Description: A moderate-sized (9-12.5mm) bronze-black ground beetle with prominent depressions and puncturations on the elytra (see also Blethisa multipunctata). Lives on silty, clayey soils at the margins of lakes and slow rivers. An Arctic species virtually unknown in Britain but widespread in north and west Ireland.

NI account: Widespread in the north and west, particularly Cos Down, Antrim, Sligo, Leitrim and Cavan. Scattered along the west coast from Donegal to Kerry but rare in the centre and east. A colony is recorded from Blessington in Wicklow. This is a high northern species which may be at some risk from the effects of climate warming. A colony at Inch Abbey on the River Quoile, Down is known to have died out recently, so some of the easterly localities may be vulnerable.

Ecology: Strongly hygrophilous with a preference for open muddy or silty lakeshores or where there is a mixture of open, preferably stony, ground and better vegetated areas. Probably an exclusively lowland riparian species here which is absent from heavily vegetated ecotopes such as interdrumlin fens, or from deep peat and altitudes above 200m. In Fennoscandia it occupies broadly similar habitats to those observed in Ireland (Lindroth, 1985) but in Alaska it has been observed in much more heavily vegetated flushes and peaty lakeshores in the tundra provinces (R. Anderson unpublished). This habitat is probably typical of its Siberian range also. Interestingly, the single Scottish mainland record is for a vegetated flush at 840m i.e. more typical of the high boreal populations, whereas the Orkney populations are mostly recorded from low-level stony lakeshores much as in Ireland (MacGowan & Owen, 1993).

Distribution: A circumpolar Arctic-montane species (16). In Europe mainly in northern Fennoscandia with outlying relict populations in the British Isles, a distribution which Lindroth (1985) described as 'Boreo-British'. In mainland Britain known only from an isolated site in Glen Affric, Inverness (MacGowan & Owen, 1993). Offshore it occurs in the Orkney Islands.

Similar Species: Blethisa multipunctata: With punctate foveae but with nine striae; pronotum not cordate (Fig. 6); upper surface bronze but with greenish edges to the elytra and pronotum

Key Identification Features:

• Elytra with punctate foveae on 4th and 6th striae
• Ten elytral striae
• Pronotum cordate (Fig. 5)

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

iNaturalist: Pelophila borealis at iNaturalist World Species Observations database.

GBIF data for Pelophila borealis | Classification: Insecta, Coleoptera, Carabidae, Pelophila

Thumbnails for genus Pelophila