Cinnabar Moth
Fast Facts
Latin name: Tyria jacobaeae
Notable feature: Orange and black-striped caterpillars
Conservation Status: Not Evaluated
Where in the UK: Widely distributed across the UK, except in northern Scotland.
Cinnabar Moth (Tyria jacobaeae) © Dan TP
The Cinnabar Moth (Tyria jacobaeae) is a macro moth found throughout most of the UK. Its distinctive colouring makes it one of the most identifiable moths – forewings are black with a red line and two red spots at the base of each wing, the hindwings are red. The caterpillars are orange and black striped.
This species is typically found in well drained, short sward grassland, including sand dunes and heathland and lots of other open habitats such as gardens and woodland rides.
- Size: Body length 20mm, wingspan between 32-42mm.
- Life span: Annual
- Diet: The caterpillars feed on the leaves and flowers of Common Ragwort (Senecio jacobaea). It can also be occasionally found on other ragworts and groundsels.
- Reproduction: Females can lay up to 300 eggs, usually in batches of 30 or 60 on the underside of Ragwort leaves. When the caterpillars (larvae) hatch they feed around the area of the hatched eggs but as they get bigger and moult (instars), they mainly feed on the leaves and flowers of the plant and can be seen out in the open during the day from late June to early September. The caterpillar is distinctively striped black and orange, and as they are found exclusively on Ragwort can be easy to identify. The toxins from the Ragwort leaves is stored in the caterpillar’s body (and even remains when they are an adult moth). The caterpillars overwinter as pupa in a cocoon under the ground. The adult moths emerge around mid-May and are on the wing up until early August, during which time males and females will mate and eggs are laid.
- When to see: Despite being predominantly nocturnal, adult Cinnabar Moths can be seen flying during the day between mid-May and early August. Caterpillars can be seen from July to early September.
- Population Trend: Declining
- Threats: The persecution of their food plant, Common Ragwort, has led to declines of the Cinnabar Moth across the UK. Ragwort contains toxins (pyrrolizidine alkaloids) which can cause liver poisoning if enough of the plant is digested. Grazing animals and ragwort have co-existed for thousands of years, yet the plant has seen persecution due to the perceived risk to livestock. There are actually very few proven cases of ragwort poisoning in pasture however, the real risk is if ragwort is present in dried hay which is then fed to livestock. Due to this negative focus on the plant, the importance of Ragwort and the species it supports, like the Cinnabar Moth, are often overlooked. As well as the Cinnabar Moth, ragwort is an incredibly important source of nectar and pollen for other insects in the summer months – including many bees and butterflies. Over 30 insects in the UK are entirely reliant on ragwort for their survival.
- Interesting Fact: The Cinnabar Moth was originally named after the bright red mineral ‘cinnabar’, which was once used by artists as a red pigment for painting.
How you can help:
Buglife is working to increase awareness of invertebrates and the Cinnabar Moth through our projects and campaigns, but we need your help!
Join a recording scheme and log your finds – download the iRecord app and get recording!
Spare a thought for this species when you come across Ragwort – and think twice before pulling up the plants. A weed is just a plant where we don’t want it!
Do remember that we rely on donations to continue our work. If you have searched, found and learned about our incredible invertebrates on our website, please do consider Making a Donation, Becoming a Member or maybe even making a purchase in our shop. For more ideas on how to support our work find out how to Get Involved. Thank you 🕷
You might also be interested in