35.039 Bryotropha politella (Satin Moss-moth)
ws: 12-16mm; May-Jul; common on moorland in Scotland, Wales and N.England, local and uncommon in S.England
Bryotropha politella §1 male
ID: External Features: Labial palp S2 with conspicuous furrowed brush; ws 14-16mm > B.politella/desertella/terrella
Smaller specimens of this species cannot be narrowed down to these three - and are not keyed in MBGBI4.2
Forewing with a shiny texture, hence the specific and English names
Sexually dimorphic as follows: antenna - ♂ dark fuscous ♀ochreous, ringed fuscous; forewing - ♂brown-grey, ♀ochreous to ochreous-grey; apical area of forewing - ♂ concolorous, ♀darker due to irroration with brownish scales; hindwing cilia - ♂ uniform, ♀ often with a darker ciliary line.
B.politella/desertella are distinguished in the key in MBGBI4.2 on shape of the forewing apex - somewhat pointed in B.politella, more rounded in B.desertella; and in the female on forewing ciliary lines as follows: B.politella one ciliary line, B.desertella two or more ciliary lines.
Male genitalia: Aedeagus with a whip-like apex; sacculus absent > B.politella. The broad gnathos with an apical sclerotised 'nail' is also highly characteristic.
Female genitalia: Posterior margin of S8 deeply excavate ventrally to more than half its length (the sides of the excavation converging posteriorly); signum a pleated sheet with 2 transverse ridges; signum shorter than apophyses anteriores.
Smaller specimens of this species cannot be narrowed down to these three - and are not keyed in MBGBI4.2
Forewing with a shiny texture, hence the specific and English names
Sexually dimorphic as follows: antenna - ♂ dark fuscous ♀ochreous, ringed fuscous; forewing - ♂brown-grey, ♀ochreous to ochreous-grey; apical area of forewing - ♂ concolorous, ♀darker due to irroration with brownish scales; hindwing cilia - ♂ uniform, ♀ often with a darker ciliary line.
B.politella/desertella are distinguished in the key in MBGBI4.2 on shape of the forewing apex - somewhat pointed in B.politella, more rounded in B.desertella; and in the female on forewing ciliary lines as follows: B.politella one ciliary line, B.desertella two or more ciliary lines.
Male genitalia: Aedeagus with a whip-like apex; sacculus absent > B.politella. The broad gnathos with an apical sclerotised 'nail' is also highly characteristic.
Female genitalia: Posterior margin of S8 deeply excavate ventrally to more than half its length (the sides of the excavation converging posteriorly); signum a pleated sheet with 2 transverse ridges; signum shorter than apophyses anteriores.
Dissection
Male genitalia
Female genitalia
§1 Cyffdy Farm, Gwynedd; 24/06/2010; male; fw: 7.5mm
§2 Nethybridge, Inverness-shire; 11/07/2011; male; fw: 7.5mm
§3 Torver, Cumbria; 15/07/2015; male; fw 7.5mm; to light
§4 Bampton Grange, Cumbria; 12/06/2017; male; fw 7.2mm
§5 Bampton Grange, Cumbria; 13/06/2017; female; fw 6.4mm
§6 Bampton Grange, Cumbria; 18/06/2017; female; fw 6.1mm
All images © Chris Lewis
§2 Nethybridge, Inverness-shire; 11/07/2011; male; fw: 7.5mm
§3 Torver, Cumbria; 15/07/2015; male; fw 7.5mm; to light
§4 Bampton Grange, Cumbria; 12/06/2017; male; fw 7.2mm
§5 Bampton Grange, Cumbria; 13/06/2017; female; fw 6.4mm
§6 Bampton Grange, Cumbria; 18/06/2017; female; fw 6.1mm
All images © Chris Lewis
Page published 01/11/2011 | Specimen §2 added 18/12/2011 | §3 added 13/12/2015 | §4-6 added 18/03/2018
