Myolepta potens

[stuart]

Myolepta potens (Harris, [1780])

Identification ease/difficulty: 5

Status

• Endangered in Falk (1991)
• Endangered in Shirt (1987)
• BAP priority in UK BAP (1995)

Habitat indicator status

• H2 in Stubbs (1982)
• Listed as a saproxylic indicator in Speight (1989)

Sources of information

• Page 184, Pl. 7, fig 2 in Stubbs & Falk (1983)
• Map here and page 6, 96 in Ball & Morris (2000)
• Page 276, Pl. 7, fig. 2 in Stubbs & Falk (2002)

[stuart]

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

Myolepta potens (Harris, 1780)

Biology: The larvae live in water-filled rot holes in ancient deciduous trees, including *, Quercus and Populus and probably take several years to reach maturity. Little is known of the adult habits, but presumed similar to M. dubia

Distribution: See introduction for a summary of the history of this very rare species in Britain. Only known from two very restricted areas in Somerset and most of the 20 known British specimens date from the 1940s. It was last found in 1961 and is feared extinct. Appears to be a rare species throughout its known range

[stuart]

Datasheet from the Insect Red Data Book, Shirt (1989).

Myolepta potens[i] (Harris, 1780) ENDANGERED

Identification: Stubbs & Falk (1983), pp. 92 and 184, pl. 7:2.

Distribution: Only recorded from a small area near Bristol and the Shapwick/Edington area of Somerset. For map see Entwistle & Stubbs (1983), nap 22.

Habitat and ecology: Unknown. It is assumed to be a woodland species, breeding in dead wood (in common with[i]M. luteola, whose larvae are adapted to live in wet rot-holes).

Status: Only a few specimens are known, all found in the 1940s. At least one of its former woods has been coniferised. This is one of four British hoverflies which have not been confirmed as occurring in Britain in the post-1970 period.

Author: A. E. Stubbs.

[stuart]

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

MYOLEPTA POTENS (Harris) ENDANGERED

DISTRIBUTION All records are from a small area near Bristol (Coombe-Dingle/Blaise Castle) and in the Shapwick/Edington district of Somerset.

HABITAT Old broadleaved woodland, probably with a requirement for old or diseased trees with rot holes.

ECOLOGY Unknown, though presumably living in rot holes of trees like the related M. luteola. Adults recorded from mid May to early June.

STATUS All records are from the mid 1940s and it has not been found since, despite numerous visits to the area, suggesting it is either now very rare or extinct. Blaise Castle (Coombe-Dingle) has undergone some changes since these records, though whether this has affected the dead wood fauna is uncertain.

THREAT Clearance of the known sites for agriculture or intensive forestry and removal of the old or diseased trees and dead wood.

MANAGEMENT Retain any old or diseased trees especially those with obvious wounds and rot holes, also dead wood and ensure a continuity of these in the future.