Davey, P., 2009: A strongly migratory species with a global distribution (apart from Australasia) occurring annually across southern districts of England, the larval foodplant is unknown. Like the Vestal, this species does not seem to be able to survive the UK winter in any stage. The markings and light brown colouration of the adult male are in stark contrast to the much darker, purple-hued, female. In Dorset, the moth has been recorded in sixteen of the past twenty years. In favourable seasons, immigrants spawn up to two resident broods, and these are undoubtedly supplemented by further influxes from abroad whenever suitable weather conditions arise. Brood peaks double or treble in size with time. The moth has been recorded in twenty-four of the past twenty-seven years.

Two moths were trapped at light within an alder swamp at St Leonard's Peats on 6 July 1998 (P Davey), in a year when relatively large numbers of Gems were recorded. The locality contains much common marsh-bedstraw (Galium palustre) and fen bedstraw (Galium uliginosum), host plants for many 'Carpets'. There was no opportunity for immigration at the time of capture.

Recorded in 32 (80%) of 40 10k Squares.
First Recorded in 1934.
Last Recorded in 2019.
(Data up to end 2019)