Thurles Information

Spotted here in Thurles on Monday last, the first Cinnabar moth (Tyria jacobaeae) of the season. Native to Ireland and indeed Europe, Cinnabar moths are daytime-flying moths, with distinctive pinkish-red and black wings.

Cinnabar moths measure about 20mm (0.79in) in length with a wingspan of some 32–42mm (1.3–1.7in) and acquires its named from the red mineral Cinnabar, because of the red patches on its predominantly black wings.

Interesting to note that this moth has been introduced into New Zealand, Australia and North America to control Ragwort (latter poisonous to horses and other livestock), on which its larvae feed.
This Ragwort diet, eaten by their pale yellow and black striped larvae, leaves them unpalatable to their would-be predators. Females can lay up to 300 eggs, in batches of 30 to 60 on the underside of Ragwort leaves and their caterpillars being voracious eaters; a large population can strip entire patches of ragwort clean, within a very short period of time.

Though not considered very rare in Ireland, the Cinnabar moth remains, annually, in grave danger due to the Noxious Weeds Act of 1936, which makes it an offence for the owner or occupier of lands not to prevent the growth and spread of Ragwort. In 2020, some 52 “notices to destroy” were issued to land owners, by the Department of Agriculture, for the presence of Ragwort being on their property and in 2021, some 22 such notices were also issued.
Many caterpillars will starve if their food runs out before they are fully grown, so as competition intensifies the caterpillars become more aggressive and may even turn to cannibalism in their quest for calories.