Status and Distribution
Three male specimens were found, misidentified, within British collections from Dartford Heath, Kent (1850) as Scrobipalpa artemisiella, Benfleet, Essex (1899) as S. instabilella and Erith Marshes, Kent (1926) as S. acuminatella. These were originally added to the British list as Scrobipalpa psilella in 1965 but re-identified as Scrobipalpula diffluella * in 1999 (Heckford, R. J. & Sattler, K., Ent. Gaz. vol. 50: 255-260). There have been no further records of this moth despite searches in the above areas between 1996 and 1998 and the species is considered Extinct in the British Isles.
* It is noted within Moths and Butterflies of Great Britain and Ireland Vol. 4 (2): "Until more material is obtained and the life history in Britain is discovered, their (the three specimens noted above) status remains problematic. It has been decided to assign the Britsh specimens to S. diffluella, unless further investigation shows that the British taxon is undescribed, as they best fit this species as understood by Huemer, P. & Karsholt, O., 1998, Nota lepid. 21: 37-65".
The coverage of S. diffluella in the Microlepidoptera of Europe Vol. 6 by Huemer, P. & Karsholt, O. in 2010 has not changed this situation.
It is a boreomontane species in Europe.
At present, the photograph displayed on the Natural History Museum's Cockayne website is not of this species but appears to be Anarsia spartiella. The organisers of the website have been informed of this error.
Foodplant and Larval Feeding Signs
Unknown in the British Isles, although a specimen was found amongst a series of Scrobipalpa acuminatella reared from brown blotches in an unspecified species of thistle. This requires confirmation as Scrobipalpula diffluella has not been reliably recorded on Carduus or Cirsium species elsewhere.
In Europe it feeds on Erigeron acer (blue fleabane), Homogyne alpina (purple colt's-foot), Aster alpinus* and Aster bellidiastrum* where it forms a blotch-like leaf-mine. A tenanted mine has been observed in June (location and plant species not specified).
* In the British Isles, the genus Aster has been divided with most species moved to the genus Symphyotrichum and one each to Galatella and Tripolium. It is not known if the continental aster species mentioned here have been similarly altered or not.
The locations of the three British specimens were not documented accurately enough to allow a specific habitat association to be assessed but they came from two coastal/near coastal areas and one inland site in south-east of England.
In Europe, in sharp contrast, it occurs in the boreal zone south of the Artic and in mountainous areas such as the Alps and Urals.
Finding the Moth
Adult: searches near Benfleet, Essex, and Dartford Heath and Erith Marshes, Kent, were carried out between 1996 and 1998. Any light trapping in south-east England near these localities or in similar habitats should bear this species in mind.
Larva: if, as is currently proposed, the species recorded in Britain is S. diffluella then searches for leaf mines on Erigeron acer (blue fleabane) would be worthwhile. However an open mind should be kept and investigation of any unexpected tenanted, lepidopterous, blotch leaf-mines on the large plant family Asteraceae in May or June would be worth breeding through.
It resembles a small, pale, mottled grey-brown Scrobipalpa species with a few small darker elongate spots across forewing and the head and thorax light grey (in Europe it can be quite variable in its markings). It is slightly smaller than Scrobipalpa tussilaginis which has a more uniform pale-grey appearance. Any potential specimen should be retained for further, more detailed examination and notes made as to the precise location, habitat and any plant associations observed.
The circumstances surrounding the capture of two of the three specimens were not documented but suggest a possible flight period of late June to early July. The two full dates in the British Isles were 24th June 1850 and 3rd July 1899. The third specimen was believed bred and emerged in late July 1926. No other details are known.
In Europe the species has a more varied flight perod according to the latitude and altitude at which it occurs.