The Cinnabar Moth (Tyria jacobaeae) is a brightly coloured moth that flies during the day. As a result of this it is often mistaken for a butterfly. It gets its name from the red mineral cinnabar.

The Cinnabar Moth can use many members of the genus Senecio as foodplants but for long term success larger plants that persist for a long time are necessary. Some uninformed people who campaign against ragwort say that groundsel is sufficient as a foodplant. This is not true. While the caterpillars can and do use groundsel the plants are small and unlikely to support large batches of eggs also groundsel is a more ephemeral plant that does not normally persist on sites.

Also there is the factor of groundsel being less help for metapopulation persistence. The caterpillars of the Cinnabar Moth are very distinctive. They are striped black and orange-yellow, rather as though they are wearing a football jersey. They absorb the bitter tasting alkaloids that make ragwort distasteful to animals and become distasteful to birds as a result. The bright colours are a warning to birds not to eat them.

The Cinnabar Moth is still relatively common. In Britain according to the State of Britain's moths report compiled by Butterfly Conservation and Rothamstead Research in 2003 which covered the state of moths between 1968 and 2002 between a third and a half of the survey moth traps catch this species and there was no significant change in that over the period.

The size of the catches however is a cause for concern. These decreased over the period by eighty three percent.

There is a common myth in circulation that there has been a plague of ragwort as a result of the decline in the cinnabar moth. In fact the latest research shows that if anything ragwort has been declining.