A rare micromoth species has been discovered in East Cork.

In a significant milestone for Irish biodiversity, the elm leaf-mining micromoth, Stigmella viscerella, has been documented in Ireland for the first time.

This important discovery was made in October near Carrigtwohill by John Emmet O’Sullivan, Project Manager of Cork Nature Network’s Valuing Insects initiative, when six distinctive, coiled mines created by this micromoth caterpillar were identified on the leaves of wych elm in a hedgerow outside Carrigtwohill.

The find represents a remarkable extension of this species’ previously known range in Europe, as it had only been recorded as far west as Liverpool in England until now.

“Stigmella viscerella larvae mine elm leaves, meaning they feed in between the top and bottom layers of a leaf,” said John.

“In doing this they create distinctive mines that are shaped like intestines which is where they get their species name viscerella from, referring to viscera. Finding Stigmella viscerella in Ireland is something of a milestone for the Valuing Insects initiative in understanding insect diversity in the country.

“This tiny moth’s presence here shows how our native insect biodiversity continues to surprise us and is ever-changing. It also highlights the persistence of species of elm in Ireland, even in the face of significant challenges like Dutch elm disease.”

“This disease significantly impacted elm populations, which may have limited the diversity of elm-associated insect species in Ireland until now. The distinctive mines on wych elm leaves are a testament to the incredible complexity of our ecosystems and the importance of conserving them for future generations.”

John’s findings, soon to be published in the Irish Naturalists’ Journal, build on decades of research into elm-associated biodiversity across Europe, offering fresh insights into Ireland’s insect fauna.