Ground Beetles of Ireland

Bembidion geniculatum

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Bembidion geniculatum
© Roy Anderson
Bembidion geniculatum
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(Maps updated 30th November 2009)

Bembidion geniculatum Heer, 1838

Description: 4.5-5.5mm long black ground beetle with bluish or greenish reflections, found on gravel or shingle banks by rivers. Very similar to B. atrocoeruleum but more local and northern.

World Distribution: A European Boreal-montane species (43) with a restricted European range and recorded from the Alps, the Pyrenees and the Balkans. Also found on hill land in the north and west of the British Isles.

Irish Status: Added to the Irish list from a streambank at Glenariff, Antrim (Speight et al. 1983). Three further sites have been found in the Sperrin Mountains, Londonderry. Widely but locally distributed in northern Britain, principally in the north Pennines (Luff 1998).

Ecology: Sowig (1986) suggests that because of very similar substrate and humidity preferences, geniculatum and atrocoeruleum avoid competition by living at different altitudes in the Black Forest. In Ireland, geniculatum has been found with B. atrocoeruleum in one locality, and with B. tibiale at the other three, although, on average, it is recorded from slightly higher altitudes (100-300m) than atrocoeruleum. B. geniculatum also appears to have the more northern range of the two in Ireland, and searches of seemingly suitable montane streambanks in the southern and western counties of Kerry, Galway and Mayo have so far been unsuccessful.