Rare pine hoverfly to be reintroduced to the Cairngorms

Little insect could have big future after 60 years
June 2009. An insect on the verge of extinction in Britain looks set to return to the Cairngorms forest for the first time in 60 years after a unique reintroduction project.

Just 250 flies left

The pine hoverfly, the size of a small bumble bee, is in a perilous state due to its specialised breeding requirements. It needs rotting tree stumps with standing water, but a lack of old trees means it may now number just 250 individuals in Scotland.

The reintroduction has seen 20 of the attractive red and black insects reared at a specially constructed field laboratory in the grounds of Rothiemurchus Estate in the heart of the Cairngorms National Park. It is hoped they will breed at artificially created tree stumps nearby for the first time in 60 years.

The species reintroduction is the result of joint working between Scottish Natural Heritage, Rothiemurchus Estate, and PhD scientist Ellie Rotheray. She is leading insect research at a home-made laboratory in the estate.

Habits unknown to science

Though the work will contribute to current understanding of this fascinating creature, much of the pine hoverfly's mating habits and diet remains unknown. Further scientific studies are required to learn more about this rare insect. The habitat restoration is also a result of Rothiemurchus Estate's Forest Plan, which ensures that the natural forest is managed in a way that enhances biodiversity. The SNH role is led by Iain MacGowan.

Welcoming the reintroduction, Minister for Environment Roseanna Cunningham said: "Losing any species can be disastrous for biodiversity and can also create subsequent negative effects in the long term. However, while the pine hoverfly's demise is preventable, their loss would be unforgiveable."

Rothiemurchus Forest is a wonderfully rich network of habitats and wildlife

Johnnie Grant, Rothiemurchus owner, said: "We are delighted to have been able to help SNH, Ellie and Iain achieve this success. Rothiemurchus Forest is a wonderfully rich network of habitats and wildlife. Enhancing biodiversity is part of good land management and helps create the superb landscapes in which so many people enjoy being active.

"This estate management strategy is providing an improving habitat for a species which has been absent since around 1950 possibly because of a lack of large tree stumps due to the cessation of cutting following extensive wartime fellings. The hoverfly is a key species that will be monitored from now on."

Work to conserve the species and manage favourable habitat is being carried out by Scottish Natural Heritage as part of the Species Action Framework (SAF). This work has seen SNH liaise with landowners, the Malloch Society, RSPB Scotland and Forest Research to reintroduce the species to favourable habitats.

Only two sites known in Britain

Iain MacGowan of SNH said: "With only two sites known in Britain, the population of the pine hoverfly is in a fragile state and we need to take action now to save it for future generations. The pine hoverfly disappeared from this part of Strathspey after the intensive felling of native pinewoods during World War II and if all goes to plan under our habitat restoration work it will be the first time it has been here in 60 years.

"This site at Rothiemurchus Estate near Aviemore is just one of a few locations in the UK suitable for the insects and we are grateful to the estate for their efforts in ensuring that this species is able to gain a foothold here through their habitat restoration work.

Victim of its own specialised breeding cycle

"It could be argued the pine hoverfly is a victim of its own specialised breeding cycle as it needs large, old rotten tree stumps more than 40 centimetres in diameter to breed. But the lack of such large trees in native pinewoods is a problem not only for this hoverfly but also for other insects and birds. We now need to think about managing our forests to help this little insect as well as all the better known species.

"That is why we and Rothiemurchus Estate have prepared a site for the reintroduction by cutting holes into stumps and filling them with wood chips. These, when filled with rainwater, mimic the natural rotting stump habitat in which the pine hoverfly larvae live."

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