Brachyopa pilosa

[stuart]

Brachyopa pilosa Collin, 1939

Identification ease/difficulty: 3

Status

• Notable in Falk (1991)
• Rare in Shirt (1987)

Habitat indicator status

• H1 in Stubbs (1982)

Sources of information

• Page 180 in Stubbs & Falk (1983)
• Larval plate Pl. 10d in Rotheray (1993)
• Map here and page 20 in Ball & Morris (2000)
• Page 270 in Stubbs & Falk (2002)

[stuart]

Species account from Provisional atlas of British hoverflies, Ball & Morris, 2000.

Brachyopa pilosa Collin, 1939

Biology: The larvae inhabit runs or other accumulations of sap under the bark of Populus tremula in Scotland (Rotheray, 1996), but usually of *, Betula or occasionally Quercus in southern England. Adults have been found in association with Populus alba/canescens in the south-east. They are usually found sitting on tree trunks or vegetation near the larval habitat, but have also been taken at the flowers of Prunus padus in Sutherland (Entwistle quoted in Stubbs, 1996)

Distribution: This species is uncommon, with a markedly disjunct distribution. It is scarce but widespread in southern England with records north to Northamptonshire. In Surrey and the Windsor area (where it is rather more frequent than in other southern localities) it may have temporarily benefited from the large number of trees felled by the 1987 storm. In Scotland it has only been found in the Moray and Cromarty Firth areas (Rotheray, 1996)

[stuart]

Datasheet from the Review of Scarce and Threatened Diptera, Falk (1991).

BRACHYOPA PILOSA Collin NOTABLE

DISTRIBUTION Mainly recorded in southern England with strong populations in parts of the New Forest, Windsor Forest and beechwoods on the North Downs of Surrey. Also recently from Northants and East Ross in Scotland.

HABITAT Ancient broadleaved woodland. Closely associated with beech.

ECOLOGY The larvae probably develop under the bark of dying or recently dead large beech trees, especially recent windfalls, though some observations suggest that other trees such as oak and birch may also be used. Adults may be found at such sites or visiting spring blossom such as cherry and hawthorn and are recorded from late April to early June.

STATUS Widespread but very local, with about 20 known post 1960 sites and often locally abundant at Windsor Forest, the New Forest and the North Downs, but only occasionally recorded elsewhere in recent years, suggesting a loss of suitable sites. The Northants record was at a relatively young beech wood suggesting some ability to colonize new sites. However, the main strongholds at Windsor and the New Forests are under pressure through dead wood removal and lack of suitable tree regeneration. Status revised from RDB3 (Shirt 1987).

THREAT Clearance of beech woodland and especially of the large post-mature or recently dead trees. The shading out of rides and clearings within woods. Intensive forestry and the removal of dead wood is a major problem at Windsor and the New Forest.

MANAGEMENT Retain large post mature or recently dead trees ensuring their continuity in future. This requires large areas of woodland to ensure reasonably stable levels of the resource for larval development. Maintain rides and clearings with blossoms for adult feeding.