Beneath oak canopies, in an orchard full of hundred-year-old apple trees, excited exclamations rose from a group of moth enthusiasts last week. The Cambridgeshire Moth Group had just trapped a dark crimson underwing, a species so rare that none of them had ever seen it before. Indeed, the colourful invertebrate is only usually ever found in the New Forest and is considered nationally scarce. Anna Gazeley, who owns Coton orchard, rushed down to take a look. “At first, it just looked like a normal moth,” she said, “but the moth group was really excited, geeking out, so I kind of fed off their excitement and bent down to take a picture. Then, it opened its wings and I understood – it was really beautiful.” The moth group makes a regular appearance at Gazeley’s orchard. Her land, pesticide-free since her father, Albert, bought it in 1996, supports more than 200 invertebrate species, of which 14 are considered nationally scarce, including eight beetles, two bees and four moths – now, five if the underwing, thought to be a migrant, decides to breed. They enjoy the wide range of fruit trees and wildflower meadows found in the orchard, and the land does not require ploughing so the soil is rich with life. Traditional orchards are important for biodiversity. Fruit trees tend to age faster than other species, such as oak trees, so they harbour the important fungi and nooks and crannies that invertebrates and birds like. And, of course, birds and insects love to feed on fallen fruit. It is estimated around 90% of England’s traditional orchards have been lost since the 1950s due to development and modern fruit production, where the trees are kept young and small, pesticides are used and the fruit is all harvested rather than being able to fall. Ben Greig from the Cambridgeshire Moth Group was one of the people who caught the stunning creature. He said: “We trap moths at Coton orchard regularly as it offers a variety of habitats – meadow, orchard, mature trees, scrub – and has been pesticide-free for decades. On the night of 14 August we set four traps. It was a warm, cloudy night with little wind: perfect conditions. In the morning of the 15th we spent several hours identifying and counting the hundreds of moths before releasing them safely. At the very bottom of the last trap was one of the rarest moths we had ever seen, the dark crimson underwing – Catocala sponsa. A large moth, it is cryptically coloured above but when disturbed it flashes its bright crimson underwings to startle and frighten off predators.” Although the moth is likely to be a migrant from the European continent, Gazeley hopes she will one day welcome a breeding population: “This moth, it likes ancient woodlands, and so between the semi-mature oak and the dead wood created by the apple trees, it’s a hospitable environment for it to potentially breed.” Greig added: “The caterpillars feed on the buds, catkins and leaves of sessile and English oak trees so dark crimson underwings need mature or ancient oak woodland to thrive. The loss of mature woodland in the UK is a major cause in its decline here. We reflected on the fact that we were admiring this rarity directly in the path of the proposed C2C busway, the plans for which are still under way yet also still has fierce local resistance.” Gazeley has been campaigning against the busway Greig mentioned; it would bisect her orchard, and she argues the disturbance would destroy its fragile ecosystem and rich biodiversity. Figures including the broadcaster Chris Packham and economist Partha Dasgupta have written in support of her plea to Cambridge council. The proposed route would serve 6,000 new homes. Campaigners say that instead of a separate busway, the existing road could be widened. Finding the moth was unlikely to make a huge difference to the campaign, she said, as there were already so many rare species supported by her orchard. “We’ve got 29 red list species. Does one more make a difference? Probably not, but it makes a huge difference to morale, and it’s morale driving us forward, because we don’t have much else.”