Description: A 4-6mm long very dark brown ground beetle with conspicuous red thorax in the typical form. Common under bark and in litter in wet woodlands. A coastal form has less contrasting thorax and lives on exposed rocks and dunes.

NI account: Common throughout Ireland in woodlands and one of the few small ground beetles to be found in this habitat. However, it is near the northern limits of its range in the British Isles, and is rarely recorded, for instance, in northern Scotland (Luff, 1998).

Ecology: Two distinct forms of the species have been found in Northern Ireland. Inland, a small variety with uniformly piceous elytra, occasionally paler along the suture, occurs in wet woodland and a range of other shaded habitats including gardens. It is found abundantly under bark on dead wood, a niche shared with few other Carabidae, particularly in cooler, highland areas. A larger form exists on coastal rocks with paler, brown to rufous elytra which are darkened only on the apex and sides. This form also exists very locally on arable soils near the coast, but not in shaded habitats. The two forms have not been observed to cohabit in our area, so reproductive isolation seems likely. Despite this, no clear morphological distinction other than size and colour of the elytra has been found. The wider distribution of these forms is presently unknown.

Distribution: A European Southern-temperate species (83) distributed from the British Isles southwards mostly, but not exclusively, near coasts in Europe, into the western Mediterranean with an outlying population in Greece, and on Atlantic coasts south to Macaronesia and N. Africa.

Similar Species: Ocys quinquestriatus: elytra with two setiferous punctures; pronotal base oblique laterally (Fig 57); uniform brown to reddish-brown, but usually with greenish metallic lustre

Key Identification Features:

• Small, elytra with a single setiferous puncture
• Sutural striae of elytra recurrent
• Terminal segment of palpi much reduced
• Pronotal base straight (Fig 56)
• Foreparts rufous, elytra darker, brown

Distribution Map from NBN: Ocys harpaloides at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Ocys harpaloides at iNaturalist World Species Observations database.

GBIF data for Ocys harpaloides | Classification: Insecta, Coleoptera, Carabidae, Ocys

Thumbnails for genus Ocys