This week, while working on-site in Oxfordshire and conducting a walkover survey for nesting birds, I encountered something remarkable. I noticed unusual defoliation in a row of willow trees, and moth webbing covering the trees.
As you can see from these photographs, the Willow trees were covered in
ghostly silken webbing
Upon closer inspection, I was astonished to find thousands of Willow Ermine caterpillars; these striking and obvious webs were hiding them in every tree.
While the caterpillars and their webs can be alarming, they are generally harmless and tend to disappear by summer, with the trees usually recovering. Ermine moth caterpillars hatch in late spring and feed on leaves, creating webs for protection. They develop into moths in the summer, often appearing in June/July, and then lay eggs on the trees in late autumn. The eggs hatch over winter, leading to an "explosion of feeding activity" in the spring.
Mild winters are sometimes blamed for increased ermine moth populations, as they allow the caterpillars to survive and reproduce in larger numbers.
Willow Ermine moth
I will observe this remarkable phenomenon over the next few months to see how the willow trees recover.
No comments:
Post a Comment