In the summer of 2025, I first encountered a tree infested with the intricate webbings spun by Ermine moth caterpillars in Amsterdam’s Vondelpark. It’s an eerie sight: the tree stripped entirely of foliage and shrouded in silver-white silk, with hundreds of caterpillars crawling across the delicate architecture. As a biodesigner, though, it’s a thrilling display of collective behavior crafting biological structures. While the tree stands leafless for a time, this temporary infestation leaves no lasting harm to healthy specimens. The silk naturally disintegrates within months, recycling nutrients back to the soil.