These beautiful specimen’s are Mullein moth caterpillars. The moth’s lay eggs primarily on Verbascum, Buddleja and Scrophularia species towards the end of spring. Hatching within 10 days, the caterpillars feed vigorously on the host, Verbascum nigrum, leaving infested plants stripped of their foliage.

There are four instar stages of a mullein caterpillar, the first stage is very slim and dark, with each moult they become brighter in their colouration. Most caterpillars reach their final instar by the end of July and will then leave the food plant to pupate in the soil. The pupa is formed inside a silk cocoon encased by particles of soil and small stones that remains under the soil surface for up to 5 years before emerging as a moth.