Ground Beetles of Ireland

Dyschirius obscurus

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Dyschirius obscurus
© Roy Anderson
Dyschirius obscurus
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(Maps updated 30th November 2009)

Dyschirius obscurus (Gyllenhal, 1827)

Description: Small (3.5-4.5mm) dull bronze-black fossorial ground beetle, confined to bare sand on Lough Neagh in Ireland. Usually associated with Bledius subterraneus in its Irish habitats.

World Distribution: A European, or possibly Eurosiberian, Boreo-temperate species (53), scattered over north, west and central Europe to the Caspian Sea, but mostly near sea coasts.

Irish Status: Confined to the shores of Lough Neagh where it was first found by Haliday (Dawson 1854). Several adventitious colonies have recently been recorded in gravel pits in south-east England, having come in from Europe. Unknown elsewhere in the British Isles.

Ecology: Stenotopic for fine sand habitats which are stabilised by moisture. In this respect its requirements are similar to those of D. impunctipennis, although the ranges of the two do not overlap in Ireland. On Lough Neagh the usual oxyteline associate is Bledius subterraneus Erichson, but it has also been found with Bledius fuscipes agg. (Anderson, 1979). A recent survey of Lough Neagh habitats has indicated that association of D. obscurus with Bledius is not obligatory. Colonies of Bledius spp. were found on only six beaches out of a total of sixteen on which large populations of D. obscurus were present (R. Anderson unpublished). Some flexibility with regard to food preferences seems likely in these circumstances. An obligatory reliance on Bledius is discounted by Thiele (1977).