23 Aug 2019

Pollinator of the day #7 – Cinnabar (Tyria jacobaeae)

Ardd Fotaneg · Botanic Garden

The cinnabar is a widespread species of day-flying moth. It is readily disturbed by day although it also flies at night. The species is named after the bright red, mercury sulphide minerals cinnabar and cinnabarite. The caterpillars are also distinctive and easily identified by their alternating orange and black stripes; these colours are a form of aposematism, a pattern or set of colours which serve as a warning to predators. This is because cinnabar caterpillars obtain toxic chemicals from their food plants, ragwort and groundsel (Senecio spp.), which makes them taste very unpleasant.

Despite being considered a common UK species, Butterfly Conservation’s 2006 report on the state of Britain’s larger moths showed that the cinnabar had declined by 83%, classing it as ‘Vulnerable’.  While this dramatic change is likely due to many reasons, there is little doubt that misconception surrounding the toxicity of ragwort to livestock is a contributing factor to its decline. Farmers and landowners have been encouraged to eradicate the plant to minimise the risks of poisoning. However, ragwort poses little threat to livestock or humans unless considerable amounts are consumed daily, and the only real risk is posed when dried in hay, where it loses its acrid taste. As cinnabar caterpillars feed exclusively on ragwort and groundsel their slow eradication from our countryside poses a major threat to the survival of this species.

To learn more about our pollinators, come and take part in our Pollinator Festival, August 24-26 2019.