49.260 Zeiraphera isertana (Cock's-head Bell)
ws: 14-19mm; Jul-Aug; oak (Quercus spp); common in oak woodlands throughout GB.
Synonym: Zeiraphera corticana (Pierce & Metcalfe)
Synonym: Zeiraphera corticana (Pierce & Metcalfe)
Zeiraphera isertana §9
ID: Very variable in colour and expression of markings. Similar to but averages smaller than Z.griseana (ws16-22mm). Distinguished by the comparatively small and usually trapezoidal blotch of ground colour on the dorsum of the forewing which in Z.griseana is large, usually triangular or subquadrate and almost invariably reaches the costa.
Male genitalia: Zeiraphera species have a "shouldered" tegumen with a small uncus, prominent drooping socii, the costa (dorsal margin) of the valva shows a small prominence medially and the ventral border shows an indentation at the junction of sacculus and valvula. Z.isertana has a narrow valva only slightly broader at the base than at the apex, its ventral border is shallowly concave subapically; and the medial costal prominence is more well-marked than in the other species. Z.griseana has a more angular sacculus and a deeper indentation at the junction of the sacculus with the valvula than in the other species; the ventral border of the valvula is smoothly convex and the valvula is much broader at its base than at its apex. Z.ratzburgiana has a very shallow indentation at the junction of sacculus and valvula, the ventral margin of the valvula is very convex at ~junction of proximal 1/3 with distal 2/3, the valvula is broad and narrows relatively little in apical third, and the medial costal prominence is minimal. Z.rufimitrana is not shown at dissection group; the drawings in Pierce and Metclafe suggest a relatively short broad valva. P&M also describes differences in the number of cornuti: ~50 for Z.griseana, ~13 for Z.ratzeburgiana, ~21 for Z.rufimitrana and ~15 for Z.isertana.
Summary:
Z.isertana - valva narrow, medial costal prominence strong
Z.griseana - valva broad, tapering; sacculus angular
Z.ratzburgiana - valva broad, covexity of valva more prominent than concavity of sacculus/valvula junction
Z.rufimitrana - valva broad, short
Female genitalia: the number and size of the signa and the shape of a plate connecting the apophyses anteriores seems to provide a distinction between the Zeiraphera species. All except Z.rufimitrana are shown at Moth Dissection. All 4 species are illustrated in Pierce & Metcalfe who also provide a limited description. Z.griseana has a single signum, Z.rufimitrana has one standard horn-like signum and one small scobinate plate, both Z.ratzeburgiana and Z.isertana have 2 horn-like signa. P&M describe the plate connecting the apophyses anteriores as "long emarginate" in Z.ratzeburgiana and Z.griseana, "long deeply emarginate" in Z.rufimitrana and "slightly emarginate" in Z.isertana. Specimens §1,3&5 clearly have 2 standard horn-like signa and the plate connecting the apophysis anteriores is clearly short (in the antero-posterior direction).
Male genitalia: Zeiraphera species have a "shouldered" tegumen with a small uncus, prominent drooping socii, the costa (dorsal margin) of the valva shows a small prominence medially and the ventral border shows an indentation at the junction of sacculus and valvula. Z.isertana has a narrow valva only slightly broader at the base than at the apex, its ventral border is shallowly concave subapically; and the medial costal prominence is more well-marked than in the other species. Z.griseana has a more angular sacculus and a deeper indentation at the junction of the sacculus with the valvula than in the other species; the ventral border of the valvula is smoothly convex and the valvula is much broader at its base than at its apex. Z.ratzburgiana has a very shallow indentation at the junction of sacculus and valvula, the ventral margin of the valvula is very convex at ~junction of proximal 1/3 with distal 2/3, the valvula is broad and narrows relatively little in apical third, and the medial costal prominence is minimal. Z.rufimitrana is not shown at dissection group; the drawings in Pierce and Metclafe suggest a relatively short broad valva. P&M also describes differences in the number of cornuti: ~50 for Z.griseana, ~13 for Z.ratzeburgiana, ~21 for Z.rufimitrana and ~15 for Z.isertana.
Summary:
Z.isertana - valva narrow, medial costal prominence strong
Z.griseana - valva broad, tapering; sacculus angular
Z.ratzburgiana - valva broad, covexity of valva more prominent than concavity of sacculus/valvula junction
Z.rufimitrana - valva broad, short
Female genitalia: the number and size of the signa and the shape of a plate connecting the apophyses anteriores seems to provide a distinction between the Zeiraphera species. All except Z.rufimitrana are shown at Moth Dissection. All 4 species are illustrated in Pierce & Metcalfe who also provide a limited description. Z.griseana has a single signum, Z.rufimitrana has one standard horn-like signum and one small scobinate plate, both Z.ratzeburgiana and Z.isertana have 2 horn-like signa. P&M describe the plate connecting the apophyses anteriores as "long emarginate" in Z.ratzeburgiana and Z.griseana, "long deeply emarginate" in Z.rufimitrana and "slightly emarginate" in Z.isertana. Specimens §1,3&5 clearly have 2 standard horn-like signa and the plate connecting the apophysis anteriores is clearly short (in the antero-posterior direction).
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§1 Strumpshaw Fen, Norfolk; 21/08/2012; female
§2 Bookham Common, Surrey; 16/07/92013; male; fw 7.3mm §3 Bookham Common, Surrey; 16/07/92013; female; fw 8.7mm §4 Bookham Common, Surrey; 16/07/92013; male; fw 7.0mm §5 Belfairs Woods, Essex; 18/07/2014; female; fw 8.0mm §6 Westcliff-on-sea, Essex; 01/07/2015; male; fw 7.6mm; to light §7 Seathwaite, Cumbria; 23/07/2016; male; fw 6.5mm; to light §8 Orlestone Forest, Kent; 11/07/2018; female; fw 7.4mm §9 Orlestone Forest, Kent; 07/07/2019 All images © Chris Lewis |
§10 Pound Wood, Essex; 30/06/2019
§11 Orlestone Forest, Kent; 24/06/2020; female; fw 8.1mm §12 Pound Wood, Essex; 26/06/2020 §13 Stour Wood, Essex; 14/07/2021; male; fw 6.7mm; to light |
Page published 12/01/2013 (§1) | §2 added and text amended 20/07/2013 | §3 added 21/07/2013 | §4 added 01/12/2013 |
§5 added 19/01/2015 | §6 added 14/11/2015 | §7 added 05/07/2017 | §8 added 21/05/2019 | §9 added 31/01/2020 | §10 added 22/02/2020 |
§11&12 added 27/01/2021 | §13 added 13/08/2021
§5 added 19/01/2015 | §6 added 14/11/2015 | §7 added 05/07/2017 | §8 added 21/05/2019 | §9 added 31/01/2020 | §10 added 22/02/2020 |
§11&12 added 27/01/2021 | §13 added 13/08/2021
