In July, caterpillars of the rare and endangered large blue butterfly were reintroduced to areas managed by the Danish Nature Agency in Jydelejet, north of Klinteskoven, where the species disappeared in the 1970s. The reintroduction was carried out by experts from the Royal Entomological Society, who have more than 40 years of experience in handling and breeding the species.
Sarah Meredith from the Royal Entomological Society captured the moment when an unsuspecting red ant discovers a caterpillar and carries it back to the ant nest. There, it will consume more than 300 ant larvae before pupating and developing into a beautiful butterfly.
Credit: Sarah Meredith
The large blue butterfly has a highly unusual life strategy. At just 2–3 weeks old, the caterpillar switches from feeding on the flowers of wild marjoram or thyme to being adopted by a red ant, after which it feeds on ant brood. The caterpillars were released at this critical transition from herbivore to carnivore.
The wild marjoram, which serves as the butterfly’s food plant, is collected from Høvblege after the adult butterfly has laid its eggs on the plant.
In the home laboratory, the flowers are placed in water to keep them fresh while the caterpillar develop.
Credit: Mads Tolstrup
The reintroduction is being carried out in collaboration with Vordingborg Municipality and Ravn-Nature as part of the LIFE Orchids nature project. The aim is to strengthen the population and create new habitats for the critically endangered large blue butterfly.
David Simcox from the Royal Entomological Society, separates the caterpillar shortly after they have hatched.
If several caterpillar are found on the same plant, it is important to separate them, as they otherwise display cannibalistic behaviour.
Credit: Mads Tolstrup
A caterpillar in its 4. instar, ready for reintroduction. When, after 2–3 weeks, the caterpillar transitions to living as a parasite of the red ant, it is released into its new habitat in Jydelejet.
Credit: Mads Tolstrup
The moment when red ants pick up a caterpillar and carry it back to their nest. The caterpillar will live in the ant nest until the following summer.
Credit: Martin Vestergaard
LIFE Orchids is being implemented in close collaboration with the project’s other partners: Klintholm Estate, GeoCenter Møns Klint, ELO and EUROSITE. The project is funded by the Aage V. Jensen Nature Foundation, the 15 June Foundation, the Danish Nature Fund and the EU LIFE Nature programme.
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