The dark pimpernel blue has not been seen in the Netherlands this year. Volunteers from the Butterfly Foundation have been looking for the butterfly for days, but they fear that the butterfly species has completely disappeared from our country. And that has everything to do with a mowing session four years ago in Limburg.
Until 1970, the dark pimpernel blue was doing fine in the Netherlands. Then the butterfly disappeared due to the intensification of agriculture, but 31 years later the species suddenly reappeared in Limburg from Germany.
Since then, the Butterfly Foundation has been monitoring the butterfly population. The species lives on roadsides and along ditch banks where the large pimpernel grows. The butterfly lays its eggs on that plant. The caterpillars that crawl out of it first live on the large pimpernel and then leave the plant. “Once on the ground, ants drag the caterpillars to the brood chambers in their ant nest. There, the caterpillars live on ant larvae,” says Irma Wynhoff of the Butterfly Foundation. The caterpillars hibernate in the nest and pupate there. After this metamorphosis, the butterflies in turn fly to a large pimpernel to lay eggs.
Mowed too early
Without the plant, the butterfly cannot survive. It is therefore crucial that the plant remains standing until the caterpillar moves from the plant to the ant nest. “Therefore, mowing is not allowed between June and September,” says Wynhoff. But that went wrong in July 2020. A verge in Limburg was mowed at that time commissioned by the Limburg Water Board, causing the butterfly’s last habitat in the Netherlands to disappear.
‘The end of the butterfly for now’
The Butterfly Foundation counted fewer dark pimpernel blues every year. In recent years, volunteers searched for the butterfly for days. Last year, they saw five. “That is already very few, but this year we did not find a single one.” Because the monitoring was so intensive, Wynhoff is certain: “This means the end of the butterfly in the Netherlands for the time being.” Progress has been made in the habitat of the dark pimpernel blue, which means that the butterfly may fly around the Netherlands again in the future.
