49.281 Gypsonoma sociana (Mottled White Tortrix)
ws: 12-15mm; Jun-Aug; black poplar, aspen (Populus nigra/tremula), sallow (Salix spp); common throughout GB
Synonym: Gypsonoma neglectana (Pierce & Metcalfe)
Synonym: Gypsonoma neglectana (Pierce & Metcalfe)
ID: Distinguished from other Gypsonoma species by the clear white frons, creamy white in G.dealbana.
Male genitalia: ventral border of valva shallowly emariginate towards apex; deeply emarginate in G.dealbana
Female genitalia: Illustrated and described by Pierce and Metcalf, illustrated but not described in MBGBI5.2, shown at Moth Dissection.
Distinguishing features can be summarised thus: G.sociana: posterolateral angles of ostial plate ~90°; colliculum ~2x as long as wide, occupying ~⅓ the length of the ductus bursae and not continuous with the ostial plate. G.dealbana: ostial plate not so angular; colliculum ~4x as long as wide and occupying ~½ the length of the ductus bursae.
The illustrations in MBGBI5.2 do not show any very convincing difference between G.sociana and G.dealbana.
The crucial difference described and illustrated by P&M is that the ostial plate is angular in G.sociana and rounded in G.dealbana; they also illustrate the ostial plate as occupying ~80% of the diameter of S8 in G.sociana so that the plate is 2-3x wider than it is long, ~50% in G.dealbana and <2x wider than long. A difference in the ostial plate is also seen when comparing images at Moth Dissection: the ostial plate of G.sociana has a transverse posterior margin with angular posterolateral corners, while in G.dealbana the posterior margin slopes anteriorly from a midline prominence. (However, it should be noted that the ostial plate in G.dealbana is more naturally placed in the dorso-ventral plane of the abdomen so that the dorsal edge becomes the posterior margin in a set specimen, and the degree to which this transition can be achieved will vary with the degree of compression). The colliculum is not mentioned by P&M but in the images at Moth Dissection the differences are clear.
Male genitalia: ventral border of valva shallowly emariginate towards apex; deeply emarginate in G.dealbana
Female genitalia: Illustrated and described by Pierce and Metcalf, illustrated but not described in MBGBI5.2, shown at Moth Dissection.
Distinguishing features can be summarised thus: G.sociana: posterolateral angles of ostial plate ~90°; colliculum ~2x as long as wide, occupying ~⅓ the length of the ductus bursae and not continuous with the ostial plate. G.dealbana: ostial plate not so angular; colliculum ~4x as long as wide and occupying ~½ the length of the ductus bursae.
The illustrations in MBGBI5.2 do not show any very convincing difference between G.sociana and G.dealbana.
The crucial difference described and illustrated by P&M is that the ostial plate is angular in G.sociana and rounded in G.dealbana; they also illustrate the ostial plate as occupying ~80% of the diameter of S8 in G.sociana so that the plate is 2-3x wider than it is long, ~50% in G.dealbana and <2x wider than long. A difference in the ostial plate is also seen when comparing images at Moth Dissection: the ostial plate of G.sociana has a transverse posterior margin with angular posterolateral corners, while in G.dealbana the posterior margin slopes anteriorly from a midline prominence. (However, it should be noted that the ostial plate in G.dealbana is more naturally placed in the dorso-ventral plane of the abdomen so that the dorsal edge becomes the posterior margin in a set specimen, and the degree to which this transition can be achieved will vary with the degree of compression). The colliculum is not mentioned by P&M but in the images at Moth Dissection the differences are clear.
§1 Strumpshaw Fen, Norfolk; 18/06/2012; male; fw 6.2mm
§2 Strumpshaw Fen, Norfolk; 18/06/2012; male
§3 Strumpshaw Fen, Norfolk; 10/07/2015; female; fw 6.6mm; to light
§4 Orlestone Forest, Kent; 17/06/2020; male; fw 6.1mm
§5 Kishorn, Ross & Cromarty; 22/06/2022; male; fw 5.5mm
§6 Kishorn, Ross & Cromarty; 23/06/2022
§7 Foulness, Essex; 24/06/2017; female; fw 6.9mm
All images © Chris Lewis
§2 Strumpshaw Fen, Norfolk; 18/06/2012; male
§3 Strumpshaw Fen, Norfolk; 10/07/2015; female; fw 6.6mm; to light
§4 Orlestone Forest, Kent; 17/06/2020; male; fw 6.1mm
§5 Kishorn, Ross & Cromarty; 22/06/2022; male; fw 5.5mm
§6 Kishorn, Ross & Cromarty; 23/06/2022
§7 Foulness, Essex; 24/06/2017; female; fw 6.9mm
All images © Chris Lewis
Page published 14/01/2013 (§1-2) | §3 added 17/12/2015 | §4 added 24/01/2021 | §5&6 added 11/12/2022 | §7 added and female genitalia text amended 09/07/2024