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Trechus obtusus
Carabidae overview
Key to genera
Identification:
Small (3.5 - 3.6 mm); medial area between the frontal furrows on the head is narrower than lateral area between furrow and eye; pronotum broad basally; basal sinuation of lateral margin shallow or absent; basal angle is distinctly obtuse; sutural stria of the elytra recurrent at apex and prolonged forwards on the fifth stria; body brown or slightly piceous; legs, palpi and antennal scape brownish yellow; second through eleventh antennomeres slightly darker.
Range:
Introduced from Europe where it has a Euro-Mediterranean distribution. Presently expanding its range on the western coast of North America north to Queen Charlotte Islands and Prince Rupert area, and south to central California. This species is restricted to areas west of Cascades and Sierra Nevada.
Natural History:
Found only in lowlands near disturbed, synanthropic sites. Dimorphic in the Pacific Northwest; some specimens have well developed wings and others are brachypterous. On TESC campus, found in a large area of marshy meadow and scotch broom and one specimen was collected from a grassy road shoulder. The fourth most abundant species sampled during the fall season.
References:
Kavanaugh, D. H. 1992. Carabid beetles (Insecta: Coleoptera: Carabidae) of the Queen Charlotte Islands, British Columbia. Memoirs of the California Academy of Sciences Number 16. California Academy of Sciences, San Francisco, California, USA.
Lindroth, C. H. 1961-1969. The ground beetles (Carabidae excl. Cicindelinae) of Canada and Alaska. Parts 1-6. Opuscula Entomologica xlviii + 1192 pp.
Last updated Friday, July 21, 2006, by Lisa Ferrier
