Insecta : Lepidoptera : NoctuidaeButterflies and Moths

Stilbia anomala (Haworth, 1812)

Anomalous

Stilbia anomala

Description: Wingspan 29-36 mm. Forewings narrow at the basal area and widening at the termen. The colour is generally mauve grey, but it can show variation between individuals. Stigmata similar to base colour but outlined in black. Antemedian and post median lines indistinct. There is a v-shaped mark between the stigmata and the dorsum which is clearly visible. Hindwings pale white with fine dark veining. Early August to mid-September.

World Distribution: An Atlantic-Mediterranean species which is widespread in western Europe in uplands and sandy heaths from Portugal and northern Spain to the Vosges Mountains in France.

Irish Distribution: Widely distributed and recorded mainly from regularly trapped coastal localities such as Murlough National Nature Reserve, Ballykinler, Down, the Umbra, Londonderry and Rathlin Island, Antrim. It also occurs inland at several sites in the west Fermanagh hills at Legalough, Belcoo, Monawilkin and Gortmaconnell Rock. In Down it has also been taken at Seaforde and from a suburban garden in the Greater Belfast area.

Ecology: A small species found on coastal heaths and moorland. Adults (especially males) become active at dusk and are attracted to light in small numbers. Individuals often rest on Heather Calluna vulgaris and other low vegetation after dark. The larvae feed from October to March on various grasses. It overwinters as a larva.

Key Identification Features:

  • Narrow wings held tightly over the body
  • V-shaped mark between stigmata
  • Pale hindwings with darker veining

Distribution Map from NBN: Stilbia anomala at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Stilbia anomala at iNaturalist World Species Observations database.

 Thompson, R. & Nelson, B. (2023). Stilbia anomala. (Haworth, 1812). [In] Moths of Northern Ireland.
https://habitas.org/moths/species.php?item=6500. Accessed on 2026-11-02.