where it lives
They produce stridulating sounds during stress, calling, and courtship.
Source: Wikipedia
What it eats
Adults live mainly in water but must surface for air and are capable of flight. They avoid laying eggs in ponds that contain fish, which could eat any life stage.
Source: Wikipedia
Life cycle
Eggs are placed in cases beneath the water surface, and the larvae develop fully underwater. Adult beetles breathe air and can fly away from the water.
Source: Wikipedia
Where it comes from
Its range also includes the Caribbean, South America down to northern Chile and Argentina, and the Galápagos Islands.
Source: Wikipedia
Lookalikes
It is a hydrophilid beetle species that occurs across much of the Americas.
Source: Wikipedia
Where it is found in the US
Recorded in 48 of 51 states and DC. Most records: Texas, Florida, Illinois, California, Kansas, Mississippi, Kentucky, Oregon.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
How can I tell this beetle apart from similar species?
Look for uniformly dark wing covers and back plate with lighter-colored borders on the edges.
Source: Wikipedia
Where is the lateral-lined water beetle found?
It lives from southern Canada through the United States, the Caribbean, South America to northern Chile and Argentina, and the Galápagos Islands.
Source: Wikipedia
What does this beetle do when it is stressed or courting?
It produces a stridulating (rubbing) sound.
Source: Wikipedia
How does this beetle reproduce?
Females lay eggs in underwater cases, and the larvae develop completely in water.
Source: Wikipedia
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Tropisternus_lateralis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.