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Callicera rufa

 
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stuart
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Joined: 11 May 2005
Posts: 737
Location: Peterborough, UK

PostPosted: Sat May 28, 2005 5:39 pm    Post subject: Callicera rufa Reply with quote

Callicera rufa Schummel, 1842

Identification ease/difficulty: 2

StatusHabitat indicator statusSources of information
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Last edited by stuart on Wed Jun 01, 2005 9:19 pm; edited 1 time in total
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stuart
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Joined: 11 May 2005
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Location: Peterborough, UK

PostPosted: Sun May 29, 2005 8:40 am    Post subject: Species account from the Provisional atlas Reply with quote

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

Callicera rufa Schummel, 1842

Biology: The larvae occur in rot holes in Pinus filled with saturated debris, and have recently also been found in a similar situation in Larix (MacGowan, 1994). Adults are hardly ever seen, but when found are usually sitting on pine trunks or stumps or hovering nearby. Experiments have shown that rot holes created artificially by cutting into pine trunks with a chain-saw are utilised readily and can be occupied within two years

Distribution: This species, found only in the Caledonian pine forest of Scotland, was considered an extreme rarity until a survey was carried out by the Malloch Society, who, by searching for larvae rather than adults, succeeded in finding the species in most of the remaining forest areas which they examined (Rotheray & MacGowan, 1990)
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stuart
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PostPosted: Sun May 29, 2005 9:08 am    Post subject: Data sheet from Insect Red Data Book, Shirt, 1987 Reply with quote

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

Callicera rufa Schummel, 1841 ENDANGERED

Identification: Stubbs & Falk (1983), pp. 73 and 159, pl. 9:3.

Distribution: Ancient Caledonian pine forests on the eastern side of the Scottish Highlands. For map see Entwistle & Stubbs (1983), map 3. The population is believed to be small.

Habitat and ecology: The larvae live in partially water-filled rot-holes in large ancient pine treesPinus sylvestris. The needs of the adults are unknown, but they are normally seen on the trunks of live trees and on stumps.

Status: It has always been rare, but is now in danger of extinction. A large area of over-mature trees is required to ensure that some are in the right condition. It has a chance on two NNRs, but otherwise the outlook is bleak.Conservation: Present on two NNRs, but only one has long-term provision for the right habitat. There is a need to ensure that other sites have suitable forestry plans.Threats: Suitable ancient pines with the right type of rot-hole would seem to be very rare nowadays. Modern commercial forestry practice is changing the structure of native forests so that over-mature trees with rot holes will not be represented in the future.

Author: A. E. Stubbs, using adiditional information from Coe (1953).
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stuart
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PostPosted: Sun May 29, 2005 9:09 am    Post subject: Data sheet from National Review of Diptera, Falk, 1991 Reply with quote

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

CALLICERA RUFA (Schummel) RARE

DISTRIBUTION Records widely dispersed in the Scottish Highlands (Perthshire, Argyllshire, Aberdeenshire, Elgin, Easterness, West Ross, East Ross).

HABITAT Native pine woods and old Pinus sylvestris plantations. There is a requirement for living trees of at least 100 years age, with rot holes, for larval development.

ECOLOGY Larvae develop in water-filled rot holes as outlined above and may take five years or more before being ready to pupate. The rot holes in which they live are most common on trees with branches that grow upwards at sharp angles to the trunk, and in twin-trunked trees at the point where the two trunks meet. A few are formed where a branch breaks off at its extreme base. Rot holes are common in many pine woods but are inconspicuous. There can be in excess of 30 larvae per rot hole. Trees have to be at least 100 years old before they contain enough timber to support a rot hole. Rot holes take a long time to develop, but once formed they probably survive for many years, supporting successive generations of C. rufa. The adults are rarely seen and do not appear to visit flowers like most hoverflies. They are most frequently found sitting on the trunks of old pine trees and are recorded from June to August.

STATUS Prior to 1988 regarded as an endangered (RDB1) and declined species, almost exclusively on the basis of known adult records. Surveys by Dr G. E. Rotheray and I. MacGowan during the autumn of 1988 concentrated on finding the larvae and have demonstrated a wide distribution in the Scottish Highlands (16 out of 19 sites surveyed in 7 vice counties). This survey has also recognised the importance of old plantations in addition to native pinewoods. The species was regarded as being confined to the latter habitat until this time. The presence of C. rufa in small woods is probably due to the repeated colonisation of individual rot holes by successive generations. Status revised from RDB1 (Shirt 1987).

THREAT Clearance of native pine woodland, old pine plantations and removal of old trees. Where gaps in the age structure of trees is present at a site, the loss of rot holes for a period of time could lead to local extinction of the fly. It is unlikely that extensive commercial plantations with younger age classes of trees could support this species.

MANAGEMENT Maintain and encourage the presence of old pines, especially those that are well branched or have twin trunks. Ensure the age structure of trees at a site is suited to the continued presence of rot holes. Artificially created rot holes made by cutting into trees may help overcome this to some extent. Epiphytic growth of saplings and shrubs in rot holes can lead to their drying out and render them unsuitable to C. rufa, therefore this threat should be carefully watched for and acted against where appropriate.
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