A Marsh Fritillary butterfly. Steve Doyle has been working to save the endangered insects from extinction. Photo / 123RF
A Marsh Fritillary butterfly. Steve Doyle has been working to save the endangered insects from extinction. Photo / 123RF
A cage of caterpillars has prevented a house from being built after an enthusiast argued it would cast a shadow on their habitat.
Steve Doyle, 73, told planners in the UK that a new build would cast a shadow and starve the caterpillars he breeds of much-needed daylight.
He has been working to save the endangered Marsh Fritillary butterfly from extinction for the last 13 years in the garden behind his home in Durdar, Carlisle.
He told the city council's planning committee that cages would lose hours of sunlight every day if they gave permission for the new house.
In a submission he said: "The larvae are bred in a roughly one-metre cube cage in early spring before release into the wild into a pre-prepared habitat... by losing that two hours of sunlight in early spring I will have to stop breeding the larvae as they need all the sunlight they can get at that crucial time of the year when they come out of hibernation and regain body weight."
The Marsh Fritillary butterfly and cocoon. Photo / 123RF
The species was on the brink of extinction in Britain when he launched the project, starting work that eventually led to the re-establishment of 18 colonies across the county.
But the project would have been wiped out had councillors approved plans for a new house to be built that would devastating effect on the growth of the butterfly caterpillars.
He said the breeding programme continues to be necessary because colonies can suffer sudden and catastrophic population crashes.
Doyle's concerns were shared by Dr Keith Porter, who has also been a leading light in the battle to save the Marsh Fritillary butterfly.
Sunshine is vital for the caterpillars if they are to thrive, and the house as currently proposed would reduce the daily dose of sunlight by two hours, said Porter.
Both men said the application could be modified and the house re-positioned in order to avoid a critical loss of sunlight.
After discussing the planning application on Friday, members of Carlisle City Council's development control committee voted by eight votes to three to turn it down.
In its planning decision notice, the council states: "The proposed development by nature of its scale, height and location will have a negative impact by means of the unacceptable loss of sunlight on a breeding programme for a nationally important UK BAP (Biodiversity Action Plan ) priority species."
A planning case officer recommended the application be approved after a local architect wrote a report saying the resulting shadow would not significantly affect Doyle's garden.
In a statement before the meeting, Porter said: "A key requirement of Marsh Fritillary caterpillars is direct sunlight.
"They depend on sunshine as a means of raising their body temperature by basking - this is a part of their natural behaviour and enables them to grow much more rapidly than simple air temperatures would suggest.
"This is a behaviour I discovered when studying this species as part of my doctoral thesis and I have published several scientific papers on this almost unique behaviour.
"Insects are usually "cold-blooded" and cannot generate their own body heat; the Marsh Fritillary caterpillars raise their body temperature to 37C by basking.
