The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Confined in the British Isles to Cornwall. Its distribution on the Continent is rather strange, being widespread across the central latitudes, but absent from the extreme south and north.
Very local even within its restricted distribution. It is most widespread on the Lizard Peninsula - found widely on the more exposed rocky seacliffs between Loe Pool and Beagles Point, wherever herb-rich grassland and grass heath is developed and where rocky outcrops are covered in mats of thyme. It also occurs along the south-west coasts of West Penwith and at Nare Head. A report from Chapel Porth needs further investigation.
Habitat & Ecology
It occurs on its foodplant Wild Thyme Thymus polytrichus where it grows in large mats in hot dry situations such as over bare-rock on south-facing cliffs, or in the therophyte zone of the extreme cliff edge. Adults and larvae occur on flowerheads and leaves of the host, and may also be found on the ground beneath the plants. Population densities are rarely high.
Abandonment of coastal grazing is the main threat, leading to the development of denser and coarser vegetation except where exposure is limiting. The erosion of vegetation by visitor trampling or heavy grazing can be also be damaging.
The restoration or maintenance of cliff grazing is beneficial. The majority of sites are owned by The National Trust and fall within SSSI.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.