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Ellen RotherayPhD Research Student MSc Wildlife Management and Conservation, University of Reading (2006)
Supervisors:
Royal Society for the Protection of Birds (RSPB)
Start date: 1st March 2008
tel: +44 1786
466544 |
Research Project
Population dynamics, ecology and management of the BAP species Blera fallax (pine hoverfly) and Hammerschmidtia ferruginea (aspen hoverfly) (Diptera, Syrphidae)
Research funded by the Strategic Development Fund (University of Stirling), SNH and RSPB
This project involves investigation into two rare saproxylic hoverflies that are confined to Scotland. They are two of the most endangered insects in the UK.
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The pine hoverfly, Blera fallax |
The aspen hoverfly Hammerschmidtia ferruginea |
Saproxylic organisms are those that are dependant during some stage of their life cycle upon decaying wood of declining or dead trees, which means they are important decomposers and recyclers of energy and nutrients in natural woodlands. Both the pine hoverfly and the aspen hoverfly are specialist saprophages whose larvae depend upon decaying wood of specific species: Scots pine Pinus sylvestris and aspen Populus tremula respectively. Both are also Biodiversity Action Plan species and are listed in the UK Red Data Book as category 1 (endangered), but very little is known about these elusive animals.
In order to conserve Scottish wildlife and biodiversity, and manage what’s left of the ancient Caledonian forests, it is important to conserve insects such as these, and in order to do that they must be better understood.
The aspen hoverfly
As part of my MSc I carried out a research project on the aspen hoverfly which revealed previously unknown information on its ecology and behaviour. Included in the results were data on resource utilisation, adult food plants and longevity. This improved understanding enabled better, more informed management of the species.
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Capturing the aspen hoverfly in emergence traps proved a |
Fallen aspen tree under the bark of which the larvae feed |
The work on the aspen hoverfly will continue to fill in gaps to improve the management of extant populations. Similar methods and techniques will be used to research the ecology and population biology of the pine hoverfly.
The pine hoverfly
In 2007, the pine hoverfly was included in the SNH Species Action Framework as a species for conservation action. Habitat management began in 2003 on the basis of which a comprehensive set of actions were devised for the Framework. This research is designed to implement and monitor these actions, extend understanding and further develop management protocols.
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As part of the project each individual is marked with a paint spot (see blue spot on the thorax) which upon re-capture, allows data to be gathered on longevity, dispersal ability and population biology. |
Pine woodland: habitat of the pine hoverfly |
The pine hoverfly has a very limited distribution at just two sites in Scotland. Pine trees that have suffered from butt-rot fungus, or heart rot become weakened and often fall, breaking at the base to reveal the hollowed centre caused by the fungus. This hole fills up with rain water creating a “bacterial soup” upon which pine hoverfly larvae filter feed.
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Snapped pine tree revealing hollowed centre caused by heart rot (courtesy of Iain MacGowan, SNH) |
Holes also occur when stumps are left to decay after trees have been removed. As forests in Scotland have diminished and management policies have changed, suitable habitat for the pine hoverfly, and related saproxylic species has become drastically reduced.
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Felled pine stump with naturally rotted hole in the centre. |
Current habitat creation includes boring holes |
Detailed research is intended to establish habitat requirements of larvae and discover what are the oviposition preferences of gravid females. This includes assessment of the “bacterial soup” and habitat creation experiments designed to give insights into what determines the conditions which most favour pine hoverfly survival.
Molecular research is also anticipated to assess the genetic diversity within and between extant Scottish populations, historic and Scandinavian populations.
Publications
Rotheray E.L., MacGowan I., Rotheray G.E., Sears J., Elliott A. (2009) ‘The conservation requirements of an endangered hoverfly, Hammerschmidtia ferruginea (Diptera, Syrphidae) in the UK’ J Insect Conserv, 13:569-574 
Rotheray E.L. (2008) 'The ecology and conservation of the Aspen hoverfly' Aspen in Scotland: biodiversity and management, HAG, 12-14pp.
Rotheray E.L. (2006) ‘The Ecology, Abundance and Adult Requirements of the BAP Hoverfly, Hammerschmidtia ferruginea (Diptera, Syrphidae) in Relation to the Management of Aspen (Populus tremula). Unpubl. MSc thesis
Mitchell C., Vines J., Moore P., Wilkinson G. & Rotheray E. (2008) ‘Distribution and abundance of Whooper Swan Cygnus cygnus at RSPB Insh Marshes in 2005/06 and 2006/07’ RSPB unpubl. report to SNH, 16pp.
Rotheray E.L. (2003) ‘The oviposition preference of agromyzids on honeysuckle’. Unpubl. BSc dissertation.
