Ragwort

Ragwort

Cinnabar moth caterpillars

The larvae of cinnabar moth (Tyria jacobaeae) eat the leaves and flower heads of common ragwort and can often be found during the summer months on the plant. 

They are not affected by the toxins in the plant and utilise them as a defence against predators by storing them within the caterpillar and passing them onto the adult moths, making them less palatable.

Teams of Forestry Commission workers responsible for pulling ragwort on Crown Land in the New Forest are instructed to leave the weed intact if they come across plants with caterpillars feeding on them. If there is a need to pull plants that host cinnabar larvae, the caterpillars are shaken off to allow them to crawl to the younger ragwort plants that are not pulled up. Cinnabar moth larvae also feed on groundsel.

Whilst cinnabar moths are widespread, at least 30 other insect species (and 14 fungi) are entirely reliant on ragwort, and about a third of the insects are scarce or rare.

Ragwort is also a critically important nectar source for hundreds of species of butterflies, bees, moths, flies and other invertebrates, helping to maintain what remains of their much declined populations in the UK countryside.

  1. Ragwort
  2. Cinnabar moth caterpillars (you are here)

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