Poisonous caterpillars turning into butterflies, laying eggs

The hot and dry weather in the Netherlands last week were the ideal conditions for oak processionary butterflies to start crawling out of their pupa. The butterflies are expected to lay many eggs on oak trees across the country, which may result in more problems with the poisonous caterpillars again next year, AD reports.

"The oak processionary butterfly lives only a few days. They look for a male or female to mate with. The female lays her eggs in the tree, and that's it", Henry Kuppen of the Knowledge Center on the Oak Processionary Caterpillar said to the newspaper.

Over the past months, considerable effort was put into fighting the oak processionary caterpillars. Over 300 tons of caterpillar nests were cleared. But according to Kuppen, it's hard to say how many butterflies will crawl out of their pupa, how many eggs they will lay, or how many caterpillars the Netherlands will have to deal with again next year.

The oak processionary caterpillars get their name from their preference for oak trees and the fact that they travel in nose-to-tail processions. Their poisonous hairs can cause skin irritation and breathing problems in humans and animals. The butterflies do not cause these problems, because they do not have stinging hairs like the caterpillars. But as they crawled out of a nest covered in those hairs, there may be some left on the butterfly.

The butterflies will fly around and lay their eggs until around the end of September. The eggs will only hatch into caterpillars after the winter.