35.116 Scrobipalpa obsoletella (Fischer von Röslerstamm, 1841)

Status and Distribution

Widely scattered but local over much of England with a strong preference for coastal eastern and southern regions but has been found regularly inland; locally common on Scilly Isles; rare in Scotland, Wales and Ireland and apparently absent from the Channel Islands.

National Status: 

Nationally Scarce B

Bradley & Fletcher no: 

816
Photo courtesy of UK Moths.

Provisional Map

Maps updated with all data received by February 2016.

    Imago

    Scrobipalpa obsoletella Iken Cliff, Suffolk, 2014 (Photo: Paul Kitchener)

    Set Specimens

    Scrobipalpa obsoletella 24.viii.1989, St Mary's, Isles of Scilly (Photo: R J Heckford)

    Dissection Group

    Foodplant and Larval Feeding Signs

    Atriplex spp. (orache) including Atriplex prostrata (spear-leaved orache), see distribution map, Atriplex glabriuscula (babbington's orache) and supposedly Chenopodium spp. (goosefoot).

    In Europe on Atriplex littoralis (grass-leaved orache), A. halimus (sea orache), A. tatarica and also on Chenopodium spp. (goosefoot), both on ruderal and halophytic (salt-loving) species.

    Dry whitish frass extruding from a small hole in the stem will indicate a larva within the stem and has been found feeding within or between spun fruits of babbington's orache.

    Foodplant Map

    Habitat

    Scrobipalpa obsoletella habitat 2014 (Photo: S Palmer)  Scrobipalpa obsoletella habitat Lancashire 2017 (Photo: J Patton)  Scrobipalpa obsoletella habitat Lancashire 2017 (Photo: J Patton)

    Saltmarshes, sea banks and other coastal locations where the foodplants occur. Information relating to inland sites where larvae have been found do not appear to have been documented.

    Finding the Moth

    Larva: feeds within the stem, leaving a small hole with dry whitish frass. On babbington's orache it has been found feeding in a single fruit or, more usually, two spun together.

    Adult: flies at night and comes to light often some miles from its nearest foodplant site.

    Similar Species

    Usually the palest of the saltmarsh species and greyer than most, often lacking any sign of red-brown colouration on the wings. Similar species such as S. nitentella and S. atriplicella usually have darker forewings.

    S. nitentella was only distinguished from S. obsoletella in Britain in 1935 and as a consequence there is some uncertainty as to the true identity of some of the older records.

    Because of the sometimes considerable variation within most saltmarsh inhabiting Scrobipalpa species, identification by wing markings alone will often not be possible. Caution and care are the watchwords for this group.

    If a moth has been bred from a known foodplant, and therefore also time of year when the larva feeds and the nature of its feeding methods have been observed, this information, plus a freshly emerged moth, will allow the number of possibilites to be reduced considerably. If the bred or caught moth is a very fresh specimen and displays the distinctive markings of some species (see below) then an identification without more detailed examination should be possible in many cases.

    Those more readily identifiable when freshly emerged by the forewing markings are listed below. However all of these also have variation in their wing markings which, when the obvious features are obscured or worn, will then resemble some other Scrobipalpa species.

    Scrobipalpa suaedella - those with an obvious clear pale ochreous dorsal quarter to the forewing.

    Scrobipalpa obsoletella - those with the forewing a pale greyish colour lacking any red-brown colouration and appearing paler in the final one-third due to a pale postmedial fascia.

    Scrobipalpa ocellatella - those with the prominent angled fascia at three quarters on the forewing and dark markings contrasting with the surrounding paler ground colour.

    In cases where there is any doubt, particularly where worn light-trapped specimens are concerned, dissection will be essential to obtain an accurate identification until a good familiarity is built up with the range of species and their markings at a particular site.

    Even genitalia differences are often small but are constant between the various species. It is advisable to seek confirmation of identifications by genitalia until familiarity is built up with this genus.

    Larval Occurrence

    Larval Occurrence

    Flight Period

    Flight Period

    Two or more generations from May to early September.

    Earliest: 7th May 2011 (VC19 and VC61)

    Latest: 2nd September 1997 (VC34)