Caloptilia betulicola (Hering, 1928)
red birch slender
Betula pubescens, Vlaardingen (herb. B van As)
mine with initial corridor; same mine, lighted from behind
The mine starts with an inconspicuous epidermal corridor, mainly visible by a reddish brown frass line. During the following larval stage a blotch is formed, that quickly develops into a tentiform mine; the epidermis is brown. Generally the mine is lower-surface, but upper-surface mines are not rare. Frass in a mass of grains in a corner of the mine. After having left its mine the larva moves twice. First it lives in a rolled (sometimes just folded) leaf margin, after that in a leaf that is transversely rolled downwards, starting from the leaf tip; generally the entire leaf is involved. Pupation in a white, strongly shining, parchment-like cocoon, that is fixed with silk to the leaf margin.
Betula pendula, pubescens.
Preference for suckers and seedlings.
Larvae in May and July, pupae in May-June and in August (Emmet, Watkinson & Wilson, 1985a).
BE recorded (Phegea, 2008).
NE recorded (Kuchlein & de Vos (1999a; Microlepidoptera.nl, 2008).
LUX not recorded (Fauna Europaea, 2008).
distribution within Europe
From Scandinavia and the north of European Russia to the Pyrenees and Alps, and from Ireland to Poland and Slovakia (Fauna Europaea, 2008); also Iberia (A & Z Laštůvka, 2014a).
Whitish with pale brown head; pronotum without black spots (contrary to Parornix betulae).
See Patočka & Zach (1995a), Patočka & Turčáni (2005a), in a shiny, yellowish cocoon.
Dorsal image of head and pronotum of the pupa of C. populetorum (at left) and C. betulicola right). The pronotum of populetorum bears a pair of elongated ridges, while that in betulicola shows a pair of shallow depressions (from Patočka & Zachs).
Also many members of the Lepidoptera family Tortricidae live in leaf rolls. However, contrary to Tortricidae larvae, Caloptilia larvae leave the outer layers of the palisade parenchyma uneaten, causing their leaf rolls to remain green (Emmet, Watkinson & Wilson,1985a).
It has long been assumed that the leaf rolls of C. betulicola would run perpendicular to the midrib, those of C. populetorum parallel with it. However, recently Ben van As has shown shoots bearing several leaf rolls where both pattern co-occurred. Apparently the rolls of both species are indistinguishable.
Bengtsson & Johansson (2011a), Biesenbaum (2010a), SCS Brown (1947a), Buszko (1992c), Deutschmann (2008a), Emmet, Watkinson & Wilson (1985a), Heckford (1986a), Hering (1927b, 1957a), Huisman, Koster, van Nieukerken & Ellis (2009a), Jaworski (2009a), Kirichenko, Triberti, Akulov ao (2019a), Klimesch & Skala (1936b), Kollár & Hrubík (2009a), Kuchlein & Donner (1993a), Kuchlein & de Vos (1999a), Laštůvka & Laštůvka (2014a), Opheim (1977a), Patočka & Turčáni (2005a), Patočka & Zach (1995a), Plóciennik, Pawlikiewicz & Jaworski (2011a), De Prins & Steeman (2013a), Robbins (1991a), Skala & Zavřel (1945a), Szőcs (1977a).