‘Freezing’ the decline of an iconic British butterfly

The British Swallowtail butterfly (Papilio machaon britannicus) is found exclusively in East Anglia, predominantly in the Norfolk Broads, but its survival is threatened by habitat loss, climate change and genetic erosion due to its limited geographical range.

Since the 1970s, 80% of the UK’s butterflies have declined in their abundance or distribution. The British Swallowtail, a subspecies of the Old World Swallowtail, is classified as vulnerable on the GB Red List, with its population having declined by 57% in the last 20 years.

Together with our research partners at Anglia Ruskin University (ARU) and Jimmy’s Farm and Wildlife Park, we are exploring whether cryopreservation could help in their conservation.

Jimmy’s Farm and Wildlife Park houses a thriving captive population of a genetically similar but far more abundant species than the British Swallowtail, Papilio machaon gorganus. The eggs of these more abundant butterflies will serve as the model for our new research.

The aim of this project is to develop cryopreservation techniques to safely freeze fertilised swallowtail eggs which are laid during the breeding season. We will then attempt to rear butterflies from the frozen eggs, comparing their development and reproductive success with control groups of butterflies from non-frozen eggs. If our method proves effective, we hope that the eggs of the British Swallowtail can then be stored to support long-term conservation strategies, such as breeding programmes and reintroduction efforts.

Our research partner, Dr Alvin Helden of Anglia Ruskin University, said:

“Although this has been an excellent summer for our native butterflies, the long-term picture for the British Swallowtail is one of decline.

Our project will combine fieldwork and lab research to see if we can establish a reliable method for preserving the British Swallowtail’s genetic material by using its closely related, but less endangered, European cousin. Cryopreservation is a promising tool for supporting conservation efforts, but we believe this is the first time it has been attempted with butterflies.

We will be investigating whether the caterpillars are as healthy and whether the butterflies are as productive as those that come from eggs that haven’t been frozen. If successful, this research has the potential to help safeguard the future of the British Swallowtail and significantly contribute to butterfly conservation in general.”

Jimmy Doherty, Founder of Jimmy’s Farm & Wildlife Park, Visiting Professor at ARU, and Ambassador for Nature’s SAFE, said:

“Conservation is at the heart of everything we do at Jimmy’s Farm & Wildlife Park, from managing breeding programmes to supporting pioneering scientific research.

Our commitment to the science of entomology, and especially butterfly conservation, means this project is a natural fit for us. Partnering with ARU and Nature’s SAFE allows us to apply our expertise to work that could make a real difference in protecting the British Swallowtail for generations to come.”

This project holds significant importance for the development of cryopreservation techniques – not only for the British Swallowtail, but across pollinators and invertebrates as a whole.

Building capability in this area provides the opportunity to create impact for conservation, food production and biodiversity preservation – the critical triad for human and planetary health. Nature’s SAFE is delighted to be working closely with ARU Writtle and our conservation partners at Jimmy’s Farm & Wildlife Park.