Identification

Great care is needed in separating the Thera species, especially Spruce Carpet from Grey Pine Carpet. Apparently there are no consistent differences in the genitalia of these two species, but the males can be separated by viewing the antennae through a hand lens in good light. Spruce Carpet’s having a pronounced ‘shoulder’ at the distal end.

Recording method

Comes to light.

Life cycle

Two overlapping generations. Overwinters as a small larva from the autumn to May, and again, June and July, with pupation taking place close to the ground.

Larval foodplants

Larvae feed on many other conifers than spruces, including pines, firs, cedars and occasionally cypresses.

Habitat

Coniferous plantations, but also most other habitats where the conifer foodplants are found.

History

First recorded for Dumfries and Galloway for VC72 in 1862 near Dumfries by Lennon who thought it was ‘not common’, first for VC73 was in 1874 from the Castle Douglas by Robinson-Douglas and for VC74 in 1897 at Corsemalzie by Gordon who found it ‘common in fir woods’.

However, the Spruce Carpet moth Thera britannica was only first described as a species in 1926 with moths before that date referred to as Thera variata (and other synonyms), a name that is now reserved for a very similar European species not found in the UK.  The Grey Pine Carpet Thera obeliscata is also very closely related and because of the difficulties in correctly identifying these very similar moths all of the early records must be questionable.  This moth has been recorded since 1970 for VC73 in 1970 near Glen Trool village by Geoff Shaw, for VC74 in 1976 at Penninghame House, north of Newton Stewart in the Rothamsted moth trap there and for VC72 in 1993 at Kirkton by Richard Mearns.