Berosus affinis

Description

A small (3.5 to 4.5 mm) water beetle. The elytra have a straw ground colour with a prominent pair of dark spots near the suture and additional spots nearer the apex. The black head, bulging eyes and broad dark patch on the pronotum are particularly noticeable. This dark pronotal patch may have a pale central line but this doesn't extend beyond half way. The elytral interstices are flat.

Similar Species

Berotus luridus is generally darker so the elytral spots are less noticeable.The dark pronotal patch has a pale median line that extends at least half way down. The elytral interstices (strips between the striae) are raised into ridges (flat in B. affinis).

Identification difficulty
Recording advice

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Habitat

Ponds and other marshy habitat types.

When to see it

All year round.

UK Status

Widespread in the southern half of Britain but rather local.

VC55 Status

Rarely recorded in Leicestershire and Rutland with only a handful of records.

Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2025+ | 2020-2024 | pre-2020

UK Map

Species profile

Species group:
Beetles
Kingdom:
Animalia
Order:
Coleoptera
Family:
Hydrophilidae
Records on NatureSpot:
3
First record:
13/06/2021 (Skevington, Mark)
Last record:
14/09/2022 (Nicholls, David)

Total records by month

% of records within its species group

10km squares with records

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