Seq # 185120110

Caloptilia robustella Jäckh, 1972 Species

Last modified: July 3, 2021, 9:07 a.m.

A not so common species in Belgium. During the last two decades, the species is spreading. Probably underrecorded, because of the similarity to the related Caloptilia alchimiella.


Family: Gracillariidae > Subfamily: Gracillariinae > Tribus: Gracillariini > Genus: Caloptilia > Species: Caloptilia robustella
Vernacular names
Eikensteltmot (NL), New oak slender (EN)
First mention in Belgium
Coenen F. 1981a. Troisième contribution à la connaissance des Microlépidoptères de Belgique. Caloptilia robustella Jäckh, espèce nouvelle pour la faune belge (Lep. Gracillariidae). — Linneana belgica 8: 261–266. On page 261.




Forewings reddish brown with a conspicuous yellow triangular spot at the middle of the costa. This spot is not prolonged towards the apex. Similar to Caloptilia alchimiella but in this species the triangular spot is prolonged towards the apex. For other differences with Caloptilia alchimiella see under that species.

Museum specimens

Specimens in nature


Very similar to the mine of Caloptilia alchimiella.
See also and

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The last instar constructs an oval, silken cocoon on the underside of a leaf. This cocoon is usually more yellowish than the one of Caloptilia alchimiella.

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The first instars live in a short gallery at the underside of a leaf, becoming a blotch and later in 2 or 3 successive cones, rolled down at the top of a lobe. In contrast with Caloptilia alchimiella, this species has also a generation of larvae during May–June.
Hibernating in the pupal stage. The adults come to light.

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Flight periods

The adults fly in several ill defined generations a year: from April till November.

Observed on

Host plant (species):
Quercus robur
Host plant (genera):

The larvae feed on Quercus, rarely on Fagus.

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This species seems to prefer somewhat more xerothermic localities than the related Caloptilia alchimiella.

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