Biology
Biological features are of little help in identification.
Flight season: all fly in April; E.unimaculella, semipurpurella and sangi start in March; D.subpurpurella and E.sparrmannella continue into May.
Distribution: all except P.chrysolepidella are widespread in GB; P.chrysolepidella is more restricted to the south
Habitat: all are woodland species
Foodplant: D.semipurpurella - oak; P.chrysolepidella - hazel, hornbeam; Eriocrania species - all birch
Size: Ranges overlap considerably such that size is of no help in identification
Biological features are of little help in identification.
Flight season: all fly in April; E.unimaculella, semipurpurella and sangi start in March; D.subpurpurella and E.sparrmannella continue into May.
Distribution: all except P.chrysolepidella are widespread in GB; P.chrysolepidella is more restricted to the south
Habitat: all are woodland species
Foodplant: D.semipurpurella - oak; P.chrysolepidella - hazel, hornbeam; Eriocrania species - all birch
Size: Ranges overlap considerably such that size is of no help in identification
External features
Dyseriocrania subpurpurella has a golden forewing ground colour and is the only species that can be identified without dissection.
The other 7 species have a purple forewing ground colour.
E.sangii/semipurpurella can be distinguished from the remaining 5 species by: "hindwing with very narrow hair-like scales in discal area" compared with "broader scales in the discal area". The images below illustrate the difference in hindwing scale breadth for E.sangii (narrow) and E.unimaculella (broad).
Other than D.subpurpurella, all other Eriocraniidae require genital dissection for specific identification.
Dyseriocrania subpurpurella has a golden forewing ground colour and is the only species that can be identified without dissection.
The other 7 species have a purple forewing ground colour.
E.sangii/semipurpurella can be distinguished from the remaining 5 species by: "hindwing with very narrow hair-like scales in discal area" compared with "broader scales in the discal area". The images below illustrate the difference in hindwing scale breadth for E.sangii (narrow) and E.unimaculella (broad).
Other than D.subpurpurella, all other Eriocraniidae require genital dissection for specific identification.
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MBGBI1 gives the impression that the species can be identified on external features, as presented in the table below. In reality, other than the features listed above, the distinctions listed in this table are almost entirely unreliable. All the "purple" species require genital dissection
External features |
Ref: MBGBI1 |
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Forewing ground colour |
Hindwing scales |
Other features |
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Golden +/- purple spots |
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Purple or Gold with much purple |
Narrow |
Conspicuous tornal spot (usually) |
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" |
" |
Markings weak (usually) |
|
Purple |
Broad |
Conspicuous silvery tornal spot, forewing elongate |
|
" |
" |
Without conspicuous tornal spot, forewing elongate |
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Golden, strigulate and suffused purple |
" |
Head with pale yellow hairs, forewing broad |
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" |
" |
Head with mixed fuscous and whitish hairs, forewing broad |
Eriocrania sparmannella |
Page written 07/05/2021
