Bromius obscurus (Linnaeus, 1758)
Images
Description
Size: 5-6mm
Basic colour: Black, covered in dull yellow-grey pubescence (basal 4 antennal segments orange-red)
Pattern colour: None
Number of spots: None
Pronotoum: As basic colour
Leg colour: As basic colour
Following mention from Lincolnshire in 1831, 'rediscovered' in Cheshire in 1979. Well established in a single 10km square on the Cheshire/Staffordshire border around the Bosley area. Outside the UK, a widespread Holarctic species.
Biology
Status: Endangered (RDB1)
RDB Category: Endangered (RDB1)
Habitat: Known from a disused railway embankment (light sandy soil by a river)
Host plant: Rosebay willowherb (Chamerion angustifolium), other willowherbs (Epilobium spp.), grape-vine (Vitis vinifera) and giant butterbur (Petasites japonicus)
Overwintering: Larvae overwinter, developing slowly at roots of host plants, adults emerging in May.
Food: Adults feed on host plant leaves, larvae feed in groups on the roots.
Other notes: Adults parasitised by larvae of the trombidiid mite Atomus parasiticus.